684 SUPPLEMENTARY APPENDIX. 



all the cases of " grease " which by inoculation were found to give rise to 

 vaccine vesicles in man were cases of true horse-pox. And this at least 

 must be said, that no investigations as complete and varied as those which 

 have been carried out with regard to the development of vaccine vesicles 

 through the inoculation of small-pox matter, have been carried out with 

 regard to the alleged development of vaccine vesicles by the inoculation 

 of other material, such as the matter from the eruptions of the sheep-pox, 

 the cattle plague, and the like. Nor have there been like extended in- 

 quiries as to the production of vesicles resembling those of vaccine by the 

 inoculation of small-pox matter into animals other than the cow or the 

 horse ; such results as have been obtained by observers are conflicting. 

 There is still room for much inquiry ; meanwhile it may be said that, in 

 any case, the evidence in favour of a possible transformation of small-pox 

 into vaccine is sufficiently strong to remove the force of the theoretical 

 objection to the power of vaccination to secure immunity towards small- 

 pox, on the ground that the two diseases are absolutely distinct. 



Risks of Vaccination. 



It must not be forgotten that the introduction into the system of even 

 a mild virus, however carefully performed, is necessarily attended by the 

 production of local inflammation and of febrile illness. If these results 

 did not in some measure follow, the practice would probably fail in its 

 protective influence. As a rule, the inflammation and illness are of a 

 trifling character .; in exceptional cases, however, they may exhibit more 

 severity, and, as certain facts submitted to us in evidence have shown, 

 there are cases, though these are rare, where a general eruption may 

 follow vaccination. 



In order to determine how far the risk of erysipelas is a necessary 

 incident of vaccination, what is the extent of that risk, and how it may 

 best be avoided, it is necessary to consider the various circumstances 

 which may occasion erysipelas and allied diseases in the case of vaccinated 

 children. It is established that lymph contains organisms, and may 

 contain those which under certain circumstances would be productive of 

 erysipelas. It is therefore possible that some contagious material (the 

 specific virus of erysipelas, for instance,) may be conveyed at the time of 

 vaccination, owing either to its presence in the lymph employed, or to its 

 being conveyed by the vaccinator himself, or by those with whom the 

 child comes in contact at the time of vaccination. We believe that the 

 cases in which the virus is conveyed at the time of vaccination are rare. 

 It has, however, in some instances been clearly established, the immediate 

 occurrence of erysipelas in several co-vaccinees making it practically 

 certain that some virus was conveyed at the time of the operation. In 

 some instances where this has been the case, and there is every reason for 

 believing that the contagion was conveyed through the medium of the 

 lymph, it is nevertheless in evidence that the vaccinifer did not display 

 anything more than a slightly inflamed arm. The scrupulous avoidance 

 of inflamed arms in vaccinifers will do much to reduce the risk of 

 conveying erysipelas in the act of vaccination (a risk which, as we have 



