180 Report of the Che:micvl Department of the 



than under either of the other two conditions. From this it 

 mi?;ht be inferred that 15 per ct. of ether was more favorable to 

 enzyme action than 3 per ct. chloroform, but the results of the 

 bacteriological analyses give some reason for believing that 

 there had taken place a growth of bacteria. There had probably 

 been a corresponding increase in the amount of bacterial enzyme. 

 This is rendered more likely by the fact that the bacteria in this 

 case were almost entirely of a single kind, which showed ability 

 to grow in the presence of ether, formed spores quickly in almost 

 every cell and elaborated enzyme with great freedom. 



This experience has made us slow to accept as trustworthy 

 any results obtained with the use of ether, when the conditions 

 are not constantly controlled by quantitative examination of the 

 bacterial content. 



OOMPARISON OF EFFECTS OF CHLOROFORM AND FORMALIN UPON 



ACTIVITY OF ENZYMES. 



Jensen^'^ in a suggestive article on the enzymes of cheese ripen- 

 ing has called attention to the use of 0.1 per ct. of formalin in 

 studying their activity. Babcock and RusselP^ have stated that 

 comparatively small amounts of this substance completely 

 inhibit enzyme activity. The use of even the amounts recom- 

 mended by Jensen is to be looked upon with suspicion until the 

 influence of formalin upon enzyme action is more fully 

 investigated. 



In order to facilitate comparisons at some future time, we give 

 the results of parallel examinations of four samples of milk con- 

 taining respectively 4 per ct. of chloroform and 0.1 per ct. of 

 formalin by volume. Unfortunately the strength of formalin 

 was not redetermined but it was the 40 per ct. article of 

 commerce. 



The milk in this case was obtained from the four quarters of a 

 single cow at one milking. The flank and udder were brushed 

 and moistened. The hands of the milker were smeared with 

 vaselin and the milk was caught in four-inch glass funnels lead- 



"Jeiisen. See No. 9. 



"Babcock aud Russell. Add. Kept. Wis. Exp. Sla. 15:77 (189S). 



