milking these sources had supplied the infection, and the peculiar fermentation was distinctly shown to be microbial in origin. So-called red and blue milk, and those various hues ranging from bright lemon to orange and amber, are also now known to be directly attributable to bacterial activity.

But of even greater significance than all these bacterial dairy troubles is the risk of spreading disease which is furnished by milk contaminated with pathogenic micro-organisms.

"There can be no shadow of doubt," said the Lancet now many years ago, "that the contagia of typhoid and scarlet fever are disseminated by milk, and that boiled milk enjoys a much greater immunity from the chance of conveying disease."

This was written at a time when the study of bacteria was yet in its infancy, and before any direct experimental evidence had been obtained on the behaviour of microbes in milk or concerning the part played by them in the dissemination of disease. The writer evidently did not venture to cast further aspersions on the character of milk, or he might have included diphtheria amongst the diseases which can be spread by its means; but there is another omission which still more conclusively indicates the remote age in the history of bacterial science at which this correspondent to the Lancet wrote, and that is the absence of

all reference to the tubercle bacillus in relation to milk. At the present day hardly a bacteriological journal is published which does not contain some reference to the question of tuberculosis and milk, and the transmissibility of this disease when present in cattle to man.

As regards the dissemination of various zymotic diseases by milk, the evidence which has been collected points very conclusively to the responsible part which may be played by milk in this connection. Many instances have been cited, also, of the culpability of milk in distributing typhoid germs. A striking case which occurs to me, and which may be mentioned in passing, is one which occurred in a city in America a few years ago, in which an outbreak of this disease was traced to a dairy in which the vessels had been washed out

with typhoidal-polluted water. No less than 386 cases of typhoid declared themselves in six weeks, and of this number over 97 per cent. occurred amongst families obtaining their milk from the same dairy. A careful inspection revealed the fact that the milk-cans had been rinsed out with water from a shallow well contaminated with typhoid dejecta.

Diphtheria is also justly associated with infected milk, and if we take into consideration the now established fact that diphtheria bacilli thrive and

multiply with particular facility in milk, even more so than in ordinary broth cultures; that they have been found in air in a vital and virulent condition, and may be scattered far and wide attached to dust particles; and if we remember the numerous opportunities offered for the infection of milk by persons handling it, who either themselves are suffering from this disease or are in diphtheria surroundings -then indeed we can readily understand how milk becomes a diphtheria-carrier of the first order.

Tuberculosis in cattle, and how this disease may affect the character of dairy produce, is, as already pointed out, a subject which is attracting the attention of a large number of investigators.

The general public is perhaps hardly aware of how widespread this disease is amongst cattle, and it is only of late years that very careful inquiries have elicited the fact that it is not only very extensively distributed, but may be present in animals to all outward appearance in perfect health.

In Germany it was asserted a few years ago that every fifth cow was tuberculous, and even this was regarded as a moderate estimate. The distinguished Danish pathologist, Professor Bang, is responsible for the announcement that during the years 1891-3 17.7 per cent. of the animals slaughtered in Copenhagen were infected with

tuberculosis.

In Paris we have been told that, of every thirteen samples of milk sold, one was infected with tubercle bacilli, whilst in Washington one in every nineteen samples of milk was stated to be similarly tainted.

The existence of tubercular disease in cows, and its transmission to other animals fed with their milk, has been brought out in a striking manner in investigations published by the Massachusetts Society for the Promotion of Agriculture. In one case as many as over 33 per cent. of the calves fed with milk from tuberculous tuberculous cows succumbed to the same disease. According to Hirschberger, 10 per cent. of the cows living in the neighbourhood of towns where the conditions. of their environment are not generally the most satisfactory or conducive to health suffer from tuberculosis, and 50 per cent. of these animals yield milk containing tubercle bacilli.

The demand which is being made by municipal authorities to be invested with the power of inspecting the country farms from whence their cities are supplied with milk and other argricultural produce could not have received stronger support than was recently supplied by a case tried in Edinburgh, and as this is only a sample of what is doubtless a daily, although undetected occurrence in many municipalities, it will not be

out of place to quote the following from the published report of the proceedings :

"A cow was brought into the city for sale as food, and the evidence showed it to be in the last stages of tubercular disease. 'Its head was hanging down; it breathed with difficulty, and it had frequent fits of coughing; while its udder was swollen with the disease.' All the organs were diseased, and the milk teemed with bacilli. Yet, it seemed, the milk from this animal had been regularly sent into Edinburgh for sale. In face of facts like these, it is difficult to see on what grounds the claim of towns to inspect country dairies doing a town business can be resisted. At least the towns should have the power to refuse admission to milk from sources not open to inspection. It is not enough for the county authorities to say that they inspect the dairies in their own areas. In this case the condition of the animal was only found out when it was brought into the town to be sold for food."

Further comment is unnecessary!

Some German investigators have discovered the interesting fact that the centrifugal method of separating milk not only has a remarkable effect upon its bacterial contents, but also upon tubercle bacilli when present. On examining the so-called "separator slime," it is found to contain not only large quantities of solid matters, but also masses of bacteria which have been thrown out during the operation. This method of treating milk has,