NUTRITION LABORATORY. 243 



to provide for the enlarged volume of respiration incidental to severe 

 muscular work. A third spirometer was constructed and loaned 

 temporarily to Geheimrat Professor Dr. L. von Krehl of the I Medical 

 Klinik in Heidelberg; this was copied by Professor Krehl and a similar 

 one was constructed by Professor Otto Cohnheim, of Hamburg. 



MODIFIED RESPIRATION APPARATUS FOR INFANTS AND DOGS. 



While for several years a respiration chamber for use with infants 

 and dogs has been employed in this Laboratory, in which the de- 

 termination of the carbon-dioxide excretion has been satisfactorily 

 made, it was deemed desirable so to modify the apparatus as to 

 permit correct determination of oxygen consumption. During the 

 past year this new form of apparatus was finally developed and at 

 present gives admirable results for both the carbon-dioxide and the 

 oxj'gen determinations, thus permitting many experiments upon the 

 character of katabolism that were impossible with the older form 

 of apparatus. Already several researches with dogs have been 

 carried out with one of these chambers, and during the year almost 

 daily experiments on infants have been made with a second appa- 

 ratus. By means of the combustion of alcohol inside the chamber, 

 the accuracy of the apparatus for making respiratory studies has 

 been amply proved. The registration of minor muscular movements 

 has been further developed, also a method for testing the sensitivity 

 of the apparatus and securing a graphic record. 



In order to compare the relative muscular activity of infants when 

 inside the respiration chamber and when in the ward cribs in the hos- 

 pital during the night, a cradle was constructed, one end of which was 

 suspended by a helical spring, and kymograph records were secured 

 during the night. These records have been of value in interpreting 

 the muscular activity of infants supposedly quietly resting in sleep. 



MISCELLANEOUS EQUIPMENT. 



For a number of years the use of photographic registration appa- 

 ratus in connection with the respiration calorimeters has been care- 

 fully avoided, but the potentialities of this form of record have now 

 been recognized and this device has been adapted to many parts of 

 the apparatus used in connection with the respiration calorimeter; 

 consequently the equipment has been increased by nearly every 

 form of photographic registration thus far devised. An Einthoven 

 string galvanometer, constructed by the Cambridge Scientific Instru- 

 ment Company, with its accompanying optical and photographic 

 registration devices, has been installed in the Laboratory for physio- 

 logical psychology; a Thoma oscillograph, which permits of the 

 photographic registration of four different minute electrical currents 

 of physiological significance, has also been purchased. 



