686 EXPERIMENT STATION RECORD. [Vol .37 



dirty barns. They simply point to the fact that the large numbers of bacteria 

 commonly found in millj do not have their origin in the barn." 



Fishiness in evaporated milk, B. W. Hammer {Iowa Sta. Research Bui. S8 

 (1917), pp. 2^5-2 Jfb, fig. 1). — The author briefly reviews recent literature per- 

 taining to fishy flavor in milk and butter and reports results of a study of 

 the cause of the very fishy odor and flavor that had developed in one can of 

 evaporated milk. From this can an organism was isolated that was capable 

 of producing fishiness in milk, cream, or evaporated milk into which it was 

 inoculated. In inoculated milk there was, in addition to the development of 

 a fishy odor, a coagulation and a rapid digestion. The isolated organism when 

 inoculated into butter, either directly or into sweet or soTir cream either pas- 

 teurized or sterilized before churning, failed to produce fishiness. In some 

 lots of butter, salt was used while other lots were unsalted. The counts made 

 showed that the numbers of bacteria per gram deceased throughout the hold- 

 ing period with butter made from sour cream and with salted butter made 

 froin sweet cream, while with un.^alted butter made from sweet cream there 

 was an increase which was followed by a decrease. 



A description is given of the organism under the name Bacillus ichthyosmius, 

 apparently a new species closely related to the Proteus group. It is suggested 

 that the organism, which fails to resist heat, may have gained entrance to this 

 can after heating, probably through some hole in the metal which was sealed 

 shortly after sterilization. 



The manufacture of cottage cheese in creameries and milk plants ( U. S. 

 Dcpt. Agr., Bur. Anim. Indus. [Pub.]. {1911), pp. .}). — This circular points out 

 the advantages of pasteurizing skim milk for the purpose of controlling the 

 flavor of cottage cheese, describes in brief the methods of manufacture, pack- 

 ing, and marketing, and gives an estimate of the yield of cottage cheese to be 

 expected from skim milk. 



Simple directions for making cottage cheese on the farm ( TJ. S. Dcpt. Agr., 

 Bur. Aniw. Indu.<<. [Pub.], {1917), pp. S). — Brief directions are given for the 

 utilization of skim milk for making cottage cheese on farms. 



A substitute for litmus for use in milk cultures, W. M. Clark and H. A. 

 LuBs {U. S. Dcpt. Agr., .Jour. Agr. Re.'<earch. 10 {1917). .Vo. S, pp. 105-111).— 

 "The color changes which occur in litmus-milk cultures may be due to changes 

 In the hydrogen-ion concentration of the medium, or to reduction, or even 

 destruction of the dye. If it is the degree of acid or alkali fermentation which 

 is sought, it is advisable to u.«?e an indicator which will not be affected except 

 by a change in the hydrogen-ion concentration." Dibromoorthocresolsulfon- 

 phthalein, for which the short name bromcresol purple is suggested. Is said 

 to fulfill this condition. The authors have describe<l the preparation of this 

 compound (E. S. R., 36. p. Ill) and have suggested its use in the determina- 

 tion of hydrogen-ion concentration (E. S. R.. 37. p. 506.) For ordinary indi- 

 cator purposes a 0.04 per cent aqueous solution of the monnsodium salt Is 

 recommended, but as a stock solution for the present purpose a solution of 

 the salt containing 0.5 per cent of the acid is suggested. A method is given 

 for the preparation of this solution. 



In comparing litmus and bromrresol purple as indicators in milk cultures 

 It Is stated that " litmus undergoes a temporary reduction during sterilization 

 in the presence of milk. Bromcresol purple does not. The coloring power of 

 litmus is relatively weak ; bromcresol purple in very high dilution is useful. 

 Litmus and azolltmin are Indicators of uncertain composition: bromcresol 

 purple Is a definite individual compound obtainable in crystalline form and 

 therefore reproducible. Its cost is not excessive. 



