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1. The malarial parasite is extracellular throughout its entire life cycle; that is, when it is not free in the blood serum, it is attached to the external surface of the red corpuscle. 2. Adult parasites follow the same procedure in attaching themselves to the outer surface of the red corpuscles as do the young parasites. 3. Adult parasites are most frequently seen attached to surface corpuscular mounds. 4. Corpuscular mounds projecting at the periphery of the red corpuscles and encircled by the pseudopodia of adult parasites, are proof positive of the extracellular relation of the adult parasite to the red corpuscle. 5. Adult parasites attached to peripheral corpuscular mounds are only found in appreciable numbers when the red corpuscles are not badly damaged, so that the mounds show more or less hemoglobin content. 6. The nuclei or protoplasm of adult parasites extending beyond the periphery of the red corpuscles is additional evidence of the extracellular relation of the parasites to the red corpuscle.

The author, after paying tribute to the late chief of the NIMH training branch, describes past and current psychiatric education. Among the contributions he believes psychiatry has made to medical education are its emphasis on methods of observation and on understanding the personality. However, he believes current psychiatric training has neglected contributions from the biological sciences and fails to completely recognize the importance of the entire life cycle. He also assesses recent changes in medical school curricula.

A one-and-a-half-dimensional, time-dependent cloud model proposed by the authors is extended to investigate warm-rain formation. A total of 61 mass categories, corresponding to radii from 4 μm to 4 mm, are used to determine the drop distribution. The distribution of hydrometeors evolves with time as a result of condensation, evaporation, stochastic coalescence, sedimentation, and drop breakup. The formation of liquid drops around condensation nuclei is parameterized to take a prescribed drop size distribution, though the number concentration of nuclei is predicted. Three different types of the prescribed initial size distribution of drops are considered to test their control of the subsequent hydrometeor distribution. Convection is initiated in a conditionally unstable atmosphere which represents tradewind conditions, and long time integrations of the model are performed to cover the entire life cycle of a simulated cumulus cloud. In a typical case, the maximal updraft resulting from the calculat...

1. 1. The total lipid and the phospholipid of the house cricket, Acheta domesticus (L.), were studied during its entire life cycle. 2. 2. Total lipid decreased during the egg and early larval stages, then rose steadily during the remainder of larval life. Total lipid in adult males gradually declined with age, while in the females the total lipid decreased during the first 3 weeks, then increased slightly. 3. 3. Phospholipid remained more or less contant during the entire life cycle. Phosphatidylcholine and sphingomyelin showed cyclical patterns of change during the life cycle, whereas phosphatidylethanolamine was constant during the egg stage and, at a higher level, constant during postembryonic life.

Larval and pupal stages of Psephenivorus mexicanus Burks are described and figured, and observations upon adult behavior are presented. The wasp utilizes prepupal and pupal hosts, as many as 39 wasps developing within a single host. The entire life cycle may be completed within 21 days. In the region of Sabinas Hidalgo, Nuevo Leon, Mexico, more than half of the pupal hosts found were parasitized and destroyed by Psephenivorus. The known host is Psephenus texanus Brown & Arrington, but other species such as P. palpalis Champion may be used. Attempts to find parasites in North American psephenids have thus far been unsuccessful, except in the vicinity of Del Rio, Texas.

The effect of chronic irradiation was studied on flax plants subjected to exposure rates ranging from 100 R to 1000 R per 20-hr day throughout their life cycle in the 60 Co gamma field. There was a significant increase in plant height at exposure rates from 400 R to 800 R/day, and in the number of primary branches at exposure rates from 300 R/day to 1000 R/day. The seed yield per plant at 100 R/day and 200 R/day was significantly higher than that of the non-irradiated plants, and this increase was due to an increase in the number of capsules per plant, although the number of seeds per capsule decreased constantly with increasing radiation exposures. Dry seeds of flax were subjected to 60 Co gamma irradiation with exposures ranging from 10 kR to 250 kR, and the effects on morphological characters and yield performance were studied in the M 1 and M 2 generations along with the M 1 and M 2 generations of the chronically irradiated plants. There was a considerable increase of variability in morphological characters and seed yield in the progenies of both chronically and seed irradiated plants. A high yielding, yellow seeded mutant plant appeared in the M 2 progeny of a 600 R/day irradiated plant. About twice as much exposure of acute seed irradiation was found to produce similar damage at maturity as that produced by an accumulated exposure to chronic irradiation over the entire life cycle of the flax plants.

Results are presented on observations of the life cycle and biology of the chigger mite, Trombicula akamushi (Brumpt) reared under constant environmental conditions in the laboratory. The entire life cycle required 46 to 72 days, and data on the development of the various stages are presented. Observations made on the subsequent development of groups of larvae which had been fed on rodents or on chicks indicated that engorgement on the former led to more rapid development. Of particular interest were observations made on sex determination, which indicated that while some females produced both male and female offspring, most females produced offspring of only one given sex.

Eggs of Simyra henrici (Grote) had incubation periods ranging from 20 days at 14.4°C to 3 days at 32.2°C. Developmental velocity was a straight-line relationship. The theoretical threshold of egg development was about 11.1°C. Larval development was completed in 7 or 8 instars at temperatures from 14.4° to 32.2°C. The theoretical threshold of larval development was 10°C, and the mean degree-day requirement for completion of the larval period was 502.0. The rate of larval development also showed a straight-line relationship at these temperatures. The duration of the larval period ranged from 22.7 days at 32.2°C to 56.7 days at 18.3°C for larvae having 7 instars and from 24.3 to 62.7 at these same temperatures for larvae having 8 instars. The combined prepupal and pupal periods ranged from 11 days at 32.2°C to 42 days at 15.6°C with a degree-day requirement of 248.3°C based on the 10°C threshold temperatures. The entire life cycle of S. henrici ranged from 37.5 days at 32.2°C to 97.2 days at 18.3°C with a mean degree-day requirement of 806.9 over the 10°C threshold. S. henrici overwinter as pupae, and the supercooling points of 11 pupae ranged from -21.1° to -27.8°C. Pupae exposed to natural outdoor conditions had a mean survival rate of 15.5% in 1964-65. The severity of winter greatly influenced the number of S. henrici adults present the following summer.

To improve the effectiveness of the soybeans and oil flax breeding, research to improve existing and develop new breeding methods are conducting in all-Russia Research institute of Oil Crops (Krasnodar). One of the improved methods for the soybean breeding, based on the use of sources of complexes of compensatory genes, is the CCG technology, which allows to create varieties with an increased yield of a heterotic level transmitted along the progeny for the entire life cycle of the variety. For the purpose of non-transgenic production of new traits, a theory of polyploid recombination of the genome (TPR) was formulated, which models the mechanism of the natural formation of polymorphism in the centers of origin of cultivated plants. On the basis of this theory, a method of breeding (TPR-technology) has been developed, which makes it possible to obtain recombinant reploids of soybeans and oil flax with an extended spectrum of traits. Of these reploids, the soybean lines with increased sucking force of the roots, providing high drought resistance, were distinguished; cold-resistant soybean lines, which stand in the phase of shoots of freezing to minus 5 °С; lines of oil flax with complete resistance to flax sickness of soil and high resistance to Fusarium; winter-hardy flax lines that withstand winter frosts down to minus 20–23 °С and ripen one and a half months earlier than spring sowings. Another original developed method is the ODCS-technology for isolating and selecting soybean genotypes with high resistance to fungal pathogens. The physiological basis of ODCS-technology is the blocking of osmotic nutrition of pathogenic fungi due to genetically determined increased osmotic pressure in the tissues of host plants. The practical implementation of CCG-, TPR- and ODKS-technologies in the selection process, allowed to create a whole series of soybean and oil flax varieties with improved or new traits.

II. COMING now to the large and important question of the Conjugation of Infusoria, its nature and bearing upon the life-history of the forms, we are bound to state at once our conviction of the inefficiency of the observations recorded on account of their discontinuity. Nothing but a close and continuous observation of the same forms extending over an entire life cycle, repeated again and again, can lead to absolute results. Errors fatal to the interests of truth inevitably arise, when minute organic forms are studied, not by continuous watching, but from inferences made from the phenomena manifest at different periods, the intervals between which are blank. Further, whilst the use of reagents on the dead forms taken at various stages is of the utmost value, when they are examined side by side with continuous observation on the living form, these may be not only not instructive but misleading when taken by themselves. Butschli on the Earliest Developmental Processes of the Ovum, and on the Conjugation of Infusoria. Studien uber die ersten Entwicklungsvorgange der Eizelle, die Zelltheilung und die Conjugation der Infusorien. Von O. Butschli. (Frankfurt, 1876.).

Heavy losses of largemouth bass fingerlings at the Jonkershoek Inland Fish Hatchery, Stellenbosch, South Africa, were attributed to heavy infestation of the ureters with a gyrodactyloid parasite closely related to Acolpenteron ureterocoetes. The parasite has no intermediate host, and in heavily infested fish may complete its entire life cycle in the ureters. Infected fish display inflammation of the kidneys, ureters, and urinary openings and, in acute cases, great abdominal distension anterior to the cloaca. Some diseased fish die gradually, others in convulsive spasms. This disease occurs only in fish reared on artificial food in concrete rearing tanks. The spread of the disease can be checked by transferring fish from such small tanks to fertilized open ponds, where natural food and absence of crowding usually alleviate the condition. It is recommended that largemouth bass be reared to the fingerling stage in fertilized earthen ponds 0.1 acre or more in size, stocked at the rate of 12,000 advan...

It has been possible for some time to grow the entire life cycle of Neoaplectana glaseri,1 a nematode parasite of the Japanese beetle, in cultures in which bacterial and fungous growths have been inhibited in various ways but not eliminated.2 These contaminants undoubtedly introduced a high degree of variability into the results obtained. It therefore seemed advisable to attempt to rear this parasite in cultures free from bacteria.Lapage3 and Glaser and Stoll4 developed technics whereby the second ecdysis of strongyloid nematode larvae was easily and consistently obtained in quantity under sterile conditions. It was found necessary to modify one of these technics slightly for work with Neoaplectana. Cultures prepared in the routine manner were permitted to develop for 10 to 15 days, at which time the majority of the parasites were second-stage larval forms in their third or fourth generation.∗ These were removed from the surface of the solid medium and washed with water until free of much debris. To remov...

Previous studies on the vitality of Uroleptus mobilis have shown that all ex-conjugants start with an initial high vitality as measured by the division rate. From this initial high rate, vitality gradually decreases during the life cycle until the race dies a natural death. After the first fifty days of a cycle endogamous conjugation may occur at any time with a resulting renewal of vitality in the ex-conjugants. Sufficient data have now been obtained to indicate that there is a difference in vitality of offspring given off at different age periods of the parental series, and a summary of such data is shown in the accompanying table.Line 1 gives the total number of generations, or divisions, in in each series; line 2 the total number of days required for those divisions; line 3, compared with line 5, indicates the extent of the renewal of vitality resulting from conjugation; line 4 gives the average division rate for any ten days of the entire life cycle on the assumption that divisions are equally distri...

A method is described for raising sea urchins from egg to egg in the laboratory. The larvae are raised on flagellated marine algae and the young urchins on a substrate-dwelling diatom. The major features in the developmental process are: growth of the larva, development of the urchin inside the larva, metamorphosis and growth of the young urchin to sexual maturity. The entire life cycle takes about six months.

Although classical work continues, particularly on the trematodes, for the most part the basic life cycle patterns must be regarded as worked out. Helminthologists are increasingly turning attention to the mechanics of the life cycle with the result that parasitology is becoming an experimental science. Worms are now under study from the biochemical, physiological, and behavioral points of view. As a result, ideas of specificity have been altered, new physiological races of parasites discovered, and a number of new human helminthiases recognized, chiefly zoonotic and involving larval forms. The number of parasitic worms successfully adapted to laboratory propagation in animal hosts steadily increases, providing new and fruitful models for investigation. Even more striking is the great breakthrough in the last decade involving in vitro culture. Several cestodes and a variety of nematodes can now be reared through various stages, if not their entire life cycle, in partially defined media, and progress is being made with trematodes and acanthocephalans. Behavioral studies are beginning to shed light on how parasites find their hosts and how they locate each other inside the host. And in spite of long-held views to the contrary, evidence increases that certain activities of helminths may be under hormonal control.

Social work, in order to expand its knowl edge base, has borrowed liberally from the concepts of psychiatry, medicine, and the social sciences. This paper suggests the possibility that a fresh perspective might be obtained through use of concepts from a natural science, ethology.1 Ethology is an objective study of behavior that goes be yond the usual naturalistic approach. Ethologists begin their study by obtaining as complete knowledge as possible of the behavior of a species during its entire life cycle in order to classify and compare the behavior of different species, especially re lated ones.

The differentiation and degeneration of the cement gland in Xenopus laevis is described. The gland is first observed histologically at stage 19 (neural tube stage) as a packed group of apical ectoderm cells heavily laden with oocyte pigment granules, lying ventral to the cranial neural fold. By tailbud stage 35/36, the gland cells have increased in height and are approximately ten times taller than nonglandular apical ectoderm cells. The nuclei divide the gland cells into an apical region that is eosinophilic and contains oocyte pigment granules, and a basal region that contains clear droplets. The cells are decreasing in height by stage 40 (early tadpole) and begin to lose their pigment granules. Between stages 45 and 48, the pigment is extruded and the clear basal droplets diminish in number. From stage 48 to 49 the cells become vacuolated and the histotypic characteristics of the functional gland are lost. The gland is not vascularized, nor do phagocytic cells appear in its vicinity during any stage of its development. It remains bordered at its base by subjacent basal ectoderm during its entire life cycle of 10 to 12 days at room temperature.

Tropical cattle ticks (Boophilus microplus) seeded as larvae on penned white-tailed deer (Odocoileus virginianus) completed the entire life cycle on the deer. It has long been known that the tropical cattle tick (cattle fever tick) is sometimes found on white-tailed deer. (For example see Shillinger, J. E. 1938. Deer in relation to fever tick eradication in Florida. Trans. N. Am. Wildl. Conf. 3:882-885). Conflicting conclusions have been drawn from such field observations regarding the effect of the presence of deer where eradication of Boophilus ticks is being attempted by dipping domesThis content downloaded from 40.77.167.89 on Fri, 01 Apr 2016 05:31:54 UTC All use subject to http://about.jstor.org/terms DEER AND CATTLE FEVER TICKS * Park et al. 203 tic livestock (Marshall, C. M., G. A. Seaman, and F. A. Hayes. 1963. A critique on the tropical cattle fever tick controversy and its relationship to white-tailed deer. Trans. N. Am. Wildl. and Nat. Resources Conf. 28:225-232). In the absence of valid experimental evidence as to the relationship between tropical cattle ticks and deer, the potential for controversy increases as the values of the cattle and deer industries of the Southeast increase. The accidental reinfestation of any area of the Southeast by tropical cattle ticks and tick-borne diseases might develop into verbal and economic warfare between cattlemen and deer-loving sportsmen if the cattlemen were to ask for elimination of the deer as a prerequisite to a tick eradication program or in conjunction with one. In May, 1962, a study with three deer, two does and a buck, was set up at the Federal Experiment station, St. Croix. These deer were placed in a small enclosure, 30 x 60 feet, and closely observed for 3 months. No ticks were seen, and we therefore concluded that the deer were free of them from