560 



PHYSIOLOGY. 



presence of urea has a marked accelerating effect, 

 greater as the amount increases up to about 

 10 per cent., upon the digestion of fibrin by pepsin, 

 HC1 (0.3 per cent. HC1), or by trypsin. In much 

 larger quantities it has a retarding influence. 

 A saturated solution of urea is a valuable histo- 

 logical reagent. By its reaction on the connect- 

 ive tissues it greatly facilitates the separation of 

 a tissue into its individual elements that is, car- 

 diac and skeletal muscle, lens-fibers, fat cells 

 and except in the case of the connective tissue 

 and possibly of the nerve-fiber, there is no danger 

 of its action being too energetic or going too far. 

 The properties of urea combined with palmitic 

 acid are considered in the paper. The basic char- 

 acter of urea shown by its combinations with vari- 

 ous acids suggests that it is acting as a base ; 

 but the fact that even in markedly acid proteid 

 solution urea exerts a specific effect upon pro- 

 teids makes this explanation improbable. The 

 numerous definite crystalline compounds formed 

 by the union of urea and mineral salts suggest 

 that it may act by combining with the natural 

 salts of a proteid and so give us an ash-free 

 proteid. Electrolytes exert an influence an- 

 tagonistic to some of the effects of urea upon 

 proteids. The effects of urea upon proteid may 

 be described as: 1. Those of a substance sensibilis- 

 atrice, rendering the proteid more prone to zymo- 

 lysis, conversion into acid or alkali albumin. 2. 

 Protective, since coagulable proteids are not heat- 

 coagulable in its presence, but reacquire their 

 coagulability when the urea is removed by dialy- 

 sis. 3. Solvent. 



Continuing the account of his investigations at 

 the meeting of the British Medical Association, 

 Dr. Ramsden said that a dead frog placed in satu- 

 rated urea solution soon became transparent 

 and shortly fell to pieces. The myeline sheath 

 of nerve was rapidly altered and presented sim- 

 ilar appearances to that of degeneration. Urea 

 converted native egg-white into a jelly. The 

 author at first supposed that urea in these reac- 

 tions was active as a base, but further experi- 

 ments negatived this view for example, urea 

 was equally active on proteid in acid solution. 

 Dr. Ramsden considered that it might act by ren- 

 dering the proteid more sensitive to the action 

 of any acid or alkali present. He had prepared 

 crystalline compounds of urea with proteids and 

 palmitic acid. 



An inquiry by Messrs. Atwater and Benedict 

 into the nutritive value of alcohol, reported in the 

 proceedings of the National Academy of Sciences, 

 concerned the value of alcohol as a fuel in the 

 human body, and a comparison of it as to this 

 point with sugar, starch, fats, and other nutri- 

 tive matters in ordinary foods ; and also the effect 

 of alcohol upon the proportion of nutritive sub- 

 stance digested from food with which it was 

 taken. More than 98 per cent, of the alcohol 

 taken by the subjects was found to be oxidized 

 in the body, and its potential energy to be con- 

 verted into kinetic energy as completely as that 

 of ordinary nutritive matters. Alcohol seemed to 

 be effective in protecting the body fat from con- 

 sumption, but less so in the protection of body pro- 

 tein. A slight advantage was found by the au- 

 thors in favor of the non-alcoholic diet as regards 

 the utilization of the total energy of the food, es- 

 pecially in cases involving hard muscular exer- 

 tion, but the difference was very small, and did 

 not exceed the possible limits of experimental 

 error. 



Dr. Arthur Clopatt, of Helsingfors, has report- 

 ed to the Congress of Finland Physicians concern- 

 ing a series of experiments he has made on the 



effects of alcohol upon the weight of the body. 

 His conclusions were: 1, That alcohol, when the 

 system has become accustomed to it, supplies the 

 place of both nitrogenous and non-nitrogenous 

 food by rendering a smaller amount necessary; 

 and 2, that it has no demonstrable action in pro- 

 moting the absorption of food from the intestine. 

 The author in his paper cites the older authorities 

 on the subject, such as Tiedemann, Gmelin, and 

 Lallemand, as having believed that alcohol was 

 excreted unburned from the economy; and the 

 later experiments, including those of Anstie, Binz, 

 and Strassmann, as having shown that it is to a 

 certain extent destroyed in the body by oxidation. 



From the researches of Drs. Osborn and Zobel, 

 as communicated to the British Association, it 

 appears that glycogen when hydrolyzed by a dia- 

 stase ferment gives rise to bodies very similar to 

 those derived from starch. Among these is the 

 body called isomaltose, which was shown by 

 Brown and Morris to be a mixture of maltose and 

 a dextrin-like body. When acted upon by saliva 

 glycogen gave dextrin, dextrose, and maltose. 



The experiments of E. Weymouth Reid on the 

 intestinal absorption of solutions go to show that 

 a physical explanation of absorption is not ad- 

 missible. 



Glands and Secretions. A crystalline body 

 of constant composition has been obtained from 

 the suprarenal gland by Jokishi Takamine, who, 

 on account of its extremely potent action as a 

 vasomotor constrictor, was led to believe it the 

 active principle of the gland, and named it ad- 

 renalin. It is a white, light, microcrystallized 

 body; assumes fine forms; has a slightly bitter 

 taste; is sparingly soluble in its dry form; has a 

 faintly alkaline reaction; and combines with va- 

 rious acids to form salts. It is a powerful redu- 

 cing agent in alkaline and neutral solutions, and 

 absorbs oxygen from the air. It may be used as 

 a photographic developer. The author observes 

 that the isolation of the active principle of the 

 gland seems to point toward the fact that the 

 Avonderful physiological actions of the various 

 glands may depend upon the effects of apparently 

 simple chemical substances. Such isolation would 

 naturally give an impetus to the search for active 

 principles of the various organs concerning which 

 we know but little. 



Experiments illustrating the importance of the 

 adrenal glands to life are described by Dr. Hans 

 Stehl and Dr. Otto Weiss in Pfliiger's Archiv. 

 The investigations of Tolstoi and Nothnagel, 

 who thought these glands were not essential, were 

 regarded as liable to criticism, because the au- 

 thors had not made sure of the absence of acces- 

 sory adrenals. The authors found structures of 

 this kind in rabbits. Operations of total exter- 

 mination were performed on dogs, cats, mice, 

 a hedgehog, a weasel, and frogs. Experiments 

 made on animals from which only one adrenal v> ;is 

 removed were uniformly fatal in guinea-pigs, but 

 other animals did not seem to suffer much incon- 

 venience. In animals that died after both glands 

 had been removed, the symptoms were' great mus- 

 cular weakness and apathy; the gait was vacil- 

 lating, the legs were strangled, and the head was 

 depressed, the temperature fell slowly, the blood- 

 pressure was diminished, and where both adre- 

 nals were removed, it fell till the death of the ani- 

 mal. Transplantation of the adrenals, even into 

 parta that were highly vascular, was never suc- 

 cessful. It was difficult to determine certainly 

 the cause of death. Some attributed it to loss 

 of nervous power; others to the failure of supply 

 of a substance secreted or produced by the adre- 

 nals which, entering the blood, keeps up the blood- 



