No accepted or acceptable explanation of the phenomenon has yet been put forward. It has been suggested by the various authors and particularly by Fridericia et al. (1927) that bacterial synthesis of vitamin B in the intestine of the rat may be the explanation of the condition. Schieblich & Rodenkirchen (1929) have described a “vibrio-like” organism which they claim to be responsible for refection, but this finding has so far not been confirmed. In a recent dissertation on refection Nathan (1935) believes that the explanation is coupled with the nature of the starch in the diet rather than with an infection with a specific type of organism.

145as a result of the work described in this paper, is far more useful and promises to be of value in completing the complicated picture of the relationship between the lactic streptococci and the phages which attack them. SUMMAEY The effect of temperature on the growth in milk of several strains of Str. cremoris and their appropriate phages has been investigated. The phage races show a wider diversity of reaction to temperature conditions than do the homologous organisms. They frequently have different optimum growth temperatures quite distinct from the optimum growth temperature of the substrate organisms. Some races fail to multiply at 37° C.The implication of the results in cheese-making practice is discussed.

No abstract

IN the bacteriological examination of raw milk in England it is customary to test for coliform organisms and to regard the extent to which they occur as an indication of the care with which the milk is produced and subsequently handled.The present test is presumptive, and the presence of acid and gas in a bile salt lactose broth, containing litmus, Andrade's or other indicator is considered to denote the presence of cohform organisms. These organisms do not ordinarily occur in the udder of the cow, and under ideal conditions should not be present in milk. In practice it is rarely possible to exclude them completely, but in clean milk, handled and distributed under good conditions, their numbers, as estimated by the presumptive test, are very small, even when the milk is 24 hours old (Mattick and Stenhouse Williams (i)). In view of the fact that the presence of coliform organisms is also frequently interpreted as an indication of faecal contamination, it was felt that it would be of interest to obtain further information, using modern technique, on the types of facultatively anaerobic lactose-fermenting, non-gelatin-liquefying, Gram-negative bacteria occurring in milk and in bovine faeces.Rogers, Clark and Davis (2) divided the Gram-negative lactose-fermenting bacteria into two groups, those giving a high, and those giving a low ratio of G0 2 : H 2 in a dextrose medium, and found the two groups to be present in almost equal proportions in milk. Rogers, Clark and Evans (3) found that from bovine faeces 149 out of 150 belonged to the low ratio group, but that from grain (Rogers, Clark and Evans (4)) 151 out of 166 cultures were of the high ratio type, which they recognised as Bact. aerogenes; similar lactosefermenting, Gram-negative organisms, which, however, slowly liquefied gelatin, were regarded as Bact. cloacae.Following the work of Clark and Lubs(5); Levine(6), Rogers, Clark and Lubs(7), and Koser(8) showed that the methyl red, Voges-Proskauer, indol and citric acid utilisation tests were correlated and these tests are now used to differentiate the faecal from the non-faecal coliform organisms.Koser (8) found that the citrate test gave more reliable information regarding the source of the organism under test than the methyl red and VogesProskauer tests. Chalmers (9) working on coliform organisms in milk used the classification of Stewart, and included many non-lactose-fermenting, Gramnegative, non-spore-forming organisms.