206 A MANUAL OF BACTERIOLOGY 



These investigations prove that cows suffer from 

 scarlatina ; that the specific microbe circulating in 

 the blood of the diseased animals contaminates the 

 milk; and that such milk conveys the disease to 

 human beings. The disease has also been directly 

 communicated to man by inoculation with the virus 

 from the ulcers on the teats and udders. In a 

 particular case, recorded by Dr. J. Cameron, 1 a man 

 received the virus of scarlatina into a recent scratch 

 upon his forefinger while milking a diseased cow. 



As both human beings and cows are liable to be 

 attacked with scarlatina, and as the milk of the 

 latter (when diseased) is capable of producing an 

 extensive outbreak of the disease in human beings, 

 it is advisable that milk should be boiled before use. 

 .This destroys any microbes which may be present. 2 



LEPROSY. 



The microbe of this disease is Hensen's Bacillus 

 leprce. It measures from 4 to 6 //, long and about 1 

 /i wide (Fig. 33, 2), and it occurs in masses within 

 the large leprosy-cells of the nodules of the skin 

 and organs, as well as of the mucous membrane 

 of the mouth, palate, and larynx. Two types of 

 leprosy are described the anaesthetic and tuber- 

 cular varieties ; the first variety is more frequently 

 seen in the tropics, the latter in temperate climates. 

 In the anaesthetic variety the bacillus is present in 



1 Transactions of Epidemiological Society, 1885-6. 



2 For full details of Klein's researches see the Reports of 

 Medical Officer to Local Government Board, 1885-6 ; 1886-7 ; 

 1887-8; 1887-9. 



