648 



PHYSIOLOGY. 



Speaking in the Berlin Physiological Society on 

 the regeneration of the blood corpuscles in man, 

 and on the structure of the organs therein con- 

 cerned, as based on serial sections through lym- 

 phatic nodules, the spleen, and the marrow of bones, 

 Dr. Benda said that he had come to the conclusion 

 that in the nodules the germinal center, the germi- 

 nal layer, and the more peripherally placed leucocytes 

 form part of a developmental series. He had found 

 similar structures in the spleen and in the red cor- 

 puscles of the marrow bones. 



With an apparatus for registering the changes of 

 volume of the hand and wrist during the period of 

 normal sleep, Prof. W. H. Howell has found that a 

 gradual increase in volume takes place from the be- 

 ginning of the attempt to go to sleep, the uncon- 

 sciousness of sleep appearing at some time during 

 the increase. The volume reached its maximum 

 within one or two hours after the beginning of 

 sleep, and then remained for an hour or two prac- 

 tically constant. Following upon this appeared a 

 gradual constriction, which at first was moderate, 

 but increased more rapidly during the first half or 

 three quarters of an hour of sleep, and brought the 

 volume curve at the time of awakening nearly or 

 quite to the point shown at the beginning of sleep. 

 The curves throughout the sleeping period exhibit- 

 ed also long periodic waves of constriction and ex- 

 pansion, lasting for an hour or more, and numerous 

 shorter rapid constrictions and expansions, which 

 were connected with the movements of the sleeping 

 subject or with external stimuli, such as noises in 

 the street. Upon the assumption that the increased 

 volume was owing to a vascular dilatation, particu- 

 larly in the skin, the author points out that, upon 

 the accepted view of the regulation of blood supply 

 in the brain, the volume of the circulation and 

 the pressure within this organ during sleep must 

 stand in reciprocal relations to the volume changes 

 exhibited by the limbs that is, during the period 

 of sleep the blood supply to the brain and the intra- 

 cerebral pressure gradually diminish to a minimum, 

 which is reached within the first one or two hours; 

 this condition remains practically constant for the 

 following hour or two, and is then succeeded by a 

 gradual increase in blood flow and intracerebral 

 pressure, which may be said to reach the normal 

 condition at the time of awakening. The vascular 

 changes are explained by a fatigue and subsequent 

 resumption of tone in the vasomotor center, espe- 

 cially in that part controlling the skin circulation. 



Haldane and J. L. Smith find that the oxygen 

 tension of arterial blood is about 26'2 per cent, of 

 an atmosphere, or 200 millimetres of mercury, and 

 that the process of diffusion alone does not explain 

 the passage of oxygen from the air of the pulmo- 

 nary alveoli to the blood. 



In his studies of the mammalian heart, W. T. 

 Porter found that a fall in the volume of the coro- 

 nary circulation of 73 per cent., for example 

 caused a fall in the force of the heart of 49 per 

 cent., while the frequency of the beat was altered 

 only 9 per cent. Restoring the volume of the coro- 

 nary circulation restored the frequency of the heart 

 beat. The change in force followed the change in 

 blood supply immediately. 



Miss Plyde reports to the American Physiological 

 Society that she has found that distention of the 

 left ventricle diminishes per se the volume of the 

 coronary circulation. It acts further as a stimulus 

 to the cardiac muscle, causing the ventricle to beat 

 more strongly. Strong contractions of the ventricle 

 cause an increase in the volume of the coronary cir- 

 culation. If the ventricle, having been distended, 

 is placed again at atmospheric pressure, the force of 

 contraction is much diminished. 



W. T. Porter finds that stimulation of the pe- 



ripheral end of the vagus nerve occasions diminu- 

 tion in coronary flow. Increase in coronary circula- 

 tion follows stimulation of the cervical sympathetic. 

 These results are held to indicate vasoconstrictor 

 fibers in the vagus and vasodilator fibers in the 

 sympathetic. 



The nuclein-therapy theory of leucocytosis and 

 immunity is criticised" by Dr. W. A. Wells", of Wash- 

 ington, who summarizes his conclusions on the sub- 

 ject by predicating that, notwithstanding the long- 

 continued conflict as to the importance of the cell 

 and of the lymph, respectively, as the protecting 

 agency of the body, it is probable that the claims 

 on each side will be found reconcilable ; that there 

 is no reason for regarding the leucocytosis which 

 appears after the introduction of nuclein into the 

 system as produced differently from that which fol- 

 lows from a great number of other agents, many 

 of which are poisons ; and that the most rational 

 explanation of leucocytosis is according to the 

 principle of chcmotaxis. The predominance of 

 polynuclear cells is therefore accounted for in the 

 greater sensitiveness of these forms to chemotactic 

 influences. We must regard, therefore, a leucocy- 

 tosis as only a local condition that is, only a de- 

 termination of the white cells into the peripheral 

 circulation, without any real, significant, absolute 

 increase of the whole number of these cells. The 

 leucocytosis produced by nuclein is of this kind. 

 The uric acid found in increased amount in the 

 urine after administration of nuclein may be formed 

 from the nuclein direct and not from the white 

 blood corpuscles. There is, moreover, no constant 

 correspondence in the number of leucocytes and 

 the amount of uric acid excreted, for there may be 

 often an increase of uric acid without leucocytosis. 

 There is some reason for believing that, of all leuco- 

 cytes, those possessed of the eosiniphilic granules 

 perforin the most essential part in protecting the 

 organism against infectious diseases. A suggestive 

 correspondence exists between those diseases which 

 are distinguished by an augmentation of eosini- 

 philes and diseases antagonistic to tuberculosis. 



A paper read in the British Association by Dr. 

 Durham showed that a gradual, though rapid, dis- 

 appearance of certain leucocytes from the peritoneal 

 cavity takes place, due first to their aggregation, 

 and secondly to their adhesion to the omentum. 

 Another factor is the rapid passage of the cells 

 along the lymphatics, and this is a strong argument 

 against too rigid a theory of ccelomic and haemal 

 white corpuscles. There would appear to be a 

 definite peritoneal circulation of cells and fluid 

 from the mesenteric blood vessels to the mediasti- 

 nal lymph vessels almost from the moment after 

 intraperitoneal injection until the normal condition 

 has been re-established. 



Digestion. Since the discovery by Bernard, in 

 1835, that the liver, in its sugar-producing function, 

 is connected with the. general metabolism of the 

 body, confirmed as it has been by subsequent re- 

 searches, the view that it is simply a bile-forming 

 gland has steadily lost ground. The liver is on the 

 direct channel of absorption of carbohydrates and 

 proteids, but it is not on the route of the absorption 

 of fats, which, according to Munk. are all absorbed 

 by the lymphatics, and reach the liver only through 

 the hepatic artery. Yet a connection with the 

 metabolism of fats is suggested by the enormous 

 accumulation of fats in some animals at certain 

 seasons, and under conditions not pathological. 

 The question whether this is so has been investi- 

 gated by D. Noel Paton, who after two years of 

 patient analyses has found that a uniform distri- 

 bution of the substances soluble in ether, called 

 fats, exists throughout the various parts of the 

 liver ; that the ether extract, while it varies greatly 



