MARKET COLD-STORAGE CHICKENS. 91 



for certain animals, digestion does not proceed better at temperatures 

 much below this. Miiller a compared the action of pepsin from the 

 stomach of the pike at 0° and at 24° C. and found that it took seven 

 times as long to accomplish a given amount of work at the former as 

 at the latter temperature, the pepsin being very active at 24° C. 



Flaum, 6 working on the ordinary functions of the stomach, states 

 that undoubtedly activity does not cease at zero. Fick and Murisier c 

 state that the gastric juice of the pike can digest proteid at 0° C, and 

 Hoppe-Seyler/ who studied the same fish, concluded that not only 

 did digestion proceed at zero, but it was most rapid at 20° C, and quite 

 active at 15° C. Krukenberg, 6 on the other hand, finds just the oppo- 

 site — that 40° C. is the more favorable temperature, and his work is 

 confirmed by Luchhau/ 



Apparently the resistance to cold is not limited to proteolytic 

 enzymes, since Kastle and Loevenhart ? have noted that lipase, though 

 splitting fat most rapidly at 40° C, is still active at —10° C, but 

 its action is much slower. At 40° C, for example, 1 1.29 per cent of fat 

 was hydrolysed, while at — 10° C. only 0.70 per cent was changed. 



THE ACTION ON FLESH OF BACTERIA AND ENZYMES AT LOW TEMPERA- 

 TURES. 



Review op the Literature. 



A review of the chemical, bacteriological, and histological data 

 recorded in connection with the analysis of the market cold-storage 

 chickens made in this laboratory indicates that undoubtedly a certain 

 amount of chemical change, and depending upon it certain histological 

 alterations, go on at temperatures far below the freezing point. They 

 have proven, also, that even four years at such low temperatures are 

 not sufficient to render the flesh of chickens germ-free, and, judging 

 from the work which has already been reported by various investi- 

 gators, it seems probable that both bacteria and enzymes will resist 

 intense cold for long periods, only thawing and a rise in temperature 

 being needed to cause a rapid resumption of activities. 



Some recent contributions to our knowledge of bacterial life at tem- 

 peratures below zero would indicate that, if the organisms are pro- 



«Loc. cit. 



& liber den Einfluss niedriger Temperaturen auf die Funktionen des Magens, Zts. 

 Biol., 18 (Neue'Folge, 10): 433. 



c Verhandlungen der Wurzburger physiol. med. GeselL, 1872, N. F. 2: 122. 



d Pfl tiger' s Archiv gesam. Physiol., 14- 395. 



e Versuche zur vergleichenden Physiologie der Verdauung mit besonderer Beriick- 

 sichtigung der Verhaltnisse bei den Fischen, Untersuch. aus dem physiol. Inst, zu 

 Heidelberg, 2: 395. 



/tlber die Magen- und Darmverdauung bei einigen Fischen, Inaug. Diss. Konigs- 

 berg, 1878. 



srAmer. Chem. J., 1900, 24: 491. 



