In July 1906 attention was drawn to the fact that a large number of tinned foods returned from the South African campaign were exposed for sale on the home markets. The majority of these foods were known to have been from five to seven years in tins, and the possession of this material afforded a rare opportunity for investigating the question of metallic contamination, and for determining how far such contamination was deleterious to the public health.

Ankylostomiasis was first discovered in men working in Cornish mines in October, 1902 (this Journal, Vol. III. p. 95), though there had been many cases of illness clearly referable to this cause for some eight years previously. The number of men who were too ill to do their ordinary work was greater about two years before the cause of “Dolcoath anaemia” was identified. These men had either stopped at home or had been employed on the surface instead of underground: in this way they had avoided further infections, and in many cases had progressed towards a spontaneous cure. At the time therefore of our first enquiry the number of sick men was less than it had been. Anaemic miners were, however, still very numerous and, without anything like an exhaustive search among the 750 underground hands at Dolcoath mine, we found 14 men with less than 50 p.c. haemoglobin and 19 more with less than 75 p.c. The general pallor prevalent among the men on looking at a shift as a whole was very striking, and complaints of shortness of breath on climbing the ladders were frequent. The disease, in short, was at that time a meterial hindrance in carrying on the work of the mine.

That cellular elements are found normally in milk has been known for many years, but it is only comparatively recently that any importance from a public health point of view has been attached to their presence. These cellular elements being usually regarded as leucocytes or pus cells, it is natural that their occurrence in milk should be looked on as indicative of an inflammatory process in the udder of the cow or cows from which the milk was obtained. The first observers to make any attempt to arrive at the numbers of these cells in milk seem to be Stokes and Wegefarth (1) in 1897. Their method, however, was very crude, and is not suited for making a true enumeration. Stewart (2) and Slack (3) followed with a very similar method, except that special tubes were used for obtaining the deposit. This “smeared sediment method” as it is called, is, however, capable of great inexactitude. Later observers have, by the use of ordinary blood counters, made the counting of the cells in milk a scientific measurement of reasonable accuracy. To Doane and Buckley (4) belongs the credit for the first published use of such a method. Savage (5) however has made the process still more accurate by first diluting the milk before centrifugalisation, and also by counting all over the field of the blood chamber, two innovations which are of very great importance, as has been borne out by our investigations. Error is easily introduced if counting is confined to the ruled divisions of the counter. Recently, Trommsdorff 6 has used a methodbased on the measurement of the deposit obtained on rotation in agraduated tube, and this method, probably on account of its ease and speed, has found much favour in Germany. It has been severely criticised by several investigators, such as Schuppius 7 and one of us 8. Riihm 9 and some others believe that it is useful if used as a routine control method. We are of opinion that it might be used in such away as an “indicator,” but for the purposes of public health control it isquite hopeless.

At the commencement of this paper it was pointed out that anthrax has been associated with the manipulation of hair and other raw animal materials for at least a century and a half, but that it has only been studies from an industrial point of view during the last 30 years, with the result that in 1895 cases of anthrax, occurring in workshops and factories, became notifiable. From that time to the end of 1907, over 500 cases have been brought to the notice of the Home Office. Beside these cases of industrial anthrax many others arise, chiefly from contact with animals or animal carcases affected with anthrax; these are not notifiable in this country.

The proportion of industrial to non-industrial cases of anthrax is about 4 to 3.

An analysis of cases of anthrax notified between 1898 and 1907 shows:

(1) A progressive increase in the number of cases in the woollen and worsted-industries, probably due to the increased use of dangerous classes of wool.

(2) A progressive increase in the rate of mortality, due to the larger number of internal cases among manipulators of wool.

(3) A lower rate of mortality among workers on horsehair and bristles than in other industries.

(4) A high rate of mortality in the group of miscellaneous industries in which anthrax is not usually suspected, the diagnosis being then made too late for effective treatment.

In order to make an early diagnosis it is essential for anthrax to be suspected from the nature of the employment.

Among bristle and horsehair workers:

(1) Anthrax is more fatal to the women than to the men.

(2) The occupational risk is greater for the men than for the women, because the former are more often employed in the earlier, more dangerous manipulations.

(3) The occupational risk is greater and the mortality higher among the manipulators of horsehair than in brushmaking.

(4) Horsehair is from 8 to 10 times as likely to give risk to cases of anthrax as are bristles, and the risk of infection is greatest from Chinese, Russian and Siberian raw materials; this is confirmed by actual experience not only in this country but abroad.

(5) The risk to workers on horsehair is greater than the risk to workers on wool.

The nature of the lesion varies considerably with the industry, inhalation of spores being uncommon in any but the woollen industry, though internal cases undoubtedly occur among horsehair manipulators. This is not surprising as many of the processes in these industries are similar.

The position of the pustule varies slightly with the occupation; for example, pustules on the neck are most frequent among hide and skin workers, due to the frequent carrying of skins on the shoulder. Malignant pustule is most common on the exposed parts, and to the latter those less frequently washed, as the neck and face. The infection is in most cases by the nails, which harbour the dust containing anthrax spores.

In agricultural cases lesions on the upper extremity are most common.

The mortality varies with the situation. Difficulty of operation, frequent absence of the diagnostic signs of local necrosis, looseness of the cellular tissues increase the mortality.

In all countries except Great Britain agricultural anthrax is the most common, and consequently there is a close relation between the number of cases of human and animal anthrax.

Variations in the prevalence and mortality of anthrax among human beings occur in different countries, and may to some extent be accounted for by natural constitution and environment.

There has been a progressive increase of cases in Italy, but a decrease of the death-rate, roughly corresponding to the introduction of Sclavo's serum treatment.

French statistics, as do the English, emphasize the greater risk to horsehair workers, though the risk and mortality in Great Britain compare very favourably with those in Franch, and still more so with those in Germany.

The danger of infection from anthrax in the manipulations of animal hair and bristles depends on the origin, king and cleanliness of the materials, and the processes they have to undergo.

Bristles as imported vary immensely, some being well cleansed and prepared, others in an extremely dirty state, but they are always in a far more prepared state than the horsehair.

The long tail horsehair, being more valuable, is better cleansed and less likely to cause infection than the shorter mane horsehair.

Cases of anthrax occur in practically all the processes to which hair is subjected from its time of arrival even to the finished products. Further, incidence is greatest among workers in short hair as brush-makers, and in the earlier processes, i.e. when the hair is in a less prepared state.

Infection may be carried in clothes or nails to people outside by workers.

Anthrax spores may retain their vitality for years on hair and other materials.

The dangerous classes of hair are very generally used. This is not so in the woollen and worsted trades.

Anthrax is common among animals all over Europe and Asia, and in most countries there is an increased incidence during the hot summer months. It is probable that in certain districts special conditions exist which make them permanent centres of anthrax infection. Here too hides and hair from contact with the soil may possibly become infected without the animals actually contracting anthrax.

In previous papers Professor Symmers and myself have called attention to the presence of agglutinins for the typhoid bacillus, the colon bacillus, and a bacillus of the alcaligenes class in the blood serum of patients suffering from cerebro-spinal fever from whose lumbar puncture fluid and in some cases from whose blood the Micrococcus intracellularis meningitidis (Weichselbaum) had been cultivated.

In the Milroy Lectures of this year, Professor Hewlett stated:—“There is some evidence to show that the germicidal power of emulsified disinfectants is greater than can be accounted for by the activity of the active constituent and theoretically seems likely, but we want some reliable experimental work in confirmation. It is ture that Chick and Martin have compared the germicidal value of higher tar acids emulsified in water and dissolved in alcohol, their results showing that the emulsified form was much more active; but the reliability of this work is vitiated by the fact that they have entirely failed to take into account the influence of alcohol in decreasing germicidal activity; for example in the case of phenol, which I dealt with in my last lecture”.