A very striking life in its lessons for the serious student of medical
problems is that of Edward Jenner, who first demonstrated to the world
that a simple attack of mild, never fatal, cowpox, deliberately
acquired, might serve as a protective agent against the deadly
smallpox, which before that time raged so violently all over the
civilized world. His successful solution of this problem has probably
saved more lives and suffering than any other single accomplishment in
the whole history of medicine. While this fact is apparently not
generally appreciated, Jenner's discovery did not come by mere chance,
but was the result of his genius for original investigation, which led
him to make many other valuable observations covering nearly the whole
range of medicine; nor indeed was his activity limited to medicine
alone, but extended itself to many of the allied sciences, and even to
scientific departments quite beyond the domain of medicine.
In medicine we owe to Jenner the first hint of the possible connection
between rheumatism and heart disease. He pointed out, at a discussion
in a little English medical society, how often affections of the heart
occurred in those who had suffered from previous attacks of
rheumatism. He was among the first, perhaps the very first, to hint at
the pathological basis of angina pectoris. While Heberden's name is
usually connected with this discovery, there seems good reason to
think that already Jenner had independently noted and called attention
to the frequency with which {90} degenerative affections of the
arteries within the heart muscle itself were to be found where during
life heart-pang had been a prominent and annoying symptom.
Besides these important advances in medicine made by him, and his
great discovery of the identity of cowpox and smallpox, Dr. Jenner was
an interesting observer of phenomena in all the biological sciences,
and in geology and palaeontology. He was a great friend of Dr. John
Hunter, who frequently suggested to him the making of such experiments
and observations as were more likely to succeed in the country than in
the city, and one cannot help but be struck with the determination
evinced all his life to take nothing on authority, but to test
everything by actual observation, and above all not to theorize where
he did not have the actual data necessary for assured conclusions; and
even where he thought he had them, his wonderful faculty for waiting
until they had properly matured, and their true significance had
become evident, stamped him for all time as a model for scientific
investigators.
Undoubtedly Jenner's greatest work was that of determining the value
of vaccination. His patient investigation of this subject, the
thorough conservatism with which he guarded himself from publishing
his conclusions until he had tested them in every way, the absence of
that haste to rush into print so characteristic of most present-day
medical investigators, and which is the cause of so much
disappointment in modern medicine, all distinguished this country
physician as one of the greatest investigating geniuses that medicine
has produced. His life is a mirror for the medical student and the
investigating practitioner of medicine. His discovery was so complete
when he finally announced it that but very little has been added to it
since. His invention came from his mind as Minerva from the brain {91}
of Jove fully armed for the conflict that was sure to come. In this
Jenner resembled very much Laennec and the other investigating
geniuses in medicine. As a matter of fact only one improvement has
been made in the preparation of vaccine material since Jenner's time,
and that is the incorporation of glycerin in very recent years, which
gradually destroys any micro-organisms that may be present, leaving
the vaccine virus itself unimpaired in its efficacy, though without
the possibility of inflicting those secondary infections which for so
long cast a shadow on vaccination.
Dr. Edward Jenner was the third son of an Anglican clergyman, his
mother being the daughter of a clergyman who had been at one time
prebend in the cathedral of Bristol. The family held considerable
property in Gloucestershire. He received his early education at
Wotton-under-Edge and later at Cirencester, the old Roman town in
Gloucestershire. While he acquired a good working knowledge of the
classics, from his earliest years he was interested in natural
history. Before he was nine he made a collection of the nests of the
dormouse. The hours that other boys spent at play he devoted to
searching for fossils or other interesting natural curiosities.
After his preliminary education had been finished he was apprenticed
to Mr. Ludlow, an eminent surgeon at Bristol, and after two years here
he went to London, where he had the privilege of residing as a
favorite pupil in the family of John Hunter for two years. At this
time Jenner was in his twenty-first year, John Hunter in his
forty-second. Hunter was not then a public lecturer, but he had been
for two years surgeon to St. George's Hospital, and for nearly five
years had been engaged in studying the habits and structure of animals
in a menagerie and laboratory which he had established at Brompton.
The inspiration of Hunter's original {92} genius meant much for young
Jenner. He learned not only to respect the teacher but to love the
man. In Hunter's unquenchable desire for knowledge and love of truth
there was something very congenial to the spirit of Jenner, who was
himself, above all things, an inquirer.
After completing his two years of work with Hunter he still remained
intimately associated with him by letter. Though later in life
Jenner's correspondence became very voluminous, these letters from
Hunter were always very carefully preserved in a special cover, and
they serve to show how stimulating to the young man must have been
Hunter's virile enthusiasm for truth as it could be deduced by
observation and experiment.
It was to Hunter that Jenner once wrote that he had heard it said in
Gloucestershire that the dairy workers who suffered from a certain
disease caught from the udders of cows and called cowpox were
protected thereafter from attacks of smallpox. He added that this
tradition interested him very much and that he intended to think about
it. "Don't think," wrote Hunter to him, in return; "make observations,
investigate for yourself the truth of the tradition." Jenner did so,
and the result is now known to all.
These letters from Hunter contained many other interesting
suggestions. For instance, it was under Hunter's direction that Jenner
succeeded in finding out that in hibernating animals the temperature
is very much reduced and the respirations are very slow, while the
rate and force of the pulse are often so much diminished as to be
scarcely more than noticeable at the extremities. Between Hunter and
Jenner it had already been discovered that the sap in trees will not
freeze at temperatures much lower than that at which the same fluid
freezes when withdrawn from the tree, and the same thing seemed to be
true with regard to {93} the blood of hibernating animals. He learned
that notwithstanding the low temperature to which it is reduced the
animals are not affected particularly by the cold, though their store
of fat is consumed and they awake very hungry in the spring-time.
Besides hibernation Jenner also investigated the habits of the cuckoo,
that crux of the biologist which insists on foisting its eggs upon
other birds and allowing its orphan young to be brought up in alien
nests, while the real young of the deceived foster-parents are often
pushed out of their nests by this burly intruder which grows so fast
and strong. It is needless to say, this subject interested John Hunter
very much and there are a number of letters which passed between them
on the subject.
It must not be supposed, however, that young Jenner was entirely
occupied with his scientific work to the exclusion of social life and
recreation. He was one of the best-known men of the county, and was
looked upon as a genial companion from whom might be expected on
almost any occasion pleasant jests and epigrams, not too biting, with
regard to friends and acquaintances. Some of these have been preserved
and we quote several of them as indicative of his special vein of
humor.