40 MILK AND THE PUBLIC HEALTH chap. 



(clotting and souring) they render it unsaleable, and as such 

 are a valuable check preventing the sale of very stale milk. 

 But for the presence of this group of organisms it is quite 

 possible that milk laden with other and possible pathogenic 

 bacteria might be kept and sold even in a much staler condi- 

 tion than it is at present. This aspect of the subject is also 

 dealt with under preservatives in milk and in relation to 

 pasteurisation. 



Geoup 4. — The Spoeb-beaking Bacteria in Milk 



Under this group of spore-bearing bacilli found in milk 

 are included a number of different groups which are only 

 associated together here as a matter of convenience. Some 

 of them are strict anaerobes, others strict aerobes. 



Very little work appears to have been carried out upon 

 the presence, varieties, and distribution of the anaerobic bacilli 

 in milk. Barthel,^ in Stockholm, investigated the obligate 

 anaerobes in milk. He found that they were comparatively 

 rare in ordinary milk samples when 15 and 20 c.c. were 

 examined. They were much more numerous in summer than 

 in winter. The organisms isolated were either B. lutrificus 

 (Bienstock) or a bacillus which Barthel considered to be iden- 

 tical with the bacillus of Schattenfroh and Grassberger. B. 

 lutrificus was isolated by Bienstock from faeces. Both are 

 spore-bearing varieties. 



From the public health point of view the presence and 

 distribution of B. enteritidis sporogenes is of chief interest. 



£. enteritidis sporogenes. — An anaerobic bacillus isolated by 

 Klein in 1895. It was originally isolated by Klein from the 

 evacuation of patients suffering from an epidemic of diarrhoea 

 in St. Bartholomew's Hospital, London. It has, however, now 

 been established that it is widely distributed and had nothing 

 to do with the outbreak. It is a natural inhabitant of excreta 

 and present in considerable numbers. For example, Houston 

 found the spores 1 to 10 million per gramme of human faeces. 

 The writer has found the spores fairly abundant in animal 

 excreta, that of the horse, cow, pig, and sheep being examined. 

 In the cow, numbers varying from 10 to 1000 spores per 



1 Centralbl.f. BaU., 1910, Abt. II. xxvi. p. 1. 



