NUTRITION I,ABORATORY. 183 



and leaving the different calorimeters. This apparatus, which has long been 

 planned for, was brought to a successful completion by the assistance of the 

 Leeds & Northrup Company, of Philadelphia, whose extended experience in 

 temperature measurements was of invaluable aid. The apparatus represents 

 perhaps the highest type of recorder for differential temperatures thus far 

 constructed, and the company are to be congratulated on the successful out- 

 come of a very complex problem. 



RESPIRATION APPARATUS. 



Reference has been made in previous reports to the experimental work in 

 progress on a type of respiration apparatus designed for use in hospitals in 

 which the interchange of oxygen and carbon dioxide in the lungs could be 

 studied. The apparatus heretofore most generally used has been that which 

 has rendered such signal service — the apparatus of Zuntz. The great skill 

 required in its manipulation limited its successful use to a very few persons. 

 In the development of the respiration apparatus and calorimeters used in 

 this laboratory, it was believed that a similar type of respiration apparatus, 

 without calorimetric features, could be devised and used with satisfaction 

 and not involve too great technique. This apparatus has been finally brought 

 to successful completion, submitted to the most vigorous tests, and is now in 

 constant use in studying problems of metabolism. It bids fair to be a most 

 valuable adjunct to the respiration calorimeter in studying the many prob- 

 lems which do not warrant the costly calorimetric measurements. 



MINOR APPARATUS. 



The series of experiments on diabetics has called for a polariscope and 

 special room for its use. The instrument is used for studying not only the 

 percentage of sugar present in diabetic urine, but more particularly for 

 studying the y8-oxybutyric acid appearing in grave cases of diabetes. The 

 room has been constructed and a specially accurate polariscope has been 

 purchased. 



In connection with thermometric measurements, an accurate cathetometer 

 for reading mercurial thermometers has been purchased. 



COOPERATING INVESTIGATORS. 



During the past year a number of scientists not regularly attached to the 

 staff of the Nutrition Laboratory have cooperated to a greater or less extent 

 in scientific researches. During the fall of 1908, Dr. W. Falta, of the First 

 Medical Clinic in Vienna, came to this Laboratory by means of a grant fur- 

 nished especially for this purpose by the Vienna Academy of Sciences, to 

 study the respiration apparatus and to make experiments on diabetics. Dr. 

 Falta's brilliant researches in diabetes of animals made his suggestions and 

 cooperation of the greatest value in the successful inauguration of an 

 extended research on diabetes in man. 



