156 



PROCEEDINGS OF THE AMERICAN ACADEMY 



The limits of variation as observed by some of the above observers 

 were as follows : — 



It should be remarked, in this conuection, that Dr. Voelcker's results 

 should be received with a good deal of caution, since he acknowledges 

 the cows were half starved ; and, further, he refuses to give the methods 

 employed in his analyses. Von Baumbauer, on the other hand, has 

 given the fullest information in regard to the methods he employed, 

 the feed of the cows, time milking, &c. 



The benzine used was the ordinary commercial article distilled from 

 Pennsylvania petroleum of a specific gravity of about 70° B. Gaso- 

 line of the specific gravity of 90° B. w'as at first used ; but it was found 

 on trial that the heavier article was just as efficient in removing the 

 fat, and that it left no residue on evaporation, while it was much safer 

 to have in the laboratory. 



