COMPARATIVE MERITS OF VACCINATION. 595 
private practitioners would, as a rule, be found behind the 
public work ; but in regard to the arrangements most conduc¬ 
tive to the success of vaccination, private practitioners must 
necessarily stand at a disadvantage/* While these public 
vaccinators have the advantage of a sufficiency of subjects 
wherewith to carry on arm-to-arm vaccination, they have 
the disadvantage that they know nothing of the parentage of 
the majority of the vaccinifers, and can judge of their 
suitableness merely from the looks of the mothers and the 
appearance of the children and of the vesicles. It is just the 
reverse with private practitioners. Dr. Seaton, then, is carried 
away with the single idea, arm-to-arm vaccination carefully 
conducted is perfect, and is the only perfect form of vaccina¬ 
tion. He nevertheless, like other instructors in the subject, 
gives certain directions for the renewal of the vaccine if it 
shows certain improper qualities. The seed is to be always 
the same, but the soil is to be changed. Vaccine removed 
from the cow more than eighty years ago by Jenner has been 
transmitted continuouslv from that time through human 
beings, sometimes through children of decidedly unhealthy 
parentage, sometimes through those in imperfect health, 
sometimes after purulent transformation has affected the 
lymph; and yet this fluid is to be considered purified, “ due 
and effectively 5 * protective, by being now transmitted with 
care through properly-selected healthy children. 
If vaccine lymph, a most delicate organic fluid, has once 
been allowed to undergo pathological changes in the vesicles 
has been permitted, for example, to remain in the vesicle till, 
the ninth day, or even later, after vaccination, when suppura¬ 
tion has commenced to alter its composition, can it it be 
supposed that it has undergone no deterioration? And if 
such lymph is used for vaccination,is it reasonable to conceive 
that the passage of this fluid through a child’s body is 
sufficient to restore its purity, and to supply any protective 
power it may have lost ? It is generally admitted that vac¬ 
cination has been performed very carelessly in this country 
till within the last few years, that vaccine has been removed 
from vesicles undergoing suppurative changes and used 
for vaccination, that vaccination has been performed with 
lymph from imperfectly or improperly developed vesicles, and 
yet it is affirmed that if such lymph be carefully employed, 
hereafter it will produce results identical with those of the 
true virus, will be equally protective with the original cowpox. 
According to this view, the system of a child is made to serve 
the part, not only of a searching filter, but of a reproducing 
and restoring spring. If vaccination has been performed in 
