I9I2] 'Alfred P. Lothrop 1S7 



clotted blood was more satisfactory than serum obtained by centri- 

 fuging defibrinated blood. 



The normal surface tension of dog serum (five dogs), from the 

 blood of animals on the usual diet in metabolism experiments in this 

 laboratory, is about 45.5 dynes per centimeter. A daily hemorrhage 

 of 3 per Cent, or more of the body weight, on two successive days, 

 was without material effect on the surface tension. ^^ Small addi- 

 tions of salt to the food raised, whereas additions of sugar lowered, 

 somewhat the surface tension. The Ingestion of extra quantities of 

 meat, several hours before blood was withdrawn, caused a decrease 

 of about 1.5 per cent. in the surface tension. Fasting (1-2 days) 

 raised the surface tension about i per cent. Copious water drink- 

 ing (2 hours before withdrawal of blood) and the administration 

 of magnesium sulfate, with resultant marked diarrhea (a short time 

 prior to removal of blood from another dog), were without appre- 

 ciable effect on the surface tension of the serum. These results 

 suggest that the nutritive State of a given individual must be defi- 

 nitely established before accurate conclusions can be drawn regard- 

 ing the significance of data for surface tension of the subject's 

 blood (or serum). 



[The December issue of the Biochemical Bulletin will pre- 

 sent abstracts of the scientific Communications at the meeting of the 

 Biochemical Association to be held on December 6, at the Columbia 

 Medical School.] 



Biochemical Laboratory of Columbia University, 

 College of Physicians and Surgeons, 

 New York. 



'^When the second bleeding occurred in much less than 24 hours after the 

 first, the surface tension was above normal. 



