On the 27th January 1780, fifteen individuals were bit by a mad dog, and attended at Senlis by the Commissioners of the French Royal Society of Physic. Ten had received the bites on the naked flesh, and five through their clothes. Of the first ten, only five lost their lives, three of them dying of decided rabies between the 27th February and the 3d April, and the other two between the 29th February and the 18th March. Therefore, unless the opinion be adopted that the disease is caused by an infectious principle, a sort of inoculation, it would be impossible rationally to explain the cause of so many deaths from the bites of rabid animals. If, on the other hand, the idea that rabies originates from fear or nervous irritation were true, how could we account for there being such a difference between the usual consequences of the bite of a healthy dog and those of the bite of one affected with rabies? Healthy dogs are incessantly quarrelling and biting each other in the streets, yet their wounds are not followed by rabies; and if hydrophobia were referrible to nervous irritation derived from the wounded part, how does it happen that, amongst the thousands of wounded after a great battle in time of war, hydrophobia is not seen instead of tetanus or locked-jaw? But if it were yet possible to entertain a doubt of an infectious principle in hydrophobia, this possibility would be removed by the reflection that the disease may be accompanied by tetanic symptoms, and that it can be communicated to healthy animals by inoculating them with the saliva of certain other rabid animals. In short, as I have already stated, the bites of such animals arc in every point of view only an inoculation, and the same remark may be extended to the numerous instances on record in which the disease arose in the human subject as a consequence of a rabid dog or cat (not suspected to be in this state at the time) having been played with, fondled, or suffered to lick the hands or naked skin, in which there was at the moment some slight scratch, entirely forgotten or overlooked.

Indeed, many of the ancient writers not only believed in the hydrophobic virus or infectious principle, but even in its diffusion through the blood, flesh, and secretions in general. This hypothesis was professed by Bocrhaave, Swieten, and others; but in proportion as the humeral pathology lost ground, the foregoing idea was abandoned, and the opinion adopted that the infection is confined to the saliva and wounded part in which it has been inserted.

Again, the tales of some old writers would lead one to think that hydrophobia may be communicated by eating the flesh of a rabid animal. But these accounts are not entitled to much confidence, for it is certain that rabies never begins, as is stated with regard to some of the cases in question, a few hours after the application of its cause, and its early stage is never characterised by any fury or disposition to bite. And, besides, how can such relations be reconciled with the practice of the ancients, who, according to Pliny, employed the liver of a mad dog or wolf as a remedy 1 Palmarius also fed his patients for three days with the dried blood of the rabid animals without exciting the disease. The flesh of a bullock which had been bit by a mad dog and afterwards died rabid was sold to the inhabitants of Medola near Mantua, yet none of them were affected or attacked by hydrophobia. In fact, we have the following statement from Dr. Le Camus, that he had eaten the flesh of animals which died rabid, but he suffered no inconvenience from the experiment And it is stated in a letter from Dr. Valentin that certain negroes in the United States of America had no illness from eating the flesh of pigs which had died of rabies.

As for the question whether the blood is affected or infected, it is considered generally to be settled in the negative, notwithstanding the account given by L6mery of a dog which was attacked by rabies, as is said, from lapping the blood of a hydrophobic patient who had been bled. At the same time, Dupuytren, Breschet, and Magendie were never able to communicate rabies by rubbing wounds with blood taken from mad dogs; and they even on several successive occasion injected such blood into the veins of other healthy dogs, yet none of these latter animals were attacked with rabies, though they were kept for a sufficient length of time to leave no doubt upon the subject.

Now I think a point of greater practical interest than the former is whether the drinking of the milk of an animal labouring under rabies is attended with any risk of communicating the disease.

It is asserted that a peasant, his wife, children, and several other persons, were seized with hydrophobia in consequence of drinking the milk of a rabid cow, and that the husband and eldest child were saved by medical treatment, but that the wife and four of the children died. It is further stated that three or four months afterwards the maid and a neighbour, who had partaken of the milk of the same cow, also died of hydrophobia. But, in opposition to this account, we have several facts recorded by writers of great credit, and they maintain that hydrophobia cannot be communicated by the milk of a rabid animal My own impression tends in this direction likewise; for it must be borne in mind that long before an animal becomes rabid the secretion of milk would necessarily be arrested.

Neither can hydrophobia be imparted by the breath, notwithstanding the statements of some old writers. A nurse, mentioned by Dr. Vaughan, repeatedly kissed a hydrophobic infant, which she had suckled, and exposed herself incessantly to its breath, but without the least ill effects. The fear which has also been entertained of the disorder being receivable from the application of the patient's perspiration to the skin is not founded upon any authentic facts.

Now the question that we have to determine is, does the infectious principle of rabies reside in the salivary secretion or in the mucus of the trachea and bronchi? The common belief is, that, in hydrophobia, the salivary glands are considerably affected. But it has been remarked by a modern writer, that if these glands exhibit no morbid alteration during the whole course of the disorder; if they are found healthy after death; if the air-passages are the seat of inflammation; if the saliva does not constitute the frothy slaver about the lips, and if such slaver, wherewith the disease may be communicated by inoculation, is derived from the windpipe, which is inflamed, and the bronchi as well; and if it consists of a kind of mucus converted into a foam by the convulsive manner in which the patient breathes, - there is some reason for questioning whether the saliva, strictly so called, undergoes the alteration generally supposed. However, this writer is not exactly correct when he describes the frothy secretion about the mouth as being altogether composed of mucus from the windpipe, since a very great part of it is unquestionably true saliva and mucus secreted in the fauces and mouth.