20 The Philippine Journal of Science isis 



variola, but also with sheep-pox and horse-pox. The reaction to all these 

 procedures is, without exception, the production of a local pustular erup- 

 tion, which, when inoculated back into the original animal, likewise causes 

 nothing but a local affection capable of further cultivation throughout 

 the species. Finally, the temporary or permanent protection conferred 

 upon individuals of any species (human or animal) by successful inocula- 

 tion with any of these varieties of virus extends to all forms of smallpox, 

 whether they be animal or human. 



It would appear from this that the pock-causing element is 

 common to these diseases and that they are mutually protec- 

 tive one against the other; yet that smallpox and sheep-pox, 

 both highly contagious and highly mortal diseases in their re- 

 spective natural hosts, are not the same is indicated by the fact 

 that man does not get sheep-pox and sheep do not get smallpox. 

 It is further indicated by the pathologic findings in sheep- 

 pox.(l3)(i4) 



While touching the relationship of animal poxes we may here 

 mention, on the authority of Doctor Ruediger, in charge of the 

 serum laboratory, Bureau of Science, Manila, that the strain of 

 vaccine virus now used by that Bureau and by the Government 

 of the Philippine Islands, a strain with which almost 7,000,000 

 vaccinations have been made with great success, was derived 

 from a fatal case of human smallpox in 1908, having been passed 

 ftrst through monkeys, and from the second monkey to a heifer, 

 and from the fifth heifer to man. 



Gauducheau(i5) reports a similar experience from French 

 Indo-China. 



For many years the common origin of smallpox and vaccinia 

 was disputed, largely because numerous able investigators were 

 unable to inoculate cattle satisfactorily, or at all, with variolous 

 lymph. 



Kelsch(5) reports 20 failures in 1909 and 1910. 



Copeman(i6) gives a good account of the early work. 



At present it is conceded that direct inoculation from vario- 

 lous man to cattle is often, if not usually, unsuccessful, and 

 the more satisfactory method of obtaining variola-vaccine is 

 first to inoculate from man to monkey and later from monkey 

 to cattle, although Freyer(i7) reports success from the use of 

 rabbits instead of monkeys. From this it might be presumed 

 that the bovine host is normally less susceptible and more re- 

 sistant to smallpox virus than is the monkey, and the same is 

 probably true of vaccine virus, as in our experience, with 16 

 monkeys and 9 cattle, the vaccine pustules are uniformly much 

 larger in the monkey, as they also are in man. 



