646 



PHYSIOLOGY. 



ularity of the ventricles results in consequence 

 of the sinus and idio-ventricular rhythms inter- 

 fering with one another. The authors prefer 

 the term augmentor nerves to that of acceler- 

 ating nerves. Excitation of these nerves in the 

 dog leads more often to augmentation in the 

 force than in the frequence of contraction. The 

 two effects do not go hand in hand. Vagus ex- 

 citation relieves the heart of work, and there- 

 fore of waste, to as great an extent as is compati- 

 ble with a continuance of the circulation ; the 

 vagus may therefore be looked upon as pri- 

 marily the protective nerve of the heart ; sec- 

 ondarily, it acts in the interests of the central 

 nervous system ; while the presence in the sci- 

 atic and other mixed nerves of fibers which 

 cause reflex vagus excitation seems to indicate 

 that the nerve may be used by other parts of the 

 body to diminish the output of the heart, and so 

 to reduce the activity of the circulation as a 

 whole. The idio-ventricular mechanism must 

 be looked upon as a means whereby arrest of the 

 circulation and death is prevented when the 

 vagus action exceeds a certain limit. The aug- 

 mentor nerves, on the other hand, increase the 

 work and tissue of the heart, and this organ is 

 sacrificed for the needs of the economy until 

 the vagus is called into play by cardiac reflex. 

 The output is increased, and the ventricles are 

 enabled to pump out their contents against 

 heightened arterial blood pressure. Other con- 

 siderations dealt with by the authors are the 

 mode of interaction of the vagi and augmentors, 

 and factors other than nervous affecting the 

 heart's contractions. 



The cause of a difference in the radial pulse of 

 the two sides in certain heart affections has been 

 studied by Prof. L. V. Popoff. The phenomenon 

 is frequently observed with mitral stenosis, asso- 

 ciated with mitral incompetence, especially where 

 there is considerable disturbance of the compen- 

 sation, the pulse being small and irregular, and 

 the dilatation of the heart, and especially of the 

 left ventricle, very marked. Under these condi- 

 tions the pulse in the left radial artery is found 

 to be decidedly weaker than that in the right 

 sometimes, indeed, the latter may be easily 

 counted, while the former is hardly perceptible. 

 Sometimes the pulse is so small and weak that it 

 will not give a sphygmographic tracing, and the 

 difference can be detected only by the feel. As 

 the heart's action improves the difference grad- 

 ually becomes less and less marked. The author 

 says, in explanation of this, that he found in the 

 cases described a pressure of the enlarged auricle 

 and its appendix, and even of enlarged pulmo- 

 nary vessels, against the arch of the aorta, and 

 especially against the part from which the left 

 subclavian arises. Of course, if the heart's action 

 is feeble, such a pressure must diminish the cir- 

 culation through the left arm in comparison 

 with that through the right; but if the aorta is 

 well filled out, this pressure may have but little 

 effect. Again, probably the greater length of 

 the arterial course on the left side, and the more 

 acute angle which the left subclavian makes with 

 the arch of the aorta, as compared with that 

 made, by the right subclavian with the innomi- 

 nate, 'must be borne in mind, as it probably has 

 some influence on the question. The differential 

 pulse is more frequently observed in young or 



middle-aged subjects than in elderly people, as 

 in the latter the heart, owing to the loss of elas- 

 ticity and consequent elongation of the great 

 vessels, lies lower, and therefore farther away 

 from the arch of the aorta. 



The properties possessed by the serum of blood 

 of killing disease germs and of dissolving and 

 destroying the red blood-corpuscles of other ani- 

 mals, have been studied by Herr Buchner. These 

 powers are gradually lost when the liquid has 

 been removed from the animal, and are destroyed 

 by heating half an hour to from 52 to 55 C. 

 Light also stops both actions, and diffuse day- 

 light more than direct sunlight. It is apparently 

 albumens in the serum that are operative ; but 

 whether all the albuminoid constituents, or 

 certain specific albumens, was not determined. 

 It is remarkable that solution of the serum with 

 a 0'7-per-cent solution of common salt does not 

 spoil the action, whereas a similar dilution with 

 pure water makes the serum nearly inactive. But 

 serum made inactive with water recovers its prop- 

 erties if salt solution is added, and this is the case 

 even when the serum has been kept in the active 

 state for from four to twenty-four hours in ice. 

 Serum may also receive a 0'7-per-cent. solution 

 of potassium or lithium chloride, or various 

 other salts of the fixed alkalies, without losing 

 its germicide properties. Ammonium salts even 

 stimulate these. Herr Buchner calls the albu- 

 mens in question alexines (or protective mat- 

 ters) ; he supposes they have a like action on for- 

 eign cells generally. The serum of dogs and 

 rabbits having been mixed, the power of both 

 alexines was weakened, but those of the rabbit 

 more than those of the dog (for typhus bacilli). 

 After acting some time on each other the globu- 

 licide power was extinguished. The author finds 

 in these facts an explanation of the antitoxical 

 action of the serum of animals protected against 

 disease. 



Having studied by the aid of original prepara- 

 tions the origin of haemoglobin of the fusiform 

 corpuscles and of the haamatoblasts in the blood 

 of amphibia, Dr. A. B. Macallum concludes that 

 the haeinatoglobin of the blood corpuscles is de- 

 rived from the abundant nuclear chromatin of 

 the haematoblasts. This chromatin, he consid- 

 ers, is an iron compound, the constant oxidation 

 and reduction of which constitutes the chemical 

 process underlying life. The fusiform cells of 

 amphibian blood, he maintains, are derived from 

 the blood corpuscles are, in fact, the remains of 

 the broken-up or destroyed red cells, the latter 

 in this conversion losing the cell membrane and 

 the greater portion of the discoplasma. The 

 haamatoblasts in arnblystoma are probably the 

 direct descendants of cells split off from the ex- 

 treme ventral portions of the visceral mesoblast. 

 An interesting contribution to our knowledge of 

 the adaptation of structure to function in the 

 human body is afforded by the investigation by 

 Signor Minervini, of Naples, of the blood vessels 

 of the skin in different parts. Portions of skin 

 were prepared so as to show the exact structure 

 of the chief arteries in them. The results are as 

 follow : 1. The artery walls of the skin in men 

 are generally thicker'than those of other organs ; 

 2. This greater thickness is due generally, and 

 during most of life, to the. thickening of the 

 middle layer ; but in childhood the outer, and in 



