632 ACTIVE IMMUNIZATION 



point of entry of what becomes a general infection, then a small lesion 

 should suffice. This point has not been definitely settled, but statistics 

 tend to show that persons vaccinated in two or more areas develop an 

 immunity more quickly and that this immunity is more lasting. 



The subsequent care of the wound is of considerable importance. The 

 operation is usually regarded as a trivial one, and justly so, but the 

 lesion requires judicious after-treatment instead of being entirely 

 neglected, as it so often is. The severe infections are usually attribut- 

 able to gross and careless contamination of the wound. The best pos- 

 sible protection to the vaccinial ulceration is afforded by the forma- 

 tion of a hard, solid crust, due to desiccation of the contents of the 

 vaccine vesicle and pustule. Unless undue inflammation and suppura- 

 tion set in, such a crust will form. Care must be taken that the 

 crust is not subjected to mechanical violence calculated to loosen or to 

 detach it. 



Constricting shields are likely to be unsatisfactory. The adhesion 

 of the crust to the sleeve or to a piece of protective gauze will often 

 lead to forcible decrustation when the sleeve or the gauze is removed. 

 Schamberg and Kolmer 1 have found that daily applications of a- 4 per 

 cent, alcoholic solution of picric acid upon the vaccinated area after 

 the first forty-eight hours does not interfere with the success of the 

 vaccination, and lessens the degree of local inflammatory reaction and 

 constitutional disturbances by hardening the epithelial covering of the 

 vaccine lesion, and thereby decreasing the liability of extraneous 

 bacterial infection. 



A point to be emphasized is that severe lesions are unnecessary, and 

 are usually due to scratching of the vesicle or pustule and consequent 

 introduction of dirt. No doubt tetanus bacilli may be introduced in 

 this manner, the resulting scab affording the necessary anaerobic con- 

 ditions for their development. 



The Phenomena of Vaccination; Vaccinia. Immediately follow- 

 ing vaccination a slight redness appears, which usually subsides rapidly. 

 After a short period of incubation on or about the third day a slight 

 red elevation makes its appearance, and the lesion begins to burn and 

 itch. On the sixth or seventh day the abrasion becomes a small, silvery 

 gray, umbilicated vesicle with a sharply raised edge, filled with a clear 

 serum, and surrounded by a narrow red areola (Fig. 129). By the 

 tenth day the characteristic features are more marked, and the lesion has 

 usually reached its height, being accompanied by a burning sensation 

 1 Lancet, London, Nov. 18, 1911, 1397. 



