About the latter end of February, 1798, William Haynes and Thomas Virgoe, having to wash a Mare with sore heels, were infected with Grease, and described their sensations as much the same as when they were inoculated with Smallpox. Their infection proved that if Grease was good against Smallpox, Smallpox was not good against Grease. Haynes was employed as a milker, and Pox broke out among his master's Cows about ten days after he had first assisted in washing the Mare's heels.

XVIII. JOHN BAKER, five years old.

Inoculated, 16th March, 1798, with matter taken from a pustule on the hand of the aforesaid Thomas Virgoe poisoned with Grease from the Mare's heels. "He became ill on the sixth day with symptoms similar to those excited by Cowpox, and on the eighth was free from indisposition."

On this case of Horsegrease inoculation, Jenner observed

We have seen that the virus from the Horse is not to be relied upon as rendering the system secure from variolous infection, but that the matter produced by it on the nipple of the Cow is perfectly so. Whether the virus passing from the Horse through the human constitution, as in the present instance, will produce a similar effect remains to be decided. This would have been effected, but the boy was rendered unfit for Smallpox Inoculation from having felt the effects of a contagious fever in a work-house soon after this experiment was made.

Mark the assumption, " The virus from the Horse is not to be relied upon as rendering the system secure from variolous infection, but the matter produced by it on the nipples of the Cow is perfectly so!" Such was Jenner's method of induction! How could he leave the question undecided? Why not have waited until little Baker recovered from his fever? or why not have inoculated another work-house child with Horsegrease? The true sons of science do not rush into print in such shameless deshabille.

XIX.-WILLIAM SUMMERS, aged five and a half. Inoculated 16th March, 1798, from the nipple of one of the Cows infected with Horsegrease by Haynes. Subsequently inoculated with Smallpox without effect.

XX.-WILLIAM PEAD, aged eight.

Inoculated, 28th March, from Summers. Subsequently inoculated with Smallpox without effect.

XXI.—HANNAH EXCELL, aged seven,

And several children and adults were inoculated from the arm of Pead on 5th April. "The greater part of them sickened on the sixth day, and were well on the seventh; but in three of the number a secondary indisposition arose in consequence of an extensive erysipelatous inflammation which appeared on the inoculated arms. By the application of mercurial ointment to the inflamed parts (a treatment recommended under similar circumstances in the inoculated Smallpox) the complaint subsided without giving much trouble."

Excell was inoculated in three places on her arm. 'This," said Jenner, "was not done intentionally, but from the accidental touch of the lancet, one puncture being always sufficient." The resulting pustules so much resembled those arising from inoculation with Smallpox, "that an experienced inoculator would scarcely have discovered a shade of difference."

XXII.-FOUR CHILDREN.

On 12th April virus was taken from Hannah Excell and inserted in the arms of—

ROBERT F. JENNER, aged 11 months,

JOHN MARKLOVE,

inflamed, and Jenner fearing erysipelas, as in the preced

ing cases, applied a caustic of soap and quick-lime to Marklove and James, " which," he says, " effectually answered my intention in preventing erysipelas." The disease was suffered to take its course in Pead, and no erysipelas appeared.

XXIII. JOHN BARGE, aged seven.

Inoculated from Mary Pead, and successfully. Was subsequently inoculated with Smallpox without effect.

"These experiments," said Jenner, "afforded me much satisfaction; they proved that the matter in passing from one human subject to another, through five gradations, lost none of its original properties, John Barge being the fifth who received the infection successively from Wm. Summers, the boy to whom it was communicated from the Cow."

These are Jenner's Cases. In them we have his Masterpiece of Medical Induction"-the fruit of thirty years of incessant thought, of watching, and of experiment! Let us carefully observe the dates. Until 1796, when he operated on Phipps, he never made an experiment in Horsegrease Cowpox Inoculation; and not until the middle of March, 1798, a few weeks before going to press with the Inquiry, did he repeat the experiment; and though his later cases were complicated with erysipelas, he did not stay to dispose of the difficulty and alarm thereby excited. He got together his scratch lot of Cases, as if under some over-mastering compulsion, and consigned the concern, crude and incomplete, to the public. By-and-by the hasty performance came to be spoken of as the result of thirty years of incessant thought, of patient research, and of unwearied labour. It is unnecessary to argue the matter. Whilst there is nothing too great for the credulity of those who are in the disposition of belief, yet facts are facts, and there is the stone-wall of the Inquiry with its authentic details whereon to crack the skulls of romancers. In Jenner's story as recited to the vulgar, we have the advantage of

witnessing the development of myth in the light of our own age under our own eyes.

Taking Jenner's Inquiry at the utmost, What was it? A suggestion to substitute Horsegrease Cowpox for Smallpox in inoculation. That was all. Beyond this there was no point of novelty. Some have credited Jenner with originating the transfer of virus from arm to arm; but in this respect he followed the example of many variolators. There was a mild form of Smallpox occasionally prevalent in London called "pearly pox," and Dr. Adams and others kept it going from patient to patient; and the virus from the body of a healthy varioÎated child was in constant request by timid folk, who fancied the virulence of the original infection might thereby be abated in transmission.

So much for Jenner's data. Now for a word or two as to the speculation that invested his prescription.

He considered that some of the diseases which afflict men are derived from their domestication of animals, and that thus several diseases might have a common origin. "For example," he asked, "Is it difficult to imagine that measles, scarlet fever, and ulcerous sore throat with a spotted skin, have all sprung from the same source?"

About the imagination, there might be little difficulty: the difficulty lay in the production of proof that any disease in man was derived from disease in animals, and that disease so derived was variously manifested. Jenner wished to have it believed that a variety of Cowpox was generated from Horsegrease, which Cowpox was the source of Smallpox. He adduced no evidence, however, to connect outbreaks of Smallpox with Cowpox; nor did he ever suggest that dairymaids caught Smallpox from Cows, or farriers from Horses. His identification of Horsegrease Cowpox with Smallpox was the resemblance of their pustules, and on the ground of this resemblance he affirmed the equivalence of the diseases. Thus in describing his first inoculation of Cowpox, that of Phipps from the hand of Sarah Nelmes on the 14th of May, 1796, he wrote

The appearance of the incisions in their progress to a state of maturation was much the same as when produced in a similar manner by variolous matter. This appearance was in a great measure new to me, and I ever shall recollect the pleasing sensations it excited; as, from its similarity to the pustule produced by variolous inoculation, it incontestably pointed out the close connection between the two diseases, and almost anticipated the result of my future experiments. (P. 30.)

The similarity of the Cowpox and Smallpox pustules incontestably pointed out the close connection between the two diseases! The observation and the conclusion are worth notice, being characteristic of Jenner's loose and illogical mind. He was familiar with Tartar Emetic, and he might have observed that it produced pustules on the skin exactly like those of Cowpox and Smallpox; wherefore would it have been fair to argue that the pustules being alike, their causes were incontestably identical? Dr. Hamernik of Prague observes

Some years ago the theory was brought forward, under the auspices of the great alchemistical artist, Hufeland, that Vaccination from Tartar Emetic pustules was a perfect substitute for Vaccination with Cowpox, and had the same beneficent effect. With this I fully agree; and I remark further, that if Tartar Emetic pustulation is produced in Cows and Calves, and vaccine matter is then taken from them, such Vaccination is also perfectly harmless. The most convincing proof of the beneficent and identical action of such Vaccination with that of Cowpox, is furnished by the fact that it presents pustules similar in size and form, therefore, necessarily of identical value.*

Having identified Horsegrease Cowpox with Smallpox, by reason of similarity of pustules, he went on to assert that such Horsegrease Cowpox was equivalent to Smallpox for inoculation, and was attended with the like prophylaxy, saying—

What renders the Cowpox virus so extremely singular is, that the person affected with it is forever after secure from the infection of the Smallpox; neither exposure to the variolous effluvia, nor the insertion of the matter into the skin producing this distemper. (P. 7.) It is curious also to observe, that the virus, which, with respect to its effects, is undetermined and uncertain previously to its

Remarks on Certain Medical Principles. London, 1882.