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Summary and ConclusionsVarious steroid hormones, especially D.C.A. and progesterone produce deep anesthesia in rats and mice if injected into the peritoneum whence they can be rapidly absorbed. Aft...

Sherrington1 has summarized rather completely our knowledge of tonus for smooth and striated muscle. He believes that muscle fiber is not to be considered as an elastic string, for it has the property of exhibiting different lengths with one and the same degree of tension. This doctrine is of special interest in the case of the abdominal musculature, which is of necessity subject to many changes in pressure due to the many variations which occur in the abdominal contents. We should therefore expect to find the muscle fibers of the abdomen showing different lengths with the same degree of tension, or, to put it conversely, to exhibit a fairly constant pressure with varying increments of volume.The object of these experiments has been to determine whether this regulation of inter-abdominal pressure is essentially a function of the nervous mechanism of the abdominal walls or of the intrinsic musculature itself.Cats were used in these experiments under the several conditions of light and deep anesthesia and d...

While observations on vitamin A deficiency in the dog have been reported by several investigators,1-4 no attempt to determine the dog's minimum requirement of vitamin A has appeared in the literature. This report deals with such a study.The synthetic vitamin A-free milk previously described5 was used in these experiments. In that report5 illustrations are given of xerophthalmia produced with this synthetic milk and cured by the addition of Carotene to this diet.In this group of puppies herein reported, the curative method was used. All the puppies used were started on the vitamin A-free ration at weaning, or at most, 1 or 2 weeks later. It has been found highly important to rid the animals of any intestinal parasites at the beginning of the experiment. All the animals were devocalized under deep anesthesia. The total number of puppies used was 31.The first curative levels used were based on the curative dose per 100 gm. of body weight of the albino rat. The negative results obtained with these levels resu...

Halsey and Lemann1 found that hypodermic injection of epinephrin in asthmatic patients may cause relaxation of the bronchial musculature without synchronous rise in blood pressure. This observation reopened the question of the differing sensitivity of various epinephrin receptors. C. A. Dragstedt and Huffman2 recorded in dogs the simultaneous effects of continuous intravenous injections of epinephrin on blood pressure and intestinal motility during and after anesthesia and in the absence of drugs and anesthetics. Except under deep anesthesia, the authors were able to obtain definite blood pressure rises without intestinal inhibitions. Durant and McNinch3 externalized the spleens of two young dogs by the Barcroft-Stephens method and took blood pressure and oncometric (spleen) tracings while the animals were unanesthetized. Intravenous injection of minimal amounts of epinephrin produced blood pressure rise and splenic constriction, but no intestinal inhibition.Luckhardt and Koppanyi4 developed a method whic...

ConclusionsIt was not found possible to produce a progressive decline in arterial pressure, leading to death in lightly anesthetized dogs by means of deep muscle burns alone. A prodromal state of shock was produced, however, since the resistance of these dogs to bleeding was significantly less than that of control dogs similarly anesthetized but not burned. Since the volume of blood which had to be removed from the burned dogs in order to lower their mean arterial pressure to 50 mm Hg, plus the volume of edema in the legs, was as large as or larger in each case than the bleeding volume of the corresponding control dogs, it is concluded that the accumulation of fluid at the site of the burn is the principal factor responsible for the prodromal stage of shock in the burned dogs. Association of the extensive muscle destruction with restriction of movement and with prolonged moderately deep anesthesia converts the prodromal stage into outspoken shock with death of the dog even when the accumulation of fluid a...

The following method of studying peristaltic movements of the intestines in situ has been found extremely useful by the writers in connection with an investigation of certain purgatives and is deemed worthy of description for the benefit of other investigators because it is simple, efficient and economical.A white rat, previously starved for 24 hours, is anesthetized with an intraperitoneal injection of urethane. This anesthetic has been found by the writers to act with extraordinary rapidity in the rat, so that an injection of 1.25 gm. (using a 4% solution) per kilo weight of rat produces complete and deep anesthesia within 5 minutes, lasting for 5 or more hours without any appreciable depressant effect on the heart or respiration. Doses of 1.5 gm. per kilo produce an anesthesia lasting for 24 hours or more, while 1.0 gm. per kilo produces an anesthesia of shorter duration. The rat is tied on a small dissecting board and immersed in physiological saline solution at body temperature, care being taken to k...

The authors exhibited to the society two guinea-pigs, which were deeply narcotized by injections of magnesium sulfate. One of these animals had been similarly narcotized twice before, and fully recovered each time. In their physiological and toxicological studies of magnesium salts, the authors found that by subcutaneous injections of certain quantities of sulfate or chlorid of magnesium, animals can be brought into a state of deep anesthesia, during which any operation can be performed upon them without the least resistance. If the dose of the salts is not too large, heartbeat, blood-pressure and respiration remain nearly normal. It was tested on dogs, cats, rabbits, guinea-pigs, white rats and frogs. A gram and a half of magnesium sulfate is about the effective dose for most of the animals. The chlorid has to be used in smaller doses in proportion to its smaller molecular weight. Particulars will be reported later. The authors emphasized the fact that these salts are very poisonous when certain maximum ...