PATHOGENIC ORGANISMS. 451 



Soapy Milk. After a few hours milk has been known to 

 acquire a fishy odour, alkaline reaction, and soapy taste. Herz 

 regards this as due to a disease of the cow, and has found that 

 such samples have a high specific gravit)^ ; Weigmann has iden- 

 tified an organism, which he also found in the straw used as a 

 litter, which gave a soapy taste to milk. 



Moulds. White mould (Oidium lactis) is very commonly 

 found on sour milk ; if forms a tough white skin on the surface 

 which is entirely formed by the hyphse and mycelium of the 

 mould. A brown mould, which penetrates down into the milk, 

 is sometimes observed. Green moulds, Penicillium glaucum, and 

 other species, also grow on milk, and are the colouring agents 

 of some cheeses e.g., Eoquefort and Gorgonzola. Camembert 

 cheese is ripened by moulds. 



Pathogenic Organisms Conveyance of Disease through 

 Milk. If, as already mentioned, a cow is suffering from tuber- 

 culosis of the udder, the bacillus passes into the milk. It has 

 been proved that the organism retains its toxic properties, and 

 to this cause the bulk of cases of infantile tubercular intestinal 

 disease can be traced. Tuberculosis is by no means an uncommon 

 disease in cows. Evidence was given before the Royal Com- 

 mission on Tuberculosis that in Copenhagen and Berlin, where 

 all animals before being slaughtered are examined systematically 

 by veterinary experts, the percentage of oxen and cows affected 

 with tuberculosis was 17-7 and 15-1 per cent, respectively of the 

 total number examined. In many herds the number exceeds this ; 

 on one farm as many as 80 per cent, of the cattle were affected. 



In a large proportion of the cattle the disease did not affect 

 the milk-producing organs, and in these the milk did not contain 

 the tubercle bacillus ; in a very noticeable proportion the milk 

 was, however, affected. As there is no certainty that the disease 

 may not spread to the udder, even though the bacillus be not 

 detected in the milk, the presence of tuberculosis in a cow should 

 always be taken as a sign of danger. 



Tuberculosis of the lungs may cause the milk to be affected ; 

 the cow does not expectorate but swallows the pulmonary 

 secretions, and the bacilli pass through the alimentary tract and 

 appear in the faeces. Uncleanly milking may cause faecal con- 

 tamination and thus introduce the bacilli of tuberculosis. 



On the Continent and in America this subject has received 

 much more attention than in this country, but now that the 

 report of the Royal Commission on Tuberculosis is completed, 

 it may be expected that legislation will follow, which will mini- 

 mise this cause of infection. 



An obvious means of preventing infection by tuberculosis is 

 to remove the diseased cattle, and only use healthy cows as the 



