

BACTERIA IN SMALLPOX. 463 



discovered independently by Klein and Copeman, and 

 at present sub judice, may afford better results. Klein ob- 

 served this organism in lymph taken from a vaccine pustule 

 in a calf on the fifth and sixth days, in human vaccine 

 lymph on the eighth day, and in lymph from a smallpox 

 pustule on the fourth day. To demonstrate the bacilli, cover- 

 glass films are dried and placed for five minutes in acetic 

 acid (i in 2), washed in distilled water, dried, and placed in 

 alcoholic gentian-violet for from twenty-four to forty-eight 

 hours, after which they are washed in water and mounted. 

 Copeman and Kent also found the bacilli in sections of 

 vaccine pustules stained by LofBer's methylene-blue, or by 

 Gram's method. The organisms are .4 to .8 //, in length, 

 and one-third to a half of this in thickness. They are gener- 

 ally thinner and stain better at the ends than at the middle. 

 They occur in groups of from three to ten in both the lymph 

 and the tissues. In the centre of the protoplasm there is 

 often a clear globule, which is looked on as a spore. They 

 have hitherto resisted attempts at cultivation, a fact which is 

 rather in favour of their non-saprophytic nature, but recently 

 (April 1897) Copeman has announced that he has succeeded 

 in growing them on artificial media. The facts that this 

 bacillus is one hitherto not recognised microscopically, that 

 it exists in the pustules, the contents of which are probably 

 the means by which the disease naturally spreads, that it 

 resists artificial cultivation, that the possession by it of 

 spores explains some of the characteristics of vaccine 

 lymph (resistance to drying, etc.), make its further investi- 

 gation a matter of considerable interest. 



Various observers have described appearances in the 

 epithelial cells in the neighbourhood of the smallpox or 

 vaccine pustules, which they have interpreted as being 

 protozoa. Thus Ruffer and Plimmer describe as occurring 

 in clear vacuoles in the cells of the rete Malpighii at 

 the edge of the pustule, in paraffin sections of vaccine 

 and smallpox pustules carefully hardened in alcohol, 

 and stained by the Ehrlich-Biondi mixture, small round 

 bodies about four times the size of a staphylococcus 



