From investigations conducted some years ago by order of the government, and pub lished iu several of the Reports of the .11edical Officer of the Privy Council, it appears that amongst the poorer classes, vaccination is often so imperfectly performed as to leave no mark, and to exert no protective power. Mr. Marson of the binall-pox hospital believes that with good lymph, and the observance of all precautions, a good vaccinator should not fail of success in his attempts to vaccinate above one in 150 cases; while Dr. Seaton puts one failure as a fair proportion in 170 cases.
The official inquiries above referred to, in the course of which the arms of nearly half a million vaccinated children were examined, prove, says Dr. Seaton, who was employed in the investigation, the great extent to which imperfect or insufficient vacci nation has obtained: taking the country throughout, not more than one child in eight was found to be so vaccinated as to have the highest degree of protection that vaccination is capable of affording; and not more than one in three could, on the most indulgent esti mate.' be considered as well protected. The main causes of this imperfect success were the following: "(1) The frequency with which practitioners, instead of attempting, fully to infect the system, had been satisfied with insertions of lymph sufficient to pro duce only one, two, or three ordinary vesicles; (2) the want of due attention to the selection of the lymph used in vaccinating; (3) carelessness and clumsiness in the per formance of the vaccination, so that, if the operation did not wholly fail, it very fre iuently resulted in a less degree of effect than it had been the aim of the operator to produce; and (4) the great and unnecessary extent to which the use of preserved and conveyed lymph was substituted for vaccination direct from the arm."—Seaton, op. sit., p. 503. The following observations made by Drs. Buchanan and Seaton during the epidemic of small-pox in London in 1863, on upwards of 50,000 children in various national and parochial schools, workhouses, etc., are of such extreme importance that we make no apology for inserting them. Some of the children had never been vacci nated; the large majority had been vaccinated in various manners and degrees. Of every 1000 children without any mark of vaccination, no fewer than 360 had scars of small pox; while of every 1000 children who had evidence of vaccination, only 1.78, on an -average, had any such traces: and with regard to the quality and amount of the vacci• nation, it was found that, of children having four or more cicatrices, only 0.62 per 1000 had any trace of small-pox; while of those who had a single bad mark, 19 per 1000 were scarred by small-pox. Hence the best vaccination was more than 30 times as protective as the worst, and the worst was more than 47 times better than none at all. The import ance of the completeness of the vaccination, as shown by the cicatrices, is also well shown by the results obtained by Mr. Marson. From the study of more than 15,000 cases at
the small-pox hospital, he finds that while the unvaccinated died at the rate of 37 per "cent, the vaccinated have died at the rate of only 6,1 per cent; the mortality among those with four or more scars being only 0.55, while that among those with only a single scar was 7.73 per cent; so that, while the average risk which vaccinated persons run if they do catch small-pox is about a of the risk run by unvaccinated persons, well vaccinated persons run less than part of the risk. It must further be borne in mind that, while few unvaccinated persons do not at some period of life sustain an attack of small-pox, the cases are comparatively rare in which a well-vaccinated person catches the disorder; so that the protective power of vaccination shows itself iu two ways, viz.: .(1) in shielding the constitution, in the great majority of cases, from any kind of an attack of small-pox; and (2) in the exceptional cases, of so modifying the disease as almost invariably to deprive it of danger to life, or of those terrible disfigurements which the unmodified disease so frequently leaves behind it.
With regard to the subject of it has been amply demonstrated that its utility and necessity stand upon no speculative reasoning, but upon the broad basis of experieuce and observation. This operation, should be performed with the same care and pains as primary vaccination, nor should it be left to periods when small-pox is epidemic, but should be performed on all persons after puberty, and this is the more necessary for the primary operation is often very imperfectly performed. During an epidemic of small-pox, even young children, if the marks of the primary vaccination are at all imperfect, should most decidedly be re-vaccinated. In re-vaccinating it must always be remembered that "the local results of re-vaccination of any individual give us absolutely no information whatever as to the constitutional condition in which the re-vaccinated person was with regard to the liability to contract small-pox." Much has been written regarding the dangers of vaccination; and the well-known Rivalta case, in which an infant thus communicated syphilis to a whole population in a remote district of Piedmont (sec SYPFIILIS); and the death some years ago of a distin guished middle-aged baronet from (as it was alleged) vaccination with impure lymph, have directed special attention to the subject. For the discussion of this subject we must refer to Mr. Simon's Papers relative to the History and Practice of Vaccination; and we will only remark that those who have had most to do with vaccination, and thoSe who have had the most extensive experience in the diseases of children, concur in the belief of the non-communicability of disease by this operation.