194 REPORTS ON INVESTIGATIONS AND PROJECTS. 



The paper concludes with an extensive discussion of the physiological 

 sources of error in the method used, and the mechanics of respiration and 

 circulation as affected by the breathing of high oxygen. The significance of 

 oxygen in therapy is considered, and suggestions for further research com- 

 plete the paper. The results are summarized as follows : 



In experiments with normal individuals lying at complete muscular rest, 

 12 hours after the last meal, and breathing 40 per cent, 60 per cent, and 90 

 per cent oxygen mixtures, the authors find: 



(a) There is no apparent difference between the metabolism as indicated 

 by gaseous exchange (i. e., the carbon-dioxide output, oxygen consumption, 

 and respiratory quotient) and the metabolism when breathing ordinary air. 



(&) There is no change in the respiration, either as to character, depth, or 

 frequency, as compared with the same factors when breathing ordinary air. 



(c) The pulse-rate is lower with oxygen-rich mixtures than when breath- 

 ing ordinary air ; furthermore, the higher the percentage of oxygen breathed 

 (up to 90 per cent) the lower the pulse- rate. 



(5) A respiration apparatus for the determination of the carbon dioxide produced by 



small animals. Francis G. Benedict and John Homans. Amer. Jour. Physiol., 

 28, p. 29. 191 1. 



Many problems in metabolism can only satisfactorily be studied by a meas- 

 urement of the total carbon-dioxide output, oxygen intake, and heat produc- 

 tions. On the other hand, for a preliminary survey of a field of study in 

 metabolism, the carbon-dioxide determinations alone are many times of great 

 value. Since these can be obtained with the expenditure of much less time 

 and money than the determinations of the oxygen consumption and the heat 

 production, it follows that an apparatus in which the carbon dioxide can be 

 determined with relative ease will be of great value in connection with me- 

 tabolism experiments. The closed-chamber type of apparatus in which the 

 carbon dioxide is allowed to accumulate, samples of air withdrawn from 

 time to time, and the increment in the carbon dioxide calculated, was success- 

 fully used in the experiments reported in this paper. The carbon dioxide 

 determinations were readily made by means of the excellent Haldane gas 

 analysis apparatus. 



The importance of registering automatically the body movements of men 

 or animals in metabolism experiments has long been recognized, and this 

 apparatus is provided with a unique feature for obtaining a graphic record of 

 all body movements of the animal. The subject is placed inside of a cage, 

 one end of which rests on a knife-edge, the other end being supported by a 

 stout spring. Any change in the position of the center of gravity of the 

 animal varies the tension upon the spring; by means of a pointer fastened to 

 the end of the cage and connected to a water seal in the cover, a direct 

 graphic record of the movements of the cage is made upon a kymograph. 

 The importance of knowing the muscular movements of the animal and the 

 influence of temperature upon the muscular activity are extensively dis- 

 cussed, two curves being shown. The apparatus was devised primarily for a 

 study of the metabolism after the removal of the hypophysis. 



(6) The increase in metabolism due to the work of typewriting. Thorne M. Carpenter. 



Jour. Biol. Chem., 9, p. 231. 191 1. 



By means of the chair calorimeter, a detailed study was made of the 

 increase in metabolism due to the work of typewriting, which included 8 

 experiments with 5 subjects who were skilled operators upon the typewriter. 

 The results of the study are given in this paper. The total metabolism as 



