680 EXPERIMENT STATION RECORD. 



The composition of clotted cream, the water content of butter, and 

 analyses of 2 samples of ))utter made with a butter increaser are given. 

 The latter contained over 20 per cent of water. 



Milk preservatives, C. B. Cochran {Pennsylvania Dept. Agr. Jipt. 

 189D,2)t. 1,2'P- 2'^'^-'^<'^'9)- — The author discusses the use of l)oric acid 

 and formaldehyde in preserving- milk and the physiological action of 

 these antiseptics on man and the lower animals. The literature of the 

 subject is reviewed, tests are given for the detection of boric acid and 

 formaldehyde, and results of experiments by the author are briefly 

 noted. The antiseptic power of formaldehyde in milk was found in 

 experiments to be about 50 times as great as that of boric acid. No 

 dijS'erence was observed in the artificial digestion of pure milk and 

 milk to which formaldehyde had been added at the rate of 1 to 10,000. 

 Formaldehj'de added in large quantities (1:1,000 to 1:200) to milk at 

 the time of renneting or 6 hours before retarded or prevented coagu- 

 lation and in other respects modified the action of the rennet. Min- 

 nows and tadpoles withstood quite well a 1 to 50,000 solution of 

 formaldehyde, remaining alive from 1 to 6 days, while they died in a 

 few hours i;i a solution of corrosive su])limate of the same strength. 

 " When we bear in mind the fact that minnows are exceedingh' sensi- 

 tive to most poisons and that the formaldeh3'de must have been 

 present in the blood and in every tissue to the extent of 1 part in 

 60,000, it shows that some animal tissues, at least, stand formaldehyde 

 very well." Microscopical paramecia showed considerable ability to 

 withstand dilute formaldehyde for a time. The author prefers for- 

 maldehyde to boric acid as a milk and cream preservative, on the 

 ground that it is less injurious and that "it is impossible to use 

 formaldehyde in excessive amounts, since its presence is then betrayed 

 by the sense of taste."" Objections to the use of preservatives in milk 

 are considered. 



Investigations on the cause of the rancidity of butter, R. Rein- 

 MAXN {CtntU. Bali. u. Par., '2. Alt., 6 (1900), A^os. J, pp. IJ 1-139; 

 6, pjp. 166-176; 7.^ pp. 209-2111). — From a review of the literature on 

 the subject and the experiments covering a variety of conditions, the 

 author arrives at the following conclusions: (1) The amount of free 

 acid formed in butter bears no relation to the rancid taste and odor. 

 (2) A high content of casein and milk sugar in butter is very favor- 

 able to rancidity. (8) The oxygen of the air is not of the importance 

 in the production of rancidity in butter which has been claimed, since 

 sterile cream l)utter does not become rancid with the free access of 

 air. (1) Light does not appear to be of any importance in this con- 

 nection. (5) Under ordinary conditions butter made from sterilized 

 cream does not become rancid. Rancidity can l)e induced, liowever, 

 in a few days by working into it a very small quantity of rancid 

 butter. (6) The question as to whether the rancidity of butter is due 

 to the action of micro-organisms or ferments is still an open one. 



