338 Dr. Murray on Vaccination. 



although it is true, tliat, in greater number of instances, Small- 

 Pox after Vaccine-Pox has proved an imperfect and mitigated 

 disease, and of a safe nature when compared with regular 

 Small-Pox, yet, in others, it has not appeared to be at all 

 modified by the previous vacciriation ; and in a few instances 

 it has terminated fatally. 



Many of the failures of Vaccination have been traced by 

 Medical 3Ien to such causes as the following, — to the operation 

 having been performed with spurious or deteriorated Virus; or 

 performed when the patient was laboring under some other 

 eruptive or constitutional disorder; to the course of the Vaccine 

 action having been interrupted by the pustules being prema- 

 turely broken or punctured ; to the whofe of the lymph liaving 

 been abstracted from the pustules for the purpose of communi- 

 cating the disease to others ; to certain' conditions of tiie 

 weather opposing tlie dnc action of the virus ; arid* to 

 idiosyncracy or peculiarity existing in particular patients 

 which prevented vaccine assimilation in their constitution, 

 or overcame its protective influence ; — but it must be confessed 

 that all these have been considered unsatisfactory in many of 

 the cases ; nor can it be admitted that the Virus has become 

 less efl'ectual from i>aasing repeatedly through the human con- 

 stitution, or that the protective influence diminishes and wears 

 out by time, as some are inclined to assert ; for as far as can- 

 be observed, the Vaccine Lymph produces the same sensible 

 effects in the present day as it did at the period of its first 

 introduction ; and our experience of the permanency of its 

 influence, in the majority of cases, is complete. 



I have become impressed with the idea that Vaccination in 

 very early infancy is probably a principal cause of its failure, 

 from reflecting u|x)n the known insusceptibility of the infantile 

 constitution to contagion in general ; aud from having hatt 

 occasion to observe some very marked instances of its insuscep- 

 tibility to scarlatina during the prevalence of that disease here 

 in 1830; at which period, although children were chiefly the 

 subjects of its attack, young infants generally enjoyed the 

 privilege of exemption from it, as if their system were insus- 

 ceptible of the morbific eftect of its contagion. Of two families 

 wiio fell under my particular observation, the youngest of each 

 (babies in arms) entirely escaped, when all the rest of the 

 children were afiected ; and I heard of many other instances of 

 similar exemption. I myself did not see any child under a 

 year old who took the disease during the whole period of the 

 Epidemic — no such case occurred amongst the IVIiiitary ; and I 

 have not been able to trace more than two or three instances, in 

 civil practice, where infants at the breast became afiected, and 

 they were ail upwards of eight months old, and had the disease 

 in a very mild form, llencc I was led to infer, that a similar 



