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Escherichia coli cells lysogenic for temperate phage HK239 exclude phages λ, HK022, P1 vir, P2, and rII mutants of phage T4. After mutagenic treatment, four isolates were obtained for their inability to exclude T4rII. It is shown that this mutation, designated exc, is located in the prophage HK239, and that, it also abolishes the exclusion of phages λ, HK022, P1 vir, and P2.

In recent years there has been increased concern over the maintenance of open space by various levels of government. Planning agencies and environmentalists have recognized that the quality of the environment and specifically air quality is in large part dependent upon wise land use planning. However, the role of agriculture in terms of what it can contribute to the maintenance of productive open space has not been fully recognized by the planners. Lands in close proximity to metropolitan centers have been looked upon as a potential supply for the more intensive uses while agriculture has been considered as a residual user.

Betalain pigments (red beet) were incorporated as a colorant in summer sausages formulated from 50% mechanically deboned turkey frames and 50% hand deboned turkey meat. Different levels of betalain pigments were added to sausages and compared with summer sausages formulated with or without the addition of sodium nitrite (156 p.p.m.). Addition of betalain pigments at a level of 25 p.p.m. produced a color resembling the nitrite control turkey sausages. However, to obtain a darker red color, the incorporation of 35 p.p.m. of betalain and 1.4 p.p.m. of Annatto was required. Sensory evaluations indicated a preference for sausages formulated by the addition of betalain pigments because of a desirable color in the sausages. Exposure of sausages to light resulted in lower color scores by taste panelists for the nitrite control, but did not produce any serious detrimental effects in sausages with added colorants.

Summer sausages were formulated from mechanically deboned chicken meat (MDCM) using broiler necks and backs with the addition of different proportions of ground beef and/or hand deboned broiler meat from whole carcasses. Centrifuged MDCM and various additives were also evaluated. Both subjective and objective techniques were used to analyze the products. The results indicated that hand deboned broiler meat from whole carcasses failed to provide a satisfactory cure color, but incorporation of MDCM in the formulations greatly enhanced color development. When MDCM was mixed with ground beef in various combinations up to a 50% level, an acceptable product with good color, firmness and texture was obtained. Higher percentages of MDCM above 65% resulted in a product with good color, but a softer texture. Incorporation of centrifuged MDCM and the additives improved the products slightly when compared with controls.

Summer sausages formulated from 50% mechanically deboned chicken meat and 50% ground beef (50/50 MDCM/Beef), 50% mechanically deboned turkey meat and 50% ground beef (50/50 MDTM/Beef) and from 100% ground beef were tested for their overall quality measurements after storage at two different temperatures (20°C. and 4°C.) subsequent to mellowing for 7 days in a 4°C. cold room. Sausages were examined at 0 time and after 5 days, 10 days, and 15 days and measured for weight loss, shear value, sliceability, pH, shrink, TBA value, and color. Subjective preference taste panel scores by semi-trained members were obtained. Summer sausages were also formulated from meat samples which were in frozen storage for 3 or 6 months and tested similarly as to their acceptance. The loss in weight was higher for the treatments held at 20°C. than at 4°C. and greater during the first 5 days of storage. The overall shrinkage observed was higher in MDCM and MDTM sausages than in the 100% ground beef sausages held at 20°C.; less shrinkage was observed in sausages held at 4°C. Shear values and sliceability scores of MDCM and MDTM increased with length of storage showing an increase in firmness, but this was not observed in the 100% beef sausage treatment. Sausages were found quite acceptable when formulated from meats which had undergone 3 and 6 months of frozen storage. However, TBA numbers of the sausages made from the frozen stored meats were higher than those encountered in the sausages stored as such for 15 days.

Mechanically deboned chicken meat (MDCM), centrifuged mechanically deboned chicken meat (MDCMc), hand deboned broiler meat (HDCM), mechanically deboned turkey meat (MDTM), centrifuged mechanically deboned turkey meat (MDTMc), and ground beef were stored frozen for a 6-month period at −25°C. Meats were taken out from frozen storage immediately after freezing and after 1 month, 3 months and 6 months, and measured for color change, water holding capacity (WHC), emulsifying capacity (EC), and 2-thiobarbituric acid value (TBA). Proximate analyses were conducted at the beginning and end of the experiment. Relatively few changes in the meats were seen as a result of storage time. The intensity of redness was found highest in ground beef, but some color was lost as a result of prolonged storage. Non-centrifuged meats had higher redness scores than centrifuged meats. Centrifugation of MDCM and MDTM improved both the WHC and EC of the respective samples. The EC of HDCM was quite high, but the WHC was low. Ground beef possessed an excellent WHC and EC initially, but EC declined during storage. Most of the significant changes in meat quality due to storage time were decreases in redness and EC declines. Results generally indicate that the meats studied in this research can be stored frozen at −25°C. for up to 6 months and still be acceptable for use in emulsion products.

Amorphous (and partly micro-crystalline) aluminium hydroxide precipitates were prepared by controlled hydrolysis of aluminium isopropoxide and aluminium sulphate solutions: the kinetics of their dissolution in well-stirred sodium hydroxide solutions (0.25 to 3 g ion/l) in large excess was studied at 5° to 35°C.

1. Aneuploids of Collinsia heterophylla Buist (n = 7) with three (trisome) to seven (heptasome) replicate chromosomes could not be distinguished from each other or from diploids by any detectable alteration in gross morphology. 2. The extra chromosome in trisomes always occurred as a univalent at metaphase I; bivalents and univalents were observed in tetrasomes; multivalents were noted in pentasomes and polyploids. 3. The extra chromosome was transmitted by the pollen from trisomics with a frequency ranging from 25 to 65%; except in one line, pollen from tetrasomics usually had n + 1 chromosomes; pollen with n + 2 or n + 3 chromosomes was produced by aneuploids with more than two extra chromosomes. 4. Trisomics used as seed-parents yielded tetrasomics, the frequency being determined by the specific line; progenies from tetrasomic seed-parents included numerous tetrasomics. 5. Heptasomes (2n + 5) represented the upper limit of the number of replicate chromosomes in a plant. 6. Progenies from certain self-p...

SUMMARYEight hundred and ninety-eight records of the interval between calving and conception (service period) of 349 Hariana cows, the progeny of 79 sires, were analysed by fitting constants for the effects of year, month of calving, calving sequence, sex of the calf, weight of the cow at calving and weight of the calf at birth. The average service period was 272·7 days with a coefficient of variability of 50·7%.The service period was longest after the first calving. Animals calving in the months of February to August had a longer service period than those calving during the months of September to January. Heavier cows tended to have a shorter service period. Sex of the calf, calving sequence and birth weight of the calf did not affect this trait significantly.Heritability of service period estimated from the paternal half-sib correlation using repeated records was 0·06 ± 0·018 and repeatability was 0·250 ± 0·039. It seems likely therefore that a shortening of the service period may not be possible through direct selection.

Heterocaryons involving nutritionally deficient mutant strains of Gibberella fujikuroi and mutant strains of this species and of four formae of Fusarium oxysporum were obtained. It was not possible to get heterocaryons of G. fujikuroi and F. oxysporum f. pisi until the latter mutant strain was adapted to grow on minimal medium. Spores from heterocaryons had either the genotype of only one component strain or of either component strain, depending on the heterocaryon. It was possible to alter nuclear ratios by growing certain heterocaryons on minimal medium supplemented with the compound(s) required by one or the other component strain. Sectors from certain heterocaryons grown on potato dextrose agar were homocaryotic for the nutritional requirement(s) of one component strain. Heterocaryosis as a taxonomic tool and the difficulties involved in demonstrating the parasexual cycle in the genus Fusarium are discussed.

Coliphage content of sewage collected from 11 different localities in Hong Kong was determined. The number of plaque-forming units (PFU) ranged from 0.036 × 10 3 to 15.9 × 10 3 per ml. In general, urban sewage tended to be richer than rural sewage both in PFU count as well as plaque morphological variation. Seventy-seven isolates were subjected to a host range study. Fifty per cent of these were able to grow on Escherichia coli K-12 as well as E. coli B. Approximately 32% were found to be male specific, and the remaining 18% were K-12 specific although sex-indifferent.

Aluminium hydroxide gels were recrystallised in high pH solution for 2–1000 h to give a series of Gibbsite powdersP11/2,P11/8,P1/48,P11/360 andP11/X, consisting of hexagonal platelet crystals; their average platelet lengths (l 0) were 0.03, 0.06, 0.13, 0.26 and 0.45 microns. The dissolution of dilute suspensions of these powders in well-stirred sodium hydroxide solutions were studied at 20–65°C Reaction solid and solution were analysed after different times by chemical and physical methods. Reaction occurred by two-directional dissolution of the platelet crystals. The reactions of GibbsiteP11/X (prepared by prolonged 1000 h crystallisation) were first order w.r.t. powder weight (and second order w.r.t. powder effective surface area); the reactions of the other Gibbsites were first order for the first twenty percent rapid dissolution and then slower. The initial rate constantsk w1 (h−1) and half-lifest 0.5 (h) for reactions ofP11/2,P11/8,P11/48.P11/360 andP11/X with sodium hydroxide solution of unit mean ionic activity at 20°C were 1.70, 0.9; 0.60, 2.2; 0.22, 5.5; 0.07, 14 and 0.02, 38 respectively. Rate constants increased linearly with the mean ionic activity of the hydroxide solution and increased exponentially with reciprocal absolute temperature, four to five times for 15°C temperature rise. Half-lifes decreased in a similar manner. Energies of activation varied from 76–83 kJ/mol. The rates of dissolution are determined by the rate of the chemical reaction between adsorbed hydroxyl ions and adjacent reactive aluminium hydroxide sites on the powder crystal surface.

The convergence proof of plate eigenvalue solution from conforming displacement finite elements is presented. The analysis is based on converting a thick plate free vibration problem in to a corresponding isoperimetric variational problem. A conforming thick, plate element is used to illustrate the mathematical development. On the basis of the derived asymptotic rate of convergence of the approximate eigenvalues, the authors propose a practical method of improving the numerical solutions. Extension of the mathematical proof to cover classical thin plate finite elements is briefly discussed.

1. Thirty interspecific hybridizations involving thirteen species of Collinsia Nutt. (Scrophulariaceae) were attempted; eighteen yielded seed that germinated. 2. Seed from crosses between C. bruceae and either C. bartsiaefolia or C. austromontana yielded dwarf seedlings which died before flowering; seed from the cross between C. bruceae and C. concolor gave many dwarf seedlings which died before flowering, though some survived. 3. Except for a triploid hybrid from the cross between C. austromontana and C. solitaria and for a trisomic hybrid from the cross between C. heterophylla and "C. bartsiaefolia" and from the cross between C. austromontana and "C. bartsiaefolia," the interspecific hybrids were diploid. 4. Hybrids within the group including C. concolor and the two collections assigned to C. bartsiaefolia and the hybrid between C. corymbosa and "C. bartsiaefolia" were fertile; the remaining hybrids did not set seed when self-pollinated. Several hybrids had aborted anthers which precluded self-pollinati...

γ-, κ-, and α- Alumina powders, prepared from gibbsite (S0= 0·4 m.2/g.), react with excess of well stirred hydroxide solutions (1–16M) according to a second-order reaction with respect to powder weight (that is, third order in powder surface area).The rate constants vary with (a±)½ according to a Langmuir-type adsorption isotherm and also with aw. For α-alumina, kw,1=ca. 0·001 g.–1 hr.–1 at 115°. For κ-alumina, kw,1= 0·018 g.–1 hr–1. at 85°, 0·053 at 100°, and 0·180 at 115°. For γ-alumina kw,1 0·05 g–1. hr.–1 at 85°, 0·20 at 100°, and 0·46 at 115°. The energy of activation for the reactions is for γ-alumina, 20,200; for κ-alumina, 22,000; and for α-alumina ca. 27,000 cal./mole. The kinetics suggest that the rate-determining step for dissolution of aluminas is a reaction between a hydrated defect region on the alumina surface and two hydroxyl ions, simultaneously weakly chemisorbed (near this region): additional water molecules may also participate in the reaction. Reaction mechanisms are discussed.

Autotetraploidy was induced in Phlox drummondii by treatment of shoot apices of seedlings with 0.5% emulsion of colchicine in lanolin. Autotetraploid plants were found to show gigantism, both at the cellular level as well as the organ level. Pollen mother cells of autotetraploid plants showed predominantly bivalents and quadrivalents. Although pollen abortion in autotetraploids was only slight, seed set of such plants was markedly reduced. Possible mechanisms for the reduced seed set are discussed.

Fertile hybrids with an interchange complex of six chromosomes from crosses between C. corymbosa and either C. tinctoria or C. multicolor yielded progeny with bivalents in the F2 and F3 generations. Two lines from the former hybrid had a “new” genome simulating the one in C. multicolor. Of the three lines from the latter hybrid, one had a “new” genome simulating the one in C. heterophylla and the others had a genome corresponding to the one in one or the other parental species.Chromosome associations in hybrids involving the lines from each interspecific hybrid and either a parental or a non-parental species were the same as those previously observed when these species were hybridized with species having a genome corresponding to the one in each line. The fertility or sterility of hybrids involving each line agreed with expectations based on previous observations on interspecific hybrids.Certain morphological observations on the lines from the interspecific observations were in accord with those made in species whose genomes were presumably present in each line. The line from C. corymbosa×C. multicolor which simulated the latter species in having its genome and the long flowerpedicel associated with this species included a large number of morphological characters from C. corymbosa.The origin of “new” genomes from the two interspecific hybrids has not yet been explained. Furthermore, it is not yet possible to determine if the genomes from these interspecific hybrids are structurally identical either with those being simulated or with those corresponding to a parental species.

The periodic field dependence of magnetic anisotropy (de Haas-van Alphen effect) has been studied for bismuth and zinc crystals by the torque method between about 1.5 and 32 kG at 4.19 degrees K and about 1.5 degrees K; in each case the orientation was chosen so that only a single fundamental periodicity was present. Particular attention was paid to the phase and harmonic content of the oscillations and to the form of the field dependence of amplitude. For bismuth good agreement was found with the theoretical formula except that the signs of the fundamental and the odd harmonics had to be reversed. For zinc the field dependence of amplitude at high fields was quite at variance with the theoretical formula and (probably in consequence) the harmonics were much weaker than in bismuth; the phases of the fundamental and the first harmonic were quite different from those of the theoretical formula. A slight field dependence was found for bismuth even at 85 degrees K, similar to the rather more marked one previously found in zinc. Oscillations of very much shorter period than the main ones were observed in zinc at the highest fields and their characteristics were briefly studied. Qualitative observations were made of the very short-period oscillations in a lead crystal, previously only observed by an impulsive method at much higher fields. No oscillations could be detected in copper, silver or gold crystals.

Summary. The root and shoot growth of oat (Avena saliva L.) and squash (Cucurbita maxima Duchesne) was reduced in proportion to propachlor concentration. Corn (Zea mays L.) root growth was inhibited only by concentrations of 16 ppm and higher. Cell division in onion (Allium cepa L.) root tips was reduced by propachlor and totally inhibited by 16 ppm. Auxin-induced cell elongation of oat coleoptiles was inhibited in proportion to propachlor concentration. Propachlor treatment prevented the normal senescence of squash cotyledons by inhibiting the autolysis of proteinaceous and lipid reserves. Effets morphologiques, anatomiques et biochimiques du propachlore sur la croissance des plantules Riisumi. Resume. La croissance des racines et des tiges de l'avoine (Avena saliva L.) et de la courge (Cucurbita maxima Duchesne) a ete reduite en fonction de la concentration du propachlore. La croissance des racines de mais (Zea mays L.) a ete inhibee seulement par des concentrations Agates ou superieures a 16 ppm. La division des cellules des extremitees des racines de l'oignon (Allium cepa L.) a ete reduite par le propachlore et totalementinhibes par 16 ppm. L'elongation induite par l'auxine des cellules des coleoptiles d'avoine a ete inhibee en fonction de la concentration du propachlore. Le traitement au propachlore a empeche la senescence normale des cotyledons de la courge par inhibition de l'autolyse des reserves proteiques et lipidiques. Morphologische, anatomische und biochemische Wirkungen von Propachlor auf das Keimlingswachstum Zusammenfassung. Die Starke der Hemmung des Wurzei- und Sprosswachstums bei Hafer (Avena sativa L.) und Squash (Cucurbita maxima Duchesne) entsprach der Propachlorkonzentration. Das Wurzelwachstum von Mais (Zea mays L.) wurde nur durch Konzentrationen von 16 ppm oder hoher gehemmt. Die Zellteilung in Wurzelspitzen der Zwiebel (Allium cepa L.) wurde durch Propachlor vermindert und bei 16 ppm vollstandig gehemmt. Die Hemmung der auxininduzierten Zellstreckung bei Haferkoleoptilen entsprach der Propachlorkonzentration. Die Behandlung mit Propachlor verhinderte die normale Alterung von Squashkotyledonen, indem sie die Autolyse von Protein- und Lipidreservcn hemmte.

The two major capital market reforms of (i) entry of Foreign Institutional Investors (FIIs) in Indian stock market (ii) permission to Indian companies for raising capital from foreign stock exchanges by means of American Depository Receipts (ADRs) / Global Depository Receipts (GDRs). Further introduction of two-way fungibility in these instruments of ADRs / GDRs leads to reduction of the sovereignty of Indian stock market. As such, Indian stock market now, is not only sensitive to national events but also more sensitive to international events. Due to the speculative motive of FIIs investment, investment by FIIs is subject to frequent reversals. Volatility is a measure of how far the current price of an asset deviates from its average past prices. Investors demand higher risk premium as a compensation for increased risk due to volatility. A higher risk premium implies higher cost of capital and thus lowers investment. The prevailing inefficiency in emerging securities markets including India further magnifies the problem of volatility. In this paper, an effort is made to predict stock return volatility and contribution of FIIs investment to that volatility using high frequency data (daily data).

Association between protein content and a gene for grain colour in Triticum aestivum L. was studied using partially isogenic populations developed from F2 plants heterozygous for a locus controlling grain colour. The dominant allelomorph (R) was found to be associated with higher protein content. The cause of the association seemed to be due to linkage between this locus and genes controlling protein content.

Biological properties of a temperate phage, HK239, isolated from cow dung were studied. This phage produces clear plaques on E. coli B and most strains of E. coli K-12, but produces turbid centered plaques on K-12 strain HfrC and E. coli C strain, CIa. Bacterial growth in turbid centered plaques on CIa and HfrC is due to lysogenic, immune bacteria. Delayed bacterial growth in clear plaques on K-12 strains is mostly that of phage resistant clones and, infrequently, of lysogenic, immune cells. HK239 shows an interesting combination of properties of two well known coliphages. It bears a close resemblance to phage P2 in its antigenic properties and in interfering with the growth of λ. On the other hand, K-12 strains lysogenic for HK239 exclude r ll mutants of phage T4 and in this respect, HK239 resembles λ.

The first spontaneous reciprocal translocation detected in a wild population of Collinsia was found in C. parryi. The interchange complex occurred as a ring or chain of four chromosomes at metaphase I and displayed an alternate or adjacent configuration in approximately equal frequencies at this stage. Crosses involving plants with an interchange complex gave progeny with only bivalents or an interchange complex in approximately equal frequencies. These observations suggest that the breaks probably occurred within the intervening segment of nonhomologous chromosomes and close to one of the chiasma-forming segments in each chromosome arm.

Distribution and degradation of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at 5, 10, 15, and 20 ppmw in red pine (Pinus resinosa Ait.) seedlings were investigated using 14C-ring-labeled simazine dispersed in agar medium. Simazine readily entered red pine roots and moved rapidly into stem and needles. Accumulation was greatest in roots, next in stems, and least in needles. Significant differences in simazine uptake by roots were observed among concentrations between 5 and 20 ppmw in the incubation medium. Radiochromatographic scans revealed that a small amount of simazine was degraded to three unknown compounds by both fresh and boiled homogenates from whole plants, needles, stems, and roots. There were no observable differences in the amount of simazine degraded by homogenates of each separate plant part.

DHILLON, T. S., and E. D. GARBER. (U. Chicago, Chicago, Ill.) The genus Collinsia. XVI. Supernumerary chromosomes. Amer. Jour. Bot. 49(2): 168-170. 1962.-The pairing and transmission of supernumerary chromosomes in Collinsia solitaria and in hybrids between C. sparsiflora subsp. arvensis and C. bruceae were studied. Two supernumerary chromosomes usually formed a bivalent with 1 chiasma at metaphase I; 4 supernumerary chromosomes occasionally yielded a trivalent and univalent at this stage. Plants with 2-4 supernumerary chromosomes were fertile and plants with 5-8, sterile. Plants with a given number of supernumerary chromosomes when used as seed or pollen parent gave gametes with a higher number of such chromosomes. SUPERNUMERARY chromosomes have been reported in many plant species (Darlington and Wylie, 1956). According to White (1954), they are chromosomes which may be present in addition to those of the normal complement. Although they usually share a number of characters, neither their origin nor their function, at least in plants, has been satisfactorily resolved (Swanson, 1957). In general, supernumerary chromosomes are shorter than the shortest chromosome of the complement and are largely, if not completely, heterochromatic. Although supernumerary chromosomes pair with each other, they do not pair with any chromosomes of the complement. According to Lewis (1951), supernumerary chromosomes in Clarkia elegans cannot be distinguished from the normal complement on the basis of meiotic behavior or staining. Lewis states: "There can be but little question that supernumerary chromosomes are being formed in certain populations of Clarkia and Godetia at the present time, and that these supernumerary chromosomes represent duplications of chromosomes that are members of basic genomes." Plants with relatively few such chromosomes usually do not display an obvious phenotypic alteration. The minimum number of supernumerary chromosomes leading to sterility depends on the species. According to Paliwal and Hyde (1959), a single supernumerary chromosome in Plantago coronopus was responsible for male but not for female sterility. Consequently, the maximum number of supernumerary chromosomes in an individual may be different for different species or genera. Populations within a species may or may not include individuals with one or more such chromosomes. Finally, the number of supernumerary chromosomes may increise during gametogenesis, usually microsporogenesis. Supernumerary chromosomes have been reported in Collinsia solitaria Kell (Garber, 1958) and in hybrids between C. sparsiflora Fisch. & Mey. subsp. 1 Received for publication July 12, 1961. This investigation was aided by grants from the National Science Foundation and from the Dr. Wallace and Clara A. Abbott Memorial Fund, University of Chicago. 2 Current address: Department of Botany, University of Hong Kong. arvensis (Greene) Jepson and C. bruceae M. E. Jones (Ahloowalia and Garber, 1961). These chromosomes were smaller and stained more darkly at metaphase I than the chromosomes of the complement (n 7). An extensive survey of the genus Collinsia has not yet revealed supernumerary chromosomes in species other than those which have been mentioned (Garber, 1956, 1958). According to Ahloowalia and Garber (1961), C. solitaria, C. sparsiflora, and C. bruceae constitute a group of very closely related species which yield fertile interspecific hybrids. This report presents data indicating that supernumerary chromosomes in the genus Collinsia differ from those in other plant species with respect to their transmission. MATERIALS AND METHODS-Plants of C. solitaria, C. sparsiflora subsp. arvensis, and C. bruceae were grown from seed collected in California by Dr. R. Bacigalupi. Supernumerary chromosomes were observed in pollen mother cells of 1 plant of the former species and of 1 hybridbetween the latter species. Plants with supernumerary chromosomes were self-pollinated and crossed with plants lacking such chromosomes and the progenies were studied. Procedures for germinating seed, raising plants in the greenhouse, fixing anthers, staining smears of pollen mother cells with acetocarmine, and determining fertility have been presented in earlier papers (Garber, 1956; Garber and Gorsic, 1956; Soriano, 1957). Poor germination of seed was responsible either for the relatively small populations available for study or for the absence of plants from certain self-pollinations and hybridizations. RESULTS --The supernumerary chromosomes never paired with any chromosomes of the complement. In 1 of 115 pollen mother cells from 4 plants with 2 supernumerary chromosomes, these chromosomes occurred as univalents; in the remaining cells, the supernumerary chromosomes occurred as a rod-bivalent, indicating 1 chiasma per bivalent. In plants with 4 such chromosomes, they usually formed 2 rod-bivalents, but 1 rod-bivalent and 2 univalents or a trivalent and a univalent were not uncommon (Table 1). Laggard supernumerary

Host resistance to infection was measured by the in vivo response to 5 delayed hypersensitivity antigens and to sensitivity and challenge by dinitrochlorobenzene (DNCB) in 55 seriously ill or injured patients and in 50 preoperative patients. A close correlation between infections, septicemia, death related to infection and anergy was found in the postoperative and post injury patients and was predictive of these complications in the patients studied preoperatively. Decreased body cell mass was noted in both the anergic and non-anergic patients which was consistent with protein-calorie malnutrition but the two groups were not significantly different. A serum factor which inhibited cellular immunity in vitro was found in 4 patients. This factor disappeared in the two patients who recovered. The study suggests the therapeutic value of the in vivo measurement of delayed hypersensitivity in seriously ill and especially preoperative patients in whom specific or non-specific stimulation of cell mediated immunity might alter the risk of infection.