PHYSIOLOGY. 



543 



The origin of the pepsin which is accreted by 

 the urine has been found by Drs. Delezenne and 

 Drouin, of Paris, to be in the gastric juice. 



, Muscular System. An investigation of the 

 isometric value of active muscle excited directly 

 and indirectly was undertaken by H. R. Dean 

 with the view of comparing the tension developed 

 in active muscle when directly stimulated and 

 when stimulated through its nerve. The conclu- 

 sion was reached that the total tension developed 

 by a muscle in response to a direct excitation is 

 greater than that which can be elicited by the 

 maximal stimulation of its nerve, and that the 

 increased mechanical efficiency of the directly ex- 

 cited muscle is not due to the summation of an 

 indirect with a direct response, or to variations in 

 the position of the starting-point of the response; 

 it is thus little influenced by such alteration in 

 the time of the active processes, as must occur 

 if the position of the starting-point is changed. 

 The result presents several points of interest in 

 connection with muscular activity, which are 

 described in the author's paper. 



The influence of the ingestion of sugar upon 

 rigor mortis was the subject of experiments by 

 Dr. Frederick Lee, of New York, and Dr. C. C. 

 Harrold, who found that the administration of 

 dextrin before their death to fasting cats which 

 had been treated with phlorizin delayed the rigor 

 of the muscles which usually ensues a few min- 

 utes afterward. Absence of carbohydrate from 

 the muscles favored the development of rigor, but 

 was unfavorable to contraction. 



The use of the telephone in investigating the 

 rhythmic phenomena of the muscles was described 

 in the British Association by Sir J. Burdon-San- 

 derson, whose paper was based largely on the re- 

 searches of Miss Florence Buchanan. 



In sixteen experiments on the effect of mus- 

 cular work upon the digestibility of food and the 

 metabolism of nitrogen carried on by Prof. C. F. 

 Wait at the University of Tennessee, it appeared 

 that, comparing the elimination of nitrogen in 

 the urine during the periods of little muscular 

 activity and normal diet with that during periods 

 of increased activity and a diet furnishng energy 

 largely in excess of the heat equivalent of the 

 measured work performed, a slight decrease took 

 place under the latter condition. This was true 

 even when the possibility of a lag of considerable 

 duration between the breaking down of nitroge- 

 nous material within the body and the excretion 

 of nitrogen in the uri,ne was admitted. 



The presence of some enzyme in muscle having 

 the power of breaking up the sugar with which 

 the muscle is supplied through the blood, and con- 

 verting this food into energy with the formation 

 of simpler organized bodies, had been suspected 

 by physiologists for some time. An experiment 

 by Brunton in 1873 which seemed to prove it was 

 liable to criticism for its method; and other ex- 

 periments reported were inexact, because the ma- 

 terial used had not been proved free from pos- 

 sible fermentative organisms. In a research de- 

 scribed by T. Lauder Brunton and Herbert Rhodes 

 before the Royal Society the muscle juice, col- 

 lected with great care, was filtered through a 

 Pasteur-Chamberland candle, the other fluids were 

 boiled, and the apparatus was disinfected by 

 steam. Two flasks were prepared, each contain- 

 ing fresh sterile muscle juice and sugar solution. 

 In one flask the muscle juice was boiled previous 

 to adding the sugar solution. After incubation 

 at body temperature, the sugar in each flask was 

 estimated quantitatively, when a very marked 

 diminution was observed in the percentage of su- 

 gar in the flask containing unboiled juice. It was 



thus shown that a substance- < i t , ; ; , tYc-h mus- 

 cle which has the power of l>re, : ,, -u^ar 

 molecules; and this su))st;ui; S 7iy, 

 partakes of the nature of a _ ! 

 Although an attempt lias hccii'mii ^hitc 

 the en/yme, it is of such a dcli<:n> n > 

 the isolating process adopted d< 

 menting powers. 



From tlie results of an investigation of 

 of the substitution of alcohol tor sugar in io 

 upon muscular action in the dog, f:;uii<<! on 

 through observations of the respiratory cocHi- 

 cient, M. A. Chauveau concludes that the alcohol 

 introduced, although very rapidly absorbed by 

 the organism, participates only to a small extent, 

 if at all, in the combustions from which the mus- 

 cular system draws the energy necessary to its 

 working. The alcohol is not an energy-producing 

 food, but its introduction into food has rather 

 the opposite effect. This effect is pronounced un- 

 favorable from all points of view, being marked 

 by a diminution in the absolute value of the mus- 

 cular work, and an increase in the food used 

 up with respect to the amount of work accom- 

 plished. 



The Nervous System. It was for a long time 

 regarded as impossible for an adult creature so 

 high in the animal kingdom as a dog to live for 

 any considerable time after being deprived of both 

 cerebral hemispheres. Prof. Goltz has, however, 

 succeeded in removing both hemispheres from a 

 dog and keeping the animal alive in this brainless 

 condition for several months. He first removed 

 the left hemisphere by two separate operations, in 

 June and November, 1889; and afterward the 

 right hemisphere, in June, 1890. The basal part 

 of the temporal lobe was allowed to remain, lest 

 the optic tracts should be injured in their re- 

 moval. The animal was finally killed, in Decem- 

 ber, 1890. Its physiological condition was de- 

 scribed by the experimenter in the German Ar- 

 chives for General Physiology, and a full abstract 

 of the paper is given in Schafer's Text-Book of 

 Physiology, vol. ii, page 302. No complete ana- 

 tomical examination of the nervous system had 

 been published till the subject was undertaken by 

 Gordon H. Holmes, who found that removal of 

 the cerebral cortex caused complete degeneration 

 in most of the cells and sclerosis in the glia of 

 the optic thalamus and diminution in the myeli- 

 nated fibers in the gray matter of the interbrain, 

 though both changes were less marked in the 

 ventral nucleus results that go far to show that 

 Goltz's hope that a subsequent operation would 

 succeed in removing the mantel and leaving the 

 interbrain in the normal state will never be real- 

 ized, so clearly is the existence of the one depend- 

 ent on the integrity of the other. Degeneration 

 \vas also observed in the cortico-spinal and cortieo- 

 pontal tracts, in all parts of the fornix which are 

 separated from the cornu ammonis, and a local- 

 ized degeneration in the corpora-mammillaria. Re- 

 moval of the cortex had no appreciable influence 

 on the corpus striatum or the radiatio strio- 

 thalamia, but the latter tract degenerated when 

 the corpus striatum was injured, and proportion- 

 ately to the extent of the injury. Great degenera- 

 tion was caused in certain nerve-cells of the pri- 

 mary optic centers viz., the pulvinar lateral 

 geniculate bodies and anterior quadrigeminal 

 bodies, but the splittings up of the optic fibers 

 within the gray masses remained unaffected, 

 and no appreciable changes occurred in the optic 

 tracts or nerves which could be attributed to this 

 degeneration. As a whole, the parts of the brain 

 of the animal which degenerated on removal of 

 the cerebral cortex were those which are not repre- 



