EXPERIMENT STATION REPORTS. 235 



Relatively higher bacteriological counts were obtained on butters 

 over a year old than are usually obtained in studies of this kind, though 

 there was a fairly rapid dying off in numbers at first. 



The lactic acid bacteria appeared on the plates for a longer period 

 than is usually thought possible, though there was a gradual displace- 

 ment of the lactic acid flora by a more miscellaneous flora, among which 

 the predominant types were a liquef^ang and a non-liquefying yeast and 

 an Oidium species. 



Taking the butters as a whole, there was a slow, gradual decrease in 

 the amount of lactose present and a gradual increase in acidity, though 

 the decrease of the one was not proportional to the increase in the 

 other. 



The amount of nitrogen in the pasteurized cream butters was about 

 half that of the raw cream butters, but the percentage of nitrogen in 

 soluble form was about the same in each class of butters, though it was 

 very small in either case. 



When 12 of the typical butter organisms were inoculated into milk 

 alone and milk containing 3 per cent of salt, it was found that the 

 number of bacteria increased rapidly in both cases but more rapidly 

 Avhen salt was not present. The increase in acidity was very slight in 

 either case and of about the same amount. The action of these or- 

 ganisms upon the nitrogenous compounds of milk without and with the 

 addition of 5 per cent salt was to increase the amount of soluble nitro- 

 gen in both cases but more so without than with salt. This amount of 

 salt, however, does not retard the growth and action of these butter 

 organisms as much as might seem possible. 



[G. L. A. Ruehle] 



Research Associate Zae N. Wyant has continued in charge of Adams 

 project 2c and also she has pursued her studies on vinegar and food 

 fermentations with special reference to silage and to food preservation. 

 The results of the previous year's work are found in part in Special 

 Bulletin 98, ''Vinegar" and in Technical Bulletin 47, "Studies in the 

 heat resistant organisms of cold packed canned peas," the latter by 

 Ruth Normingtondone under the direction of Mrs. Wyant and myself. 

 The following report is made of progress during the past year: 



Silage poisoninrj: Four samples of silage suspected of poisoning 

 stock were sent in for analysis. One of these samples contained an or- 

 ganism morphologically resembling B. hotuUnns but injection of ex- 

 perimental animals gave negative results. 



fiUafje inocidatinn, fiicaniivr/ rnul saltinr/ studies — Alfalfa silaf/c: 

 Last October cut alfalfa was jdaced in two silos, two feet in diameter 

 and six feet high, made of three 2 by 2 ft. glazed sewer tile with joints 

 and bottom cemented. The alfalfa was steamed before being packed into 

 silo Ko. 2, steaming being employed to desti-oy some organisms and to 

 allow more alfalfa to be packed into the tile. The silage in botli was 

 well tramped. To silo No. 1 was added sufficient water to make the 

 fermentation anaerobic. The steaming marie the addition of water un- 

 necessary in the second silo. The alfalfa in bolh silos was covered with 

 melted paraffin. All hough ilie alfalfa in silo No. 1 was tramped until it 

 was six inches below the rim of the tile, the next day the fermenta- 

 tion became so active as to push the paraffin cover one to two inches 

 above the top of the silo. The fermentation was hardly noticeable at 



