BACTERIA IN LONDON MILK 217 



tion in regard to the distribution of B. enteritidis sporogenes, which 

 he found to be present either alone or with B. coli in 49 samples 

 out of 213. Out of these 49 samples containing B. enteritidis 

 sporogenes the organism proved to be non-pathogenic in 1 1 cases, 

 and pathogenic in 38. In eighteen instances it produced a fatal 

 result in the guinea-pigs inoculated.^ 



As a result of the veterinary inspection of the cows in London 

 cowsheds to which reference has been made, a bacteriological 

 examination was instituted and entrusted to Dr Klein, who there- 

 upon made a careful study of 100 milks derived from various 

 milk-shops in London. His findings may be quoted : — (i) seven 

 per cent of the samples of "country" milk sold in London 

 produced typical true tuberculosis in the guinea-pig; (2) eight 

 per cent, of the samples of "country" milk produced typical 

 pseudo-tuberculosis (non-acid-fast bacillus pseudo-tuberculosis of 

 Pfeiffer) ; (3) one per cent of milk samples yielded the typical 

 true B. diphtherics ; (4) one per cent contained a pathogenic 

 }'east ; and (5) out of the secretions of the cow's udder two 

 pyogenic microbes were obtained, B. diphtheroides and Strepto- 

 coccus radiatus {pyogenes).- 



In the same place Klein summarises the general knowledge 

 concerning pathogenic bacteria in milk as it was in 1901. He 

 points out that milk healthy in appearance may contain " bacteria 

 which belong to various species, and some of which when grown 

 separately in sterile milk cause rapid changes and alter profoundly 

 the character of the milk, e.g. B. lactis, Proteus vulgaris^ B. coli^ B. 

 meseniericus, spores of B. enteritidis, etc. If allowed to stand, the 

 milk containing the above mixture of bacteria exhibits, even at 

 ordinary temperatures (but in a more marked degree at tempera- 

 tures of 70 F. and above), those profound changes which are 

 popularly expressed as ' going bad,' changes caused by the rapid 

 multiplication of one or other of the above microbes. Thus, for 

 instance, if different samples of milk received and brought in a 

 sterile vessel from a shop be placed in an incubator at 37^ C, the 

 next day, or at the latest after tvvo days, the milk may be completely 

 clotted and sour, due to the growth and activity of B. coli ; or it 

 may be decomposed by Proteus vulgaris or B. mesentericus ; or it 

 may be full of gas, clotted, and with a large amount of clear whey, 

 caused by the growth of the anaerobic B. enteritidis sporogenes — 



^ Report of Thompson -Yates Laboratories (Liverpool, 1900), voL iii., part i., 

 P-37. 



* Jour, of Hygiene, 1901, vol. i., p. 95. 



