n8 PHYSIC 



observant mind of Jenner was attracted to the subject, 

 and his inductive acumen was exercised on the problem, 

 when lo! a means was devised by which the scourges of 

 the most loathsome and mortal disease of the time were 

 to be lightened and lessened almost to the vanishing point. 

 His strength of faith in the correctness of his inductions 

 led him to adopt the means which Nature had indicated 

 and carried out in the dairymaids of his district, and he 

 artificially followed her lead, introducing by the lancet the 

 vaccine serum or lymph provided from its natural source, 

 and afterwards from "arm to arm." 



The good results of the procedure in conferring im- 

 munity against, or so far modifying the progress of, 

 smallpox soon showed themselves, and he felt himself 

 warranted in urging its adoption in place of " inoculation," 

 which was then in favour. The subsequent experience of 

 the ameliorative influences of the procedure won public 

 confidence to such an extent that a measure enforcing its 

 general adoption was added to the statute book. 



The rationale of the process of vaccination is as yet 

 somewhat obscure, and although a great deal has been 

 thought, said, and written on the subject since the immortal 

 Jenner's introduction of it, we can scarcely, with all the 

 comparative light that has been shed on the problems 

 involved in its elucidation, say much more of "light and 

 leading" than he did. Nevertheless, and so much more 

 in consequence of this, it behoves everyone who can add 

 a ' ' mite " of thought, experience, or deduction, to do so, 

 trusting that aid, although infinitesimal may thus be 

 afforded in the interesting and important work. 



The vaccine virus, having been introduced into a sus- 

 ceptible child or individual through a sufficient "solution 

 of continuity" of its surrounding skin, passes into its 

 internal fluid-containing parts, and there incubates, pro- 

 ducing meanwhile more or less febrile, and general dis- 

 turbance according, we may say, to the intensity of the 

 action of the specific poison germs on the various impres- 

 sible and responsive body constituents, and the range to 

 which the multiplication of these germs attain and the 

 degree of toxicity to which they may reach. The period 

 of incubation passed, a more or less slow but definite 



