398 MICRO-ORGANISMS AND DISEASE [chap. 



microbe by the character and aspect of its young colonies in 

 gelatine 1 and Agar, and by not being pathogenic. Our 

 organism is as strongly pathogenic as that of malignant 

 oedema, from which, however, as pointed out above, it 

 differs, both morphologically and culturally, in several 

 important points. 



Bacillus variola — vaccinia. — In the Report of the Medical 

 Officer of the Local Government Board for 1892-1893 I 

 described a peculiar extremely minute bacillus as occurring 

 in the calflymph and in human variola lymph during 

 the early phases ; in the calf-lymph 72 to 96 hours after 

 vaccination, in the human variola during the third or fourth 

 day ; in both instances the lymph was collected aseptically 

 and only clear lymph and as much as possible without 

 any epidermal adnexa was used for film specimens ; after 

 heating and treatment with 30 p.c. acetic acid for some 

 minutes, were subjected to prolonged staining in alcoholic 

 gentian violet. Some of the films of calf-lymph (collected 

 after removal of the epidermis as a whole) showed an 

 abundance of these minute bacilli, generally in small and 

 large masses ; some of the specimens look like film speci- 

 mens of an artificial culture (Figs. 159 and 160). Lymph 

 of early human variola vesicles showed the same bacilli, but 

 not so abundantly. Calf-lymph of later stages (five or six 

 days old) showed no bacilli or only here and there a trace. 

 In the bacilli, when abundant, forms may be recognised in 

 which some globules of the nature of spores were present, 

 in Fig. 161 this is shown in the bacilli magnified 2000. The 

 presence of these spore-like bodies and the absence of the 

 bacilli in the lymph of later stages led me to the conclusion 

 that we have here to deal with a spore-forming bacillus, and 



■• The colonies of Botkin's bacillus butyricus grow slower, and are 

 in their early phases more opaque and distinctly filamentous. 



