_Scarlet Fever._ Here again the evidence is not complete, chiefly owing to the fact that no specific organism of scarlet fever has yet been discovered. Many cases have, however, illustrated the undeniable conveyance of the disease by milk. Even before 1881 a number of milk epidemics of scarlet fever had been traced out. In 1882 these were further added to by Mr. W. H. Power's report concerning a series of cases in Central London. That report was remarkable for the introduction of a new feature, viz., the evidence produced in favour of the infection of milk from some disease of the cow. The Medical Department of the Local Government Board from that time took up a position of suspended judgment concerning the belief hitherto credited that milk could only be infected by _human_ scarlet fever. In 1886 there was a remarkable epidemic in Marylebone, and the theory was suggested by Dr. Klein and Mr. Power that the cow from which the milk was derived suffered from scarlet fever. Into the extensive controversy which raged round "the Hendon disease," as it was called, affecting the cows supplying the Marylebone milk, we cannot here enter. It will be sufficient to say that a long discussion took place as to whether or not this Hendon disease was or was not scarlet fever. The difficulty of course largely arose from the fact before mentioned that we do not at present know the specific micro-organism of scarlet fever. The Agricultural Department supported the view of Professor Crookshank that the cow disease at Hendon was _cow-pox_, and Professor Axe further pointed out that there was evidence of the Hendon milk having been contaminated with human scarlet fever. Whichever conclusion was adopted, all were agreed upon one point, viz., that the disease had been conveyed from Hendon to persons in Marylebone by means of the milk. Mr. Ernest Hart in 1897 published a very large number of records of scarlatinal milk infection from all parts of the country, and though the cause of the disease is obscure, there is now no doubt that it may be and is conveyed by means of milk. _Other Diseases Conveyed by Milk._ In addition to the above, there are other diseases spread by means of polluted milk. From time to time exceptional cases have occurred in which a disease like anthrax has been spread by this means. But it is not to such rare cases that we refer. There are two very common diseases in which milk has been proved to play a not inconsiderable part, viz., _thrush_ and _diarrhœa_.