650 



PHYSIOLOGY. 



quantity. By gastric digestion the colloid is split 

 up into a nonproteid and a proteid substance, of 

 which the former is the active agent in the gland. 

 Notkin, of Kiev, has obtained a substance from the 

 gland which he has named thyro-proteid, and 

 which possesses poisonous qualities, producing, in 

 toxic doses, tetanic symptoms. Dennig finds that 

 the administration of thyroid extract greatly aug- 

 ments for a time the excretion of nitrogen, when a 

 diminished excretion follows ; and an increased ex- 

 cretion of nitrogen under the use of the extract lias 

 also been observed by Bleibtreu and Wendelstadt. 

 Roos has recognized the presence in the gland of 

 an active principle which is of stable composition. 

 Roos's analysis of the thyroid gland and Baumann's 

 of the thymus gland show the constant presence of 

 iodine as a normal constituent of these glands. The 

 quantity present in the thymus varies from 2 o to 

 more than 6 milligrammes in the whole gland. 



In their investigation of conditions influencing 

 the secretion and composition of bile, Dr. Fr. Pl'aff 

 and Mr. A. Balch had the advantage of a patient 

 with a fistula, resulting from an operation, through 

 which all the bile secreted was discharged. The 

 jaundice, which had existed before, disappeared in 

 the course of a few weeks, and the patient felt per- 

 fectly well at the time the investigation was begun. 

 Human bile, ox bile, and the mixture of the pure 

 bile salts, dried and made into pills, increased the 

 daily secretion and the amount of solids. Salol 

 had hardly any effect. Sublimate and calomel, if 

 anything, slightly decreased the daily secretion. 

 During the time of observation ninety-seven days 

 the patient remained perfectly well and gained 

 in weight. 



Experiments made by E. A. Schafer and B. 

 Moore to determine whether the parotid, submax- 

 illary, and sublingual glands possess an internal 

 secretion necessary to the life of the animal or hav- 

 ing any important action on any of the metabolic 

 processes go to show that the salivary glands do 

 not exert any great metabolic influence apart from 

 their external secretion, as does the pancreas. 



In contrast to the statements of Max Xeisser 

 that lymph coining from the thoracic duct does not 

 contain bactericidal properties, S. J. Meltzer and 

 Charles Norris find the lymph coming from that 

 duct in dogs to be distinctly germicidal for the 

 typhoid bacillus. The bactericidal power of the 

 lymph differs from that of the blood in not becom- 

 ing exhausted, even after days. 



Muscular System. The "questions whether the 

 heart muscle can or can not continue working at 

 the expense of its own substance, concerning which 

 former results have been contradictory, and whether 

 an exhausted heart defined as one from whose cap- 

 illary clefts all remnants of blood (or nutrient 

 material) have been washed away have been inves- 

 tigated by Arthur H. White, by methods designed 

 to avoid the faults of the methods of previous stu- 

 dents. The author concludes that " beyond doubt '' 

 the heart is incapable of contracting unless it pos- 

 sesses nutrient material in its capillary clefts. " In 

 the absence of certain salts (the most important of 

 which are sodium carbonate and calcium and potas- 

 sium chlorides) this nutrient material can not be 

 utilized, so that the heart often seems to be ex- 

 hausted long before such is actually the ca?e. In 

 order to enable it to continue working until the 

 last remnant of blood has been washed out of its 

 substance, it is essential that the fluid which is used 

 for perfusion purposes should contain the necessary 

 saline subtances. A stage is finally reached when 

 the heart is so fully exhausted that no stimulus or 

 no amount of feeding with saline fluids will cause 

 it to contract that is to say, it can not contract at 

 the expense of its own substance." When a heart 



is in this fully exhausted condition, it can be re- 

 stored only by feeding it with a true nutrient fluid 

 containing both serum albumin and salts, the for- 

 mer being most essential, while, the latter play a 

 secondary but necessary part in hastening the 

 chemical changes which occur during contraction, 

 as well as neutralizing the effect of such products 

 of metabolism as tend to paralyze the heart's action. 

 Xo fluid can be pronounced nutrient unless it is 

 capable of revitalizing such an exhausted heart. 



The experiments of veterinary Capt. F. Smith 

 upon the maximum muscular effort of the horse 

 were directed toward ascertaining the greatest 

 amount of force the animal is capable of exerting 

 at a given moment, or determining the limit of its 

 power. The method of the experiments was so ar- 

 ranged as, so far as possible, to prevent the pull 

 being a jerk. The 80 horses experimented upon 

 were classified in 4 groups; the highest or " excel- 

 lent " ones being those which met the gradually in- 

 creasing resistance by a gradual increase in force, 

 eventually straining their utmost. Such horses, 

 exerting themselves to the greatest possible extent, 

 were able to reach as an extreme a dead pull of 

 78"5 per cent, of their body weight. The next group 

 in the descending scale " good " could pull 77 - 6 ; 

 the third group, " fair," 70'6 ; and the fourth group, 

 " bad " or " indifferent." C5'6 per cent, of their body 

 weight. The inquiry tells us the greatest force a 

 Imi'sc may exert at a given moment, but does not 

 deal with useful effective force in draught. That 

 is liable to variations according to somewhat com- 

 plicated conditions. 



Investigating the influence of temperature on the 

 working power of unstriated muscle, Dr. Schulz 

 studied the isotonic and isometric contractions of 

 strips from the muscular layer of a frog's stomach 

 in response to maximal electrical stimuli at tem- 

 peratures between 6 C. and + 45 C. From the 

 temperature of the room onward the height of cir- 

 culation increased up to 35, the tension up to 32, 

 while at the same time and up to the same tempera- 

 tures the latent period and duration of the con- 

 tractions diminished. Above these maxima all the 

 phenomena were exactly reversed. At 45 the 

 muscles gave no further reaction, and a tempera- 

 ture of from 60 to 65 caused a permanent short- 

 ening. On cooling below the temperature of the 

 room, both the height of contraction and the 

 tension diminished progressively, whereas the latent 

 period and duration of contraction increased down 

 to a lower limit of 5 to 6 C., at which tempera- 

 ture there was no further reaction. When slowly 

 re warmed contractions again made their appearance. 

 Between 8 and 10 the muscle contracted 

 suddenly and permanently ; but this contraction 

 disappeared on slow warming, the muscle now 

 being inert even at higher temperatures. Compar- 

 ing the striated with the unstriated muscles, Dr. 

 Schulz laid stress on the fact that with a rise of 

 temperature the latter exhibit a gradually increas- 

 ing efficiency up to the maximal, whereas the for- 

 mer, according to Gad and Heymans, show a sec- 

 ondary minimum at 19 C. 



It has been observed by Dr. David Hepburn that 

 the shaft of each metacarpal bone, with the excep- 

 tion of the first, presents 2 triangular areas, a larger 

 in the dorsal aspect and a smaller in the palmar as- 

 pect, neither of which affords origin to muscular 

 fibers. It follows, therefore, that the palmar as- 

 pects of the various metacarpal bones are more 

 fully occupied by muscles than the dorsal aspects. 

 The dorsal interosseous muscles, which are abductor 

 in function, are smaller than current descriptions 

 lead us to believe. This is quite in accordance with 

 the comparatively feeble nature of the abductor 

 movements. Each digit is provided with a short 



