600 EXPERIMENT STATION RECORD. 



came from some substance added in the process of manufacture, probably carbonate 

 of ammonia, because of the use of the oleomargarine in pastry making. — f. w. woll. 



Parchment paper containing- boric acid, K. Fischer (Ztschr. Untersuch. Nahr. 

 a. Genu8smtl., 8 (1904), No. 7, p. 417). — Only 17 samples of parchment paper out of 

 a total of 124 samples examined by the author were found entirely free from boric 

 acid or borates. One hundred and one samples gave a strong reaction and 6 samples 

 a faint reaction for boric acid. 



Four samples examined quantitatively contained from 0.384 to 1.130 gm. of boric 

 acid per 100 gm. of paper. It is shown that parchment paper of this kind may con- 

 taminate oleomargarine (or butter) which is wrapped therein to such an extent that 

 the outside layers of the same will give a decided reaction for boric acid. — f. w. 

 woll. 



The relation of bacteria to the flavors of Cheddar cheese, L. A. Rogers 

 (U.S. Dept. Agr., Bureau of Animal Industry I!»/. 62, j>j>. 38, fig. 1). — The physical and 

 chemical changes taking place, in the ripening of cheese and the causes of these 

 changes are discussed and concisely summarized. The appended bibliography fur- 

 nishes references to 21 articles used in this review. In addition considerable experi- 

 mental work is reported, the results of which are stated briefly by the author in his 

 summary of the bulletin as follows: 



" In this paper are given the results of bacteriological investigations made on three 

 pairs of duplicate cheeses; one cheese of each pair was held at a low temperature (8 

 to 12° C. ) and one at a comparatively high temperature (23° C. ). In all cases the 

 high-temperature cheeses ripened rapidly and soon developed a strong overripe 

 flavor, while the low-temperature cheeses ripened slowly and retained an agreeable 

 flavor for a long time. The bacteria in the high-temperature cheeses decreased rap- 

 idly, and before the cheeses were thoroughly ripened had reached unimportant 

 numbers. The increase in amids and ammonia continued after the bacteria had 

 nearly disappeared. In the low-temperature cheeses the decrease of the bacteria 

 was slower and more gradual, but continued until the number present was compara- 

 tively small. There was no increase in bacteria in any cheese at any time. 



"The total bacteria was made up almost entirely of bacteria of the lactic class. 

 In one pair of cheeses, at least, this included a lactic-acid-forming bacterium, lique- 

 fying gelatin very slowly and bringing about a slight proteolysis of casein in milk if 

 the acid was neutralized. Gelatin-liquefying bacteria were present during the first 

 few days of the ripening in considerable numbers; after a rapid initial decline they 

 persisted in comparatively small numbers, but in the course of time usually disap- 

 peared almost entirely. In all cases the high initial number was made up almost 

 entirely of a coccus forming on gelatin small, round colonies with a saucer-shaped 

 liquefaction. There was no differentiation, qualitative or quantitative, in the bacteria 

 that could account for the marked differences which existed between the high and 

 the low temperature cheeses. 



" Autodigestions of these cheeses at different periods of the ripening, made in a 

 way that excluded the action of organisms without inhibiting the activity of the 

 enzyms, indicated that — 



" (1) In the fresh cheeses bacterial enzyms were present in amounts sufficient to 

 produce only a slight increase in the amids and ammonia. 



" (2) In the ripe cheeses bacterial enzyms were present in quantities sufficient to 

 produce a marked increase in amids and ammonia. This was true of all the cheeses. 



"(3) Bacterial enzyms were formed at an earlier period and in greater quantity 

 in the high-temperature cheeses than in the cheeses ripened at a low temperature. 



'"Certain of the liquefying bacteria were able to secrete proteolytic enzyms, which, 

 when added to sterile water suspensions of cheese, caused a marked increase in the 

 annOs and ammonia. A lactic-acid bacterium which was able to digest neutralized 



