140 APPLIED BACTERIOLOGY FOR NURSES 



toxin which acts on the nerve-cells, but which is, fortun- 

 ately, easily destroyed by heat. The appearance of the 

 food gives no warning, although there may be a slight 

 rancid odor. 



Another organism which may cause trouble is the 

 Bacillus proteus vulgaris. This also does not alter the 

 appearance of the food; boiling renders its toxin harm- 

 less. This explains why botulinus and proteus infections 

 are almost entirely caused by the eating of sausages 

 and ham, which in Northern Europe are smoked, but 

 not cooked. 



Anthrax has been known to be conveyed to man 

 through the meat of calves or cattle suffering from the 

 disease, as well as through gelatin made from calves' 

 feet. As anthrax spores are very resistant to heat, 

 ordinary boiling may not suffice to kill them. 



Fish, as well as meat, can be the carrier of infection. 

 This may be due to sewage contamination of the water 

 (e. g., oysters spreading typhoid fever), or it may be due 

 to the development of poisonous bacteria in smoked or 

 canned fish. 



Milk, as stated before, is an excellent culture-medium 

 for bacteria, and may, consequently, be responsible for 

 certain epidemics of poisoning. Apart from such 

 diseases as typhoid, there are on record certain epi- 

 demics of "milk poisoning," notably one in Christiania 

 in 1888, which numbered 6000 cases in three weeks. 

 A colon-like bacillus has been isolated from some of these 

 epidemics. What applies to milk is true also of the 

 milk products, notably, cheese and ice-cream; poisoning 

 by these is due to the presence of bacteria which belong 

 to the colon group. 



