We may ask then, which of these two sets of premises, the cowhouse and yard, or the premises where the milk was sold, furnished the contagion of the milk? To take the cow-yard first, there were present as possible sources of Typhoid effluvia the foul receiver in the centre of the open yard, and the foul water tank over the cottage. I think we may absolve the latter at once, inasmuch as it is improbable that water would have been added to the milk here while there was plenty at the place of business whither the milk was to be carried. With respect to the foul receiver in the yard, I should place little value on any objection to it as a probable source of contagion on the mere ground of offensive effluvia not being noticed, so long as it could be shown on independent grounds that Typhoid fever had actually been contracted by any person or number of persons from exposure to its emanations, or that it was probable that the milk had been sufficiently exposed to the chance of absorbing the contagion proceeding from it. It seems to me that any emanations from the gully would, before reaching the cowhouse, have been too diluted to produce mischief in this way; while it is understood that the only other possible exposure it could have, would have been during the carriage of the milk through the open air near it. Was there, then, any independent evidence of the gully or receiver actually giving off Typhoid contagion into the atmosphere of the yard? It was a yard in which a good deal of business was carried on. Horses were stabled there, vans were washed near the gully, etc. As a fact, people employed about this yard were attacked with fever. Thus, 1st, one of the earliest, if not the very earliest case, happened in the person of a boy who was a "useful" boy about both premises-in the stables, and at the cowhouse and yard. He was so ill on July 3d that he was sent home to his mother, at Finchley, where he died of Typhoid on July 25th. 2nd. The dairyman himself, who personally milked and managed the cows, spending much of his time in the yard, was attacked early-namely, on July 9th. 3rd. The young woman at the cottage in the yard was attacked the very same day. 4th. A man who worked in the yard habitually, chiefly about the stables there and on the business premises, washing vans in the yard, etc., but who had nothing to do with the cows or dairy business, was attacked with fever early-viz.: on July 7th. 5th. Another young man, similarly occupied, was attacked on August 10th. 6th, and lastly, a cowman who came newly to work at the yard, and to take the place of the master, who was ill, in milking and managing the cows, about the beginning of August, was taken ill with Typhoid on August 27th. But in none of these cases was the certainty or probability of the dairy milk having been taken excluded. It cannot be asserted with certainty that they got their fever from a contagion evolved into the atmosphere at the cow-yard. In the first instance the boy lived on the business promises, and had his meals there, including breakfast and tea. In the second case, the same observation holds--good. In the third case, the girl had certainly taken the milk habitually up to a period within that of the incubation of Typhoid. In the fourth instance the man told me that he occasionally took his meals at the coffee house, or his tea at his mother's house, both supplied from the dairy. In the fifth case the young man habitually took his meals at the above-named coffee shop, and also sometimes carried out the milk. The sixth case alone can be supposed to have probably originated in the effluvia of the yard. This was the cowman, who boasted that he always got his milk pure, for that he drank half a pint every morning early while milking the cows, and that what he used at home with his family was taken from the cowhouse direct, in a bottle. I may observe here, that in this case the disease was confined to himself, no one else of his family or in the house getting Typhoid. But, then, as he also carried out milk from the dairy, he had the opportunity of quenching his thirst from the cans, whether he availed himself of it or not. He says he never drank any water on either of the premises, as "he does not like water." Throughout my inquiry I have met with no other case of Typhoid among men engaged at the yard, than those I have mentioned. It appears therefore to me that the evidence of Typhoid emanations into the atmosphere of the yard fails to be satisfactory.

This being so, we fall back upon the business premises. Here I found two possible sources of Typhoid contagion, viz, the offensive emanations from the stable drains and the underground water-tank which supplied the pump. The evidence of mischief from the former is as deficient as it was in the case of the emanations in the cow-yard; none of the men exposed to them having had fever except those who had been in the way of drinking the milk. And there is this additional fact, that the family most constantly and throughly exposed to these emanations escaped-namely, that of the horse-keeper, who actually lived over the stable, and the staircase leading to whose rooms was erected over a closet (not supplied with water) used by the workmen on the prenises.

It will be observed that, step by step, my inquiry has become narrowed by the process of exclusion-the only one as it appears to me, applicable in such a investigation as this. And so I have arrived at the underground tank. About this for some weeks I could learn nothing but that it was a wooden tank, constructed sixteen years ago, of three inch pine, bound with iron, and puddled at the bottom with about nine inches of clay. Awaiting the time when the tank could be opened for inspection, I forwarded samples of the water for analysis to Dr. Bernays. I did not expect much to come of this, since the outbreak was then nearly over, and an analysis made in September of water which was daily undergoing replenishment would probably give very different results from an analysis made in June or July, when it might have been somehow contaminated; and the result of the analysis confirmed my expectation. It was in all respects similar to the results of analysis of the New River Company's water, published by Dr. Letheby and by the Registrar-General-that is to say, it exhibited no special character that would indicate an unusual departure from the average purity of that water.