MARKET COLD-STORAGE CHICKENS. 97 



rapid in the beginning of the experiment than when there has been 

 an accumulation of the products of activity. 



Such wide and varied abilities appertaining to an enzyme as are 

 indicated by the foregoing summary demand that account be taken 

 of its action, wherever natural changes of fat are in progress, and its 

 ability to retain its activity for long periods of time and to work at 

 low temperatures makes its rdle in fat changes in cold storage an 

 important one. 



Since enzymes of varied abilities have been traced to a bacterial 

 origin it is quite reasonable to infer that those having some action 

 on fats would be so produced. Schreiber/ who has studied earth 

 bacteria, was unable to find ferments, and considers the decompo- 

 sition of fats to be dependent upon vital functions. It is then 

 affected by all the conditions which affect life. Schreiber states that 

 anaerobes split fats slightly, but their activity ceases at that point 

 and is feeble at best. Rahn b denies that anaerobes have any action 

 on fats, but admits that they can decompose glycerin. Both of 

 these authors report work on certain molds — Mucor, Penicillium — 

 and find that they cause both a rapid and a complete decomposition. 

 Among bacteria B. fluoresceins liquefaciens shows a fat-decomposing 

 power closely following that shown by molds. Rahn c has deter- 

 mined this activity as expressed by the iodin number, which was 

 considerably increased for palm fat, stearin, and butter fat. Laxa d 

 has recorded analyses covering the values usually determined in 

 fat examinations using butter fat with molds, yeasts, and fat split- 

 ting bacteria proper. The latter, with the exception of B. fluoresceins 

 liquefaciens, commonly cause a decrease in the iodin number; the 

 other fungi noted usually increased it. The Reichert-Meissl number 

 was but little changed. The acid value increased for both molds 

 and bacteria. The saponification number decreased with both. The 

 index of refraction in many instances fell when the iodin number 

 rose, and when the latter decreased the refractive index remained 

 stationary. The Hehner number for molds showed a rise. 



It will be observed that there is a distinct difference between the 

 action of molds and of bacteria on fats. This is again expressed 

 in the work of Girard, who believes that Aspergillus and Penicillium 

 act by way of an enzyme and Laxa e has demonstrated by experi- 

 ment that such is the case. With substances as complex as are fats 

 in their natural environment and with forces as delicate as fungi 



o Fettzersetzung durch Microorganismen, Arch. Hyg., 1902,-^:328. 

 &Die Zersetzung der Fette, Centrbl. Bakt., 2 Abt., 15: 53. 

 cLoc. cit., .75:422. 



dUeber die Spaltung des Butterfettes durch Microorganismen, Arch. Hyg., 1902, 

 41:118. 

 e Loc. cit. 



49078— Bull. 115—08 7 



