104 REPORT— 1839. 



advantages to be derived from the possession of positive guides to the 

 situation of the nerves and arteries which may be concerned in acci- 

 dents and operations. Mr. Alexander Walker also studied the subject 

 as early as 1804. 



Dr. Macartney then described a remarkable case showing the truth 

 of his views, and adduced examples from his OAvn experience of the fa- 

 cility of applying them in practice. 



On the Cause of the Increase of Small-Pox, and of the Origin of 

 Variola- Vaccinia. By Dr. Inglis. 



Dr. Inglis stated, that variola was every year upon the increase, the 

 cause of which was, not that vaccination was inefficient, or that the vi- 

 rus had degenerated, but that, from a long immunity from small-pox, 

 the public had ceased to think vaccination necessary. He adduced 

 proofs from the Cow-pox Institution of Dublin, from foreign reports, 

 and from the innumerable cases of successful re-vaccination, that the 

 vaccine virus had not degenerated, but that the human system did un- 

 dergo a change during some unknown number of years. In Ripon, 

 during the year 1837, variola prevailed extensively as an epidemic, and 

 Dr. Inglis observed at that time innumerable eases of varicella; those 

 affected with chicken-pox were principally children upon whom vacci- 

 nation had not recently been performed, and those who had chicken- 

 pox, without vaccination, seldom contracted small-pox. The two dis- 

 eases appeared to Dr. Inglis to arise from one cause. Many cases, to 

 prove the convertibility of the one disease into the other, were adduced. 

 Dr. Inglis, having full faith in the efficacy of vaccination and of re-vac- 

 cination, after first inserting the vaccine lymph, inserted into his arm 

 in several places, the virus from variolous patients in different stages of 

 the disease, and, in one instance, from a patient who was dying from the 

 disease, but in none of them did he succeed in inducing an eruption ; 

 the inflammation and pruritus was considerable for a day or two, but 

 then gradually subsided. That the vaccine virus, therefore, decreases 

 in its preventive influence, is a supposition at least difficult of proof; for, 

 from the beginning, this prophylactic pow^er was imperfect in different 

 degrees, and even an attack of small-pox itself is no certain security 

 against a second or even a third attack. The next point in the paper 

 was to show that the two visitations of small-pox and vaccination could 

 and did go on in the system at one and the same time, distinct cases of 

 which were brought forward. Now, since two dissimilar contagious ir- 

 ritations cannot run their course together without the one impeding the 

 other for a time. Dr. Inglis was led to suppose that variola and variola- 

 vaccinia had the same common origin, or rather that vaccinia sprung 

 from variola. The paper concluded by the following brief summary : — 

 1st. That small-pox is decidedly on the increase, and that during each 

 successive epidemic there is an increase of variolous patients from 

 amongst those who were vaccinated in infancy. 2nd. That the vac- 

 cine virus is as effectual now as ever it was, but that re-vaccination is 

 necessary after a period of years, as yet unknown. 3rd. That the same 



