SMALL-POX AND VACCINIA 255 



the introduction of vaccination. The leading points in 

 connection with the question of the identity of small-pox 

 and cow-pox are the following: There is no doubt that 

 cow-pox can be communicated to human beings, in whom 

 it produces an eruption limited to the inoculation point, 

 and only gives rise to very trifling general symptoms. 

 Against the view that vaccinia is modified small-pox is the 

 fact that in human beings it never gives rise to a general 

 eruption. With regard to the result of inoculating cows 

 with human variola, it has been denied by many authorities, 

 notably Chauveau, that the transference results in cow-pox. 

 Many observers have, however, claimed to have accom- 

 plished the transference, including, in this country, Klein, 

 Copeman, and Simpson. The evidence in favour of this is 

 very strong. The general results of the experiments of 

 these workers are as follows : When a series of calves are 

 inoculated with a suspension of variolous crusts in brine, 

 redness and swelling appear at the point of inoculation, but 

 there is not much reaction. If the lymph, however, is 

 squeezed from such reaction as does occur, and is inoculated 

 into other calves, it wUl be found after a few such passages 

 a local reaction takes place indistinguishable from that 

 caused by true cow-pox- lymph. On using this variolated 

 lymph for human vaccination results are obtained identical 

 with those from true vaccine lymph. Thus, it will be seen 

 that the evidence in favour of the identity of variola and 

 vaccinia is very strong. In Germany much of the lymph 

 used for vaccination is that derived from the inoculation of 

 calves with variolous matter in . the manner described 

 above. 



Organisms Associated with. Small-pox and Vaccinia. — Cohn, 

 Weigert, Burdon Sanderson, and others, early pointed out 

 the presence of bacteria in lymph. The most common 

 bacilli found in the crusts and lymph of variola and vaccinia 



