638 



PHYSIOLOGY. 



movements, among them some giving a record of 

 the onset and culmination of a fainting fit. Phasic 

 respiration, or " Cheyne-Stokes breathing,'' appears 

 to be common at great heights, and is especially 

 well seen during sleep. In one case the respiratory 

 phases are separated by complete cessation of 

 movement as long as twenty seconds. The respira- 

 tory organs tend to pause at the end of expiration. 

 The diminution of stature which always takes place 

 during the day is augmented by a mountain ascent. 

 The author represents that much more work can be 

 accomplished at an altitude of 14,800 feet than at 

 the sea level, and that there is no increase in the fre- 

 quency of the respiratory movement; indeed, both 

 the frequency and the amplitude may be dimin- 

 ished, or with a frequency exactly like the normal 

 the amplitude may be less. The unexpected state- 

 menfis made that on the summit of Monte Rosa 

 the rate of breathing was not always altered, even 

 by fatiguing muscular work. This seems to be 

 because while on the plains the organism takes in a 

 quantity of oxygen which is more than sufficient 

 for its immediate needs, the breathing is not aug- 

 mented at great heights, since, though less oxygen 

 is actually consumed, it is enough, and more than 

 enough, for the needs of the organism. The ex- 

 periments of Loewy and Leo Zuntz, on the other 

 hand, show that on mountains, when a height of 

 8,900 feet is reached, even at rest there is a slight 

 increase in the gas exchanges and in the rate of 

 breathing, while there is a great increase of both 

 at the height of 14,800 feet. Prof. Mosso believes 

 that mountain sickness is due to an actual diminu- 

 tion in the quantity of carbonic acid in the blood, 

 assuming in his theory of acapnia that this gas is 

 the normal exciting agent for causing a discharge 

 from the nerve cells in the medulla oblongata. 

 Some of Prof. Mosso's conclusions are opposed to 

 views previously held, or differ from those resulting 

 from the experiments of others, and are regarded as 

 subject to criticism or needing further verification. 



It being a fact of common clinical experience 

 that the most varied types of disease involve some 

 damage to the lungs, with consequent increase of 

 the danger to life, the functional variations in the 

 process of oxygen absorption by the lung have 

 been investigated, so far as they are of a physiolog- 

 ical nature, by J. Haldane and J. Lorrain Smith. 

 Studying conditions affecting the organism as a 

 whole, as the state of fever and the accompanying 

 infective process, and conditions in which the im- 

 portant element is some gross change in the lung 

 tissue itself, the authors find that the oxygen ten- 

 sion of the arterial blood leaving the lungs is low- 

 ered to about that of the alveolar air by the general 

 pathological processes that ordinarily occur in fever, 

 and in particular by rise in temperature and by 

 toxic agents of bacterial origin, and that the oxygen 

 tension is also lowered by pathological changes oc- 

 curring in the lungs locally as a result of irritation 

 by high-pressure oxygen. The lowest tension ob- 

 served in the cases where the animal was suffering 

 from some general condition were on the whole 

 higher than the lowest tensionsobscrved when merely 

 local changes in the lungs had been brought about. 

 The observations of oxygen tension showed that in- 

 terference with active absorption through the lung 

 epithelium forms an integral part of many condi- 

 tions of disease directly or indirectly associated with 

 the lungs. The fact that the pathological conditions 

 referred to tend to reduce the oxygen tension of the 

 arterial blood to about that of alveolar air affords 

 striking confirmation, the authors remark, of the 

 conclusion that the absorption of oxygen by the 

 lungs is an active phvsiological process and can not 

 be explained as due s'imply to diffusion. 



M. E. Wertheimer and M. Lepage represented to 



the International Physiological Congress that in 

 experimenting upon the accelerator nerves of the 

 dog they had observed the hitherto unnoted fact 

 that the acceleration, instead of being uniform and 

 constant, as is usually represented, is discontinuous 

 and interrupted occasionally by notable slowings 

 and even intermittence of the pulsations. The phe- 

 nomenon is regarded as simply a manifestation of 

 respiratory irregularities in the heart of the dog, as 

 may be determined by experiment, when the arrests 

 and remissions of the acceleration are found to take 

 place during expiration and the expiratory pause. 

 The alternations may be accounted for when we 

 recollect that the tonic activity of the pnemno-^as- 

 tric diminishes during inspiration and increases 

 anew during expiration. The authors regard the 

 mechanism they describe as a means of protection 

 against overworking of the heart in cases where any- 

 thing tends to produce an excessive augmentation 

 of the frequency of its beating. 



With an instrument called a phonendoscope MM, 

 Regnault and Bianche have studied the modifica- 

 tions impressed upon the thoracic organs by the 

 movements of bicycling. Applying the apparatus to- 

 three champions in a race before the race took place, 

 during its progress, and a few days afterward, they 

 found that the abdominal organs, particularly the 

 spleen, liver, and stomach, were much contracted, 

 the fat under the skin was melted, but the heart 

 and lungs escaped considerable contraction through 

 the flow of blood provoked by the exercise. The 

 continuous movements of the legs and the pelvis, 

 together with the bent attitude, lifted all the abdom- 

 inal organs upward, and these in turn raised the 

 lungs and the heart, especially the right lung, which 

 is so near the liver. The pyloric extremity of the 

 stomach was raised, giving the organ the form of 

 a wallet and causing the food to remain longer 

 within it. In a similar way the heart was pushed 

 up toward the neck. The extent of these evident 

 displacements ranged from two to five centimetres. 



M. P. Lalaine communicated to the Interna- 

 tional Physiologica"! Congress the results of numer- 

 ous experiments which he had made to determine 

 the source of animal heat. His method was that 

 of comparing the heat actually produced by the 

 animal with the heat calculated from the combina- 

 tions effected by the animal while it was sojourn- 

 ing in the calorimeter. The results pointed to the 

 conclusion that, in every case and under whatever 

 conditions, the heat produced by the animal was 

 equal to the heat calculated from the amount of 

 oxygen consumed by it during the same time. 



Circulation. In experiments on heart nutri- 

 tion, reported to the International Physiological 

 Congress, W. T. Porter found an atmosphere of 

 oxygen to be of advantage in maintaining the con- 

 tractions of the mammalian heart. A heart fed 

 simply through the veins of Thebesius and the cor- 

 onary veins will maintain strong rhythmic conl ruc- 

 tions' for many hours if supplied with oxygen at 

 high tension. The same took place when under 

 similar conditions the heart was fed with blo<l 

 serum alone. Further experiments seemed to 

 permit the conclusion that even isolated portions of 

 the mammalian ventricle supplied through their 

 nutrient arteries with a small quantity of serum at 

 very low pressure would maintain rhythmical, long- 

 continued, forceful contractions when surrounded 

 by oxygen at high tension. 



Observations made by Leonard Hill with the Hill- 

 Barnard sphygmometer upon arterial pressure un- 

 der different conditions indicate that a fall of arte- 

 rial pressure is concomitant with bodily rest and 

 quiet mental work just as much as with sleep. < >n 

 rising from bed in the morning and moving about 

 the pressure rises from 10 to 20 milligrammes Hg, as 



