714 



PHYSIOLOGY. 



a bearing on the general pathology of inflamma- 

 tion. Attention is especially drawn to the fact 

 that the inflammatory condition of the lungs is 

 in a sense directly continuous with the normal 

 process of respiration. The transition from the 

 physiological to the pathological stage is imper- 

 ceptible. Oxygen, which at the tension of the 

 atmosphere stimulates the lung cells to active ab- 

 sorption, at a higher tension acts as an irritant 

 or pathological stimulant, and produces inflam- 

 mation. 



It was pointed out by Dr. A. Foxwell, in the 

 Bradshaw Lecture to the College of Physicians, 

 London, that the first result of exercise is an in- 

 crease in the rise and depth of the inspirations 

 that is; of respiratory exchange. The respiratory 



CO 

 quotient 2 is not increased, but rather, if 



U 2 



.anything, diminished; in other words, the tissues 

 are as j'ich (or richer) in oxygen as during rest. 

 This necessitates a great increase in the absorp- 

 tion of oxygen at the time ; for it has been shown 

 that a man gives off ten times as much carbonic 

 acid when on the treadmill as he does when 

 asleep. The fact is noted that arm work, per 

 unit of work done, requires a greater absorption 

 'of oxygen than climbing, and climbing than walk- 

 ing on the level. If the amount of oxygen ab- 

 sorbed during sleep per minute be 100 grammes, 

 then in a minute's walking at three miles an hour 

 on the level it would be 500 grammes, in climbing 

 a yard high 5,000 grammes, and in doing the same 

 number of kilogrammetres by turning a wheel 

 (arm work) 7,000 grammes. As to the distribu- 

 tion of the serious strain imposed upon the organs 

 by the enormous increase in the absorption of 

 oxygen and the giving out of carbonic acid, Dr. 

 Foxwell considers that the lungs and the right 

 ventricle of the heart bear the brunt of the extra 

 labor involved in short, strenuous exertions. 



Cheyne-Stokes breathing as defined by Stokes 

 consists in the occurrence of a series of inspira- 

 tions increasing to a maximum and then declin- 

 ing in force and length, each inspiration being 

 less deep than the preceding one until they are 

 all but imperceptible, and then a state of a'ppar- 

 ent apnoea occurs. This is at last broken by the 

 faintest possible inspiration, followed by one more 

 decided, marking the commencement of a new 

 ascending and then descending series of respira- 

 tions. In some cases the sequence of events is 

 not so perfectly regular. The ocular phenomena 

 which occur in association with Cheyne-Stokes 

 breathing are regarded by Arthur L. Whitehead 

 as worthy of attention not only as clinical 

 facts, but because they may possibly help to 

 throw light upon the aetiology of the symp- 

 tom. In the majority of recorded cases no 

 eye symptoms have been observed, but in some 

 -others definite disturbances of the intra- and ex- 

 tra-ocular muscles have been remarked. From 

 the consideration of a number of cases cited from 

 the records of many observers, Mr. Whitehead 

 finds it evident that the ocular symptoms in ques- 

 tion are of considerable variety, and may be ob- 

 served in what may conveniently be called a 

 Cheyne-Stokes state or condition apart from anv 

 disturbance in the rhythm of respiration. Every 

 variety of case may be seen, from simple Chevne- 

 btokes respiration to the complete clinical picture 

 of the phenomenon accompanied during the pause 

 by unconsciousness, closed eyelids, contracted 

 pupils, and lateral conjugate deviation of the eye- 

 balls, while the pulse is frequent, small, and of 

 moderately high tension. At the end of some sec- 

 onds consciousness returns, the eyes open, the pu- 

 pils slightly dilate, the pulse loses some of its ten- 



sion, and a superficial respiration follows. Cases 

 of an intermediate character are referred to, and 

 some that show that the periodic changes pro- 

 duced by alternations in the centers may begin 

 in and be limited to those which are not con- 

 cerned in vital phenomena. 



In experiments made with sodium peroxide for 

 absorbing from the air of a closed chamber car- 

 bonic acid, water vapor, and other irrespirable 

 gases produced by a living animal within the 

 chamber, and at the same time keeping up the 

 supply of oxygen, MM. Desgrez and Kaltha/.ard 

 found that while guinea pigs died very soon when 

 no corrective provision was made, when sodium 

 peroxide was placed in the chamber and water 

 was allowed to drop upon it the animals lived a 

 considerable period with no perceptible diniinu- 

 .tion of vitality. The reaction in the experiment 

 was Na 2 O 2 + H I O = 2N'OH + O. M. D'Arson- 

 val proposes as an effective method of achicxing 

 the same end of the preservation of life the pro- 

 vision in the upper part of a tubulated receiver, in 

 which the animal is inclosed hermetically, of a 

 receptacle filled with pieces of soda lime; through 

 the tubulua a solution of hydrogen peroxide com- 

 ing from a Mariotte's bottle, is conducted by a 

 tube so as to drop into a strong solution of 

 chromic acid. The apparatus works automat- 

 ically, for as the animal breathes and the OH Hum 

 dioxide and water are absorbed by the soda lime 

 the pressure falls and the Mariotte's bottle comes 

 into action. The hydrogen-peroxide solution then 

 begins to drop into the chromic acid, and dis- 

 engages oxygen until the pressure is restored. 

 The flow from Mariotte's bottle then stops, and 

 the cycle begins again. 



Experiments described by Vaughn n Harley 

 seem to show that when one pleural space is filled 

 up so that the lung on one side is complex l and 

 ojily the opposite lung remains active, a marked 

 increase in the rate of breathing follows the ma- 

 jority of cases. At the same time more air is 

 breathed per minute by the active lung than was 

 previously breathed by the two lungs together. 

 This increase in the quantity of air breathed i* 

 accompanied by an increase in the quantity of 

 oxygen absorbed and of carbonic acid eliminated 

 by the animal, the two being increased par I pnssu 

 so that the respiratory quotient as a rule is not 

 altered. The explanation of this increase is a sub- 

 ject for further investigation. 



A new respiration calorimeter, devised by Prof. 

 W. O. Atwater and E. B. Rosa, is intended for use 

 in inquiries bearing first on the question as to 

 whether the principle of conservation of energy ] 

 holds good in the living apparatus, and, second, 

 assuming this law to be true, on the acquisition 

 of more definite knowledge of the ways in which 

 the body is enriched and of the values and uses 

 of food. 



Circulation. Several varieties of the condi- 

 tion of insufficiency of heart muscle are described 

 by Martius. The first is pure acute insufficiency 

 resulting from overwork or excessive c\< 

 The results of acute strains on a henlthy heart 

 are soon recoyered from under the influent 

 rest, but often repeated strains lead to weakness. 

 The second variety, acute myocardial insuffi- 

 ciency, is the primary and essential cause of par- 

 oxysmal tachycardia. The enormously increased 

 frequency of the pulse is secondary.' With re- 

 covery a return of efficiency ensues, which is 

 brought on by a rapid disappearance of the dila- 

 tation of the heart. Third, a dilatation of the 

 heart in very weak and anaemic girls has been 

 observed by Henschen as a result of overwork. 

 The condition develops slowly and persists for a 



