a=O+b, and O+c=O+d. That is the question for the solution of which we must appeal to scientific experiment, both at the bedside and in the laboratory, as well as to abstract reasoning. It has frequently appeared to the writer that time and quantity (dose), are not duly reckoned with in the question of the efficacy or inefficacy of Jennerian vaccination; and Pasteur seems also to lose sight of both factors in his own experiments. The great mass of medical men firmly believe that vaccination protects against variola; and, that vaccinia and variola are ALIKE is quite certain; it is only the degree of the likeness that can be subject of dispute, for both are pyrexial pustular diseases. Statistics of a number of years, nevertheless, show that variola is, in the aggregate, about as deadly as ever, allowing for a natural decrease of its vis by age; this cannot be controverted, so much must bvaccination were unipotential. The prevention of disease according to the law of similar- homoeoprophylaxis-is still struggling with its swaddling clothes, but we may reflect on the following: Two similar diseases will affect the organism similarly: they will affect the same parts, organs or tissues, and in a like manner.
If we call the two diseases a and b, and the organism O, then if a fall upon O, and affect it positively (positive effect=c), this effect of a upon O, c will be like the effect of b (=d), for a and b are alike.
Now if we admit that the similarity between a and b is enough to render them effectively equal, potentially congruent, then we should say a=b, and therefore c=d. Consequently O+a=O+b, and O+c=O+d.
That is the question for the solution of which we must appeal to scientific experiment, both at the bedside and in the laboratory, as well as to abstract reasoning.
It has frequently appeared to the writer that time and quantity (dose), are not duly reckoned with in the question of the efficacy or inefficacy of Jennerian vaccination; and Pasteur seems also to lose sight of both factors in his own experiments. The great mass of medical men firmly believe that vaccination protects against variola; and, that vaccinia and variola are ALIKE is quite certain; it is only the degree of the likeness that can be subject of dispute, for both are pyrexial pustular diseases.
Statistics of a number of years, nevertheless, show that variola is, in the aggregate, about as deadly as ever, allowing for a natural decrease of its vis by age; this cannot be controverted, so much must be conceded to the antivaccinators.
And yet, given groups of individuals are evidently protected for the time from variola by vaccination, and the more recent the vaccinia the greater the temporary protection, provided the effect of the vaccination be not too great, in which case there will be a homoeoprophylactic aggravation, and then there will not only be no protective power, but on the contrary the vaccinate will be predisposed to it, i.e., instead of a positive and a negative eliminating one another we shall have two positives to be added together.
Let us express the difference between a vaccinated and an unvaccinated individual by the algebraic quantity x. Now, what is the nature of x? Is it positive or negative? Quoad perfect health it is negative, but quoad the organismic individual it is positive, if a diseased condition can be said to be a positive one.
To begin with, it is inconceivable that x should be a CONSTANT FACTOR, which is evidently the general assumption; it must be an always lessening quantity, and x might thus be initially congruent with variola, while it may at any subsequent point be incongruent. This really expresses the sum of human experience on the question of the efficacy or inefficacy of Jennerian vaccination, though it is not apprehended; whence the cry for re-vaccination coup sur coup on the one hand, and the want of faith in vaccination on the other, both positions being readily comprehensible if the effect of vaccination be recognised as an inconstant factor.
And from these considerations it must be manifest that the protection afforded by vaccination will be different in different individuals, and diminishingly different in the same individual, and always growing less and less until it is nil. Thus x might to-day be preventively equal to variola in an endemic form, but not equal to it in epidemic form. In other words the protection afforded by x is relative and contingent. Moreover, if the vaccinosis be too great i.e., too powerfully diseasing, it not only does not protect, but must actually add fuel to the flames.
We thus appear to arrive at the conclusion that vaccination does relatively and contingently protect from small pox as a disease, but in a greater percentage. That is to say, fewer people probably get small-pox, but the absolute number of deaths is not affected, or is greater.
In pro-vaccinational and antivaccinational literature, morbility and mortality are commonly confounded together. We have no means of knowing how many people get small-pox, either absolutely or proportionately, we, only know how many die of it. Therefore all the vaccination statistics are wide of the mark except perhaps those in certain hospitals. The pro-vaccinators maintain that vaccination protects from variola because they see that, as a general rule, the vaccinated do not get small-pox. The anti- vaccinists say, “Oh! but a good many of your vaccinated persons do get small-pox nevertheless, and the mortality from small-pox is as great as ever, or greater than ever!” Both sides are honest; both are apparently dealing with facts; both are striving after truth, and collectively they expend enough human energy to enrich a nation or colonize a continent. Where then is the missing link?
While writing this an ardent bacterist, Dr. H. Thomas, of Llandudno, very kindly sends me a clipping from the Athenaeum of March 15th, 1884. It run thus: “M. PASTEUR and his fellow labourers communicated to the Academic des sciences on the 25th of February the important fact that by inoculation with virus taken from mad dogs they can render all dogs absolutely safe from the effects of rabies, in whatever way and in whatever quantity the virus may be administered.”
This is the same fact referred to by Dr. Skinner further back.
But we find no principle enunciated here by the Athenaeum: nevertheless, the results must be in obedience to the law of similars in prophylactics- homoeoprophylaxis.
Here M. Pasteur and his fellow-workers, just the same as the Jennerian vaccinators, and the anti-vaccinators -here, I say, they practically ignore the element time, and the altering nature of the protection. When people speak of “the necessity of re- vaccination, because vaccination loses its effect,” time is roughly reckoned with, but an arbitrary limit is set entirely devoid of any scientific basis.
On the other hand it has been often noticed that a healthy person gets variola soon after vaccination, which to my mind militates in no wise against a belief in the protective power of vaccination, but is to be interpreted as meaning that the vaccinial infection was more than enough; just the same as a little Aconite will make the feverishness worse.
Continuing now to let x stand for the difference between a vaccinate and a non-vaccinate, we must keep well before our minds that x represents the remaining effects of a disease-vaccinosis- and this is not a constant quantity; in an otherwise healthy person it must be continually growing less and less, and finally become extinct. Therefore, in order to determine whether vaccination protects against variola or not, we must first have the date of the vaccination in each case of varioloid or small- pox in the vaccinate. Were a considerable number of such cases tabulated we might arrive at some idea as to how long a given vaccination continues to affect the individual sufficiently for the vaccinosis to leave no room for variola, provided always that the vaccination were unipotential.