PHYSIOLOGY. 



559 



rubin, biliverdin, urobilin, and proteinchrom that 

 the characteristic bands in the violet part are 

 absent. But from this observation it must not 

 necessarily be inferred that these organic pig- 

 ments are not derivatives of hemoglobin, for, as 

 the investigators named point out, the charac- 

 teristic absorption bands in the violet area of the 

 spectrum produced by the complex molecule of 

 hemoglobin may not depend on the constitution 

 of the nucleus forming the basis of this completed 

 mother substance, but may arise from certain 

 atomic groups which do not appear in some of 

 the dervatives. 



In a paper read before the British Medical As- 

 sociation on the Action of Certain Hemolytic 

 Agents on Nucleated Blood-Corpuscles, Prof. 

 Stewart observed that mammalian red blood-cor- 

 puscles presented certain properties which at 

 first sight appeared to be vital phenomena, and 

 yet were certainly of physical origin; for exam- 

 ple, selective absorption. Thus ammonium chlo- 

 rid was taken up by the corpuscles, while sodium 

 chlorid was not; and this happened in formalde- 

 hyde-hardened corpuscles as well as in living 

 ones. In this research, the author had shown 

 that similar phenomena were found in the nucle- 

 ated corpuscles of amphibia, birds, fetal mam- 

 mals, and the corpuscles of bone-marrow. Of 

 special interest were the observations on the cor- 

 puscles of Necturus, a tailed amphibian with very 

 large corpuscles. 



Experiments are described by Swale Vincent 

 and William Sheen which go to show that nerv- 

 ous, muscular, glandular, and other animal-tissue 

 extracts produce a fall of blood pressure when 

 injected into the circulation. Whether or not the 

 depressor substance or substances are identical in 

 the different extracts, the authors are not pre- 

 pared to say. 



Appearances in liver which had been injected 

 with acid carmine gelatin from the portal vein 

 are described by E. A. Schafer as seeming to 

 offer objective proof of the conclusion of Bro- 

 wicz that a network of nutritive canals exists 

 within the hepatic cells, which are in direct com- 

 munication with the lobular blood capillaries. 

 Browicz had not been able to verify his conclu- 

 sion by injection, as Schafer believes has been 

 done in this case. 



A method of estimating the oxygen and car- 

 bonic acid in small quantities of blood and the 

 apparatus through which it is applied are de- 

 scribed by Joseph Barcroft and J. S. Haldane 

 in the Journal of Physiology, vol. xxviii, No. 3. 



From investigations of the local reaction of 

 the arterial wall to changes of internal pressure, 

 W. M. Bayliss demonstrates that the muscular 

 coat of the arteries reacts, like smooth muscle 

 elsewhere, to a stretching force by contraction, 

 and to a diminution of tension by relaxation. 

 These reactions are of myogenic nature, are inde- 

 pendent of the nervous system, and can be ob- 

 served not only in the living state, but in expired 

 arteries several hours after death. 



Digestion. Prof. W. C. Halliburton, in his 

 address to the section of physiology of the Brit- 

 ish Association, cited, in illustration of the value 

 of bold experimentation, the work of Pawlow, 

 who had, by the introduction of new and bold 

 methods of experiment, thrown a new light upon 

 the processes of digestion. He had shown that 

 digestion is not a succession of isolated acts, but 

 each act is related to its predecessor and to the 

 act that follows it. The process of digestion is 

 thus a continuous whole; for example, the acid- 

 ity of the gastric juice provides for a delivery of 

 pancreatic juice in proper quantity into the intes- 



tine; the intestinal juice acts upon the pancreatic, 

 and so enables the latter to perform its powerful 

 actions. Further, the composition of the various 

 juices is admirably adjusted to the needs of the 

 organism; when there is much proteid to be di- 

 gested, the proteolytic acidity of the juices se- 

 creted is correspondingly high, and the same is 

 true for the other constituents of the food. 



In experiments on the nerve movements and 

 innervation of the stomach, Dr. Page May found 

 that a short time after the taking of food by the 

 animal movements of a rhythmic character arose 

 in the wall of the organ. These movements were 

 waves of contraction, each of which began near 

 the esophageal end of the stomach. The waves 

 succeeded each other at the rate of about three 

 per minute, and slowly increased in strength as 

 they passed toward the pylorus. The contractions 

 originated in the wall of the organ itself; for they 

 continued for half an hour or more after removal 

 of the viscus from the body and its preservation 

 in a bath of warm saline solution. The small 

 ganglia in the wall of the stomach probably co- 

 ordinated the contractions. Although the gastric 

 contractions were of autochthonous origin, they 

 were subject to the control of the central nerv- 

 ous system by means of the vagus nerve, espe- 

 cially of the left vagus nerve. On stimulating the 

 peripheral end of the vagus nerve, the tone of 

 the gastric muscle was usually at once much 

 diminished. Any gastric contractions were then 

 usually abolished. Shortly after this, on the 

 contrary, renewed movements set in, often very 

 vigorous in character, and usually about four 

 times as powerful as the contractions during 

 ordinary digestion activity. Thus the first effect 

 of stimulation of the vagus was inhibition of the 

 gastric tone, the second increase of tone and 

 augmentation of movement. Substitution of the 

 central end of the vagus produced a slight inhib- 

 itory effect upon the stomach if the other vagus 

 nerve was intact. The splanchnic nerve was not 

 found to exert any influence upon the muscula- 

 ture of the stomach, either in the direction of 

 augmentation or of inhibition. Occasionally 

 some inhibition of gastric movement was excited 

 by the stimulation of the splanchnic. Anemia of 

 the stomach experimentally produced by block- 

 ing the thoracic aorta cut short the normal con- 

 tractions of that organ. The cerebral centers for 

 the gastric movements and tone, which have been 

 described by many observers, notably by Bech- 

 terew and Opendousky, were not found, although 

 diligently searched for. No definite effect upon 

 the movement of the stomach seemed to result 

 from any central stimulation. 



The researches of W. Ramsden indicate that 

 urea has a potent influence upon proteids. Its 

 presence up to saturation prevents the coagula- 

 tion by heat of all proteid solutions examined. 

 Globulin, caseinogen, acid and alkali albumin, 

 copper albuminate fibrin, and even heat-coagu- 

 lated proteids swell up and dissolve in a satu- 

 rated aqueous solution of pure urea. Dry gelatin 

 is dissolved at room temperature until 40 per 

 cent, is in solution. If the urea is removed by 

 dialysis the gelatin sets solid again. Coagulable 

 proteids are converted at room temperature into 

 a substance possessing all the properties of acid 

 or alkali albumin according as the reaction of 

 the original proteid solution was alkaline or acid. 

 The presence of urea enormously accelerates the 

 conversion of proteids into either acid or alkali 

 albumin, and even causes such conversions when 

 none would take place in its absence. Similarly 

 urea facilitates the conversion of hemoglobin 

 into alkaline hematin or acid hematin. The 



