According to Dr. O'Donovan, this is the largest problem of preventive medicine that has yet arisen from any manufacturing process. That preventive measures are successful in coping with the problem is shown by the records of certain British factories, especially those that are nationally operated.

In the list of cases given by Dr. Legge there are two factories that furnished no less than 81 cases out of the total of 181 and 24 of the 52 deaths, the others being distributed among 23 factories. We do not know the numbers employed in these places, but we are told by Dr. Moore that the two factories in question do not employ more persons than several of the others and that any visitor to them can see at once why their rate of poisoning should be so heavy. In contrast to these are a shell-filling works, reported by Dr. Sugden, with 9,000 to 10,000 men and women, and an amatol plant with 2,500, and only one case of toxic jaundice. Fleet Surgeon Munday says that in four admiralty factories with 5,000 workers there has been not only no death from TNT poisoning but no record of any person suffering from constitutional effects of the poison to such an extent as to disable him or her from work.

Munday says that the director general of the naval medical service laid it down that the Admiralty should be a model employer of labor, setting an example to all other employers in safeguarding the lives and health of the employees. No crowded rooms are allowed, no piecework, no closing of windows which should be open, no eating in work rooms, and a strict shop discipline is enforced which makes it possible to insure a high degree of personal cleanliness. There is meticulous care in the removal of fumes at the place of origin, there is a thorough system of alternation of work, medical examination is conducted once a week, and suspension from work can be ordered at the first appearance of symptoms. But the chief point emphasized by Munday is the scrupulous cleanliness of the premises, the absence of dust, of spilling and smearing over floors and benches and over the outside of shells, and the absence of staining on the workers' hands as shown when the gloves are removed for inspection. The employees are warned of the dangers by printed placards and by personal instruction.

Dr. Munday concludes: "If then a marked reduction of the number of deaths and of the incidence of cases in other factories is to be achieved, I submit that this must be accomplished by better discipline and greater cleanliness of workshops and workpeople."

MINOR TNT POISONING.

Dr. Moore emphasizes the importance of the subject under discussion on account of "the large loss of labor at a period of stress in

the country. In several factories concerned in the manipulation of high explosives the degree of absenteeism is very high, and the greatest factor in the production of this is this so-called 'minor' TNT illness. Therefore, from the national standpoint, minor illnesses due to TNT poisoning ought not to be left out of account." Cases of poisoning are not notifiable unless associated with the symptom of jaundice, but it is believed by Dr. Legge that "for every case of toxic jaundice there are at least 30 persons affected in minor degree, necessitating absence from work."

MINERS' CONSUMPTION IN SOUTHWESTERN MISSOURI.

The United States Public Health Service has made an investigation of miners' consumption, based on a study of 433 cases of the disease among zinc miners in southwestern Missouri. In the report 1 just issued it is stated that miners' consumption has been recognized for a number of years as the most important health hazard of the metal-mining industry, and as one probably widespread throughout all mining districts, but until this investigation it had never been the subject of State or Federal inquiry in this country. In this connection attention is directed to investigations in foreign countries, and particular reference is made to the report of the miners' phthisis committee of the Union of South Africa, which was noted in the MONTHLY REVIEW for January, 1917 (pp. 102 to 105). It is explained in the report under review that the zinc ore is found embedded in flint, which lies in horizontal layers or sheets, the mining operations such as drilling, blasting, etc., therefore being carried on in flint, "an exceedingly hard rock with a silica content of over 95 per cent. This flint forms a very fine, hard, sharp, and insoluble dust, which permeates the underground atmosphere to a varying extent, and which, naturally, is extremely irritating to the Jungs when inhaled, causing the condition known as miners' consumption." It appears that the chief symptom is dyspnea (on exertion), which becomes aggravated, causing gradually a falling off in the amount of work done; loss of weight is also a constant symptom. This dyspnea is associated with pains in the chest and diminished expansion. "While slaty blue sputum, when present, is diagnostic, yet the physical examination of the patient is in itself insufficient without a knowledge and consideration of the occupation." It is pointed out in passing that miners' consumption may be tuber

1 United States. Public Health Service. Miners' Consumption, a study of 433 cases of the disease among zinc miners in southwestern Missouri, by A. J. Lanza, with a chapter on Roentgen-ray findings in miners' consumption, by Dr. Samuel B. Childs. Public Health Bulletin No. 85. Washington, 1917. 40 pp.

culous or nontuberculous, according as tubercle bacilli may or may not be found in the sputum.

In this investigation 720 miners were examined, 433 being affected with miners' consumption, 103 of these also have tubercle bacilli in their sputum. For convenience these 433 are divided into three stages: (1) those characterized by little or no disability, with slight or moderate dyspnea on exertion; (2) those showing noticeable disability with moderate or moderately severe dyspnea; and (3) those showing total, or at least marked, disability with severe or urgent dyspnea. In summarizing the results of the examination of 120 men in the first group, 142 in the second group, and 68 in the third group, all without tuberculous infection, attention is called to the fact that the average number of years worked in sheet ground (hard rock) was more than 5 in each group, and that five years' steady work with exposure to flint dust is very certain to find the miner in at least the first stage of silicosis. It was found that 243 or 56.1 per cent of the 433 men having miners' consumption, and 54 or 52.4 per cent of the 103 men suffering with tuberculous infection, had commenced to work underground before they were 21 years of age.

While hard work at an early age necessarily often undermines the vitality, the percentage under 21 years among the well men would indicate that immaturity has little to do with the incidence of miners' consumption, though contributing to the rapidity with which these cases break down.

Data as to 198 cases of deaths in 130 families out of 480 families visited were obtained, indicating the average age at death as 37 years, the average number of years mining as 13.7, the average number of years in sheet ground (hard rock) as 8.6, and the average number of years of disability before death as 1 year. Adding the last two figures together it is concluded that in the Joplin district the average case of miners' consumption dies within 10 years after beginning exposure to silicious dust.

An examination of 1,120 children of miners and 1,386 children of nonminers to determine the relation of miners' consumption to living conditions and tuberculous infection did not seem to indicate very much tuberculous infection among those in the first group, "yet we can logically expect, unless precautions are taken, that tuberculous infection will become more and more menacing to public health in the Joplin district. This implies increased danger to adults and to children, with tuberculous infection in miners' consumption occurring more frequently in the first and second stages and earlier in the third stage, and, consequently, directly affecting the safety of the children."

This study of 433 cases of miners' consumption in southwestern Missouri led to the following conclusions:

Miners' consumption is an important occupational disease, widely prevalent among the hard-rock miners of the Joplin district, affecting probably 30 to 35 per cent of them.

Miners' consumption is essentially a pneumonoconiosis, due to the inhalation of silicious rock dust, and resulting in a fibrosis, with loss of function.

The disability and other effects of miners' consumption are due primarily to silicosis, infection being usually a secondary, and often, a terminal process. Infection, both tuberculous and pyogenic, is common in miners' consumption, the tendency to infection increasing as the disease progresses.

The incidence of tubercle infection in miners' consumption is a menace to the public health, affording an unusual opportunity for the spread of tuberculosis. Aside from the hygienic supervision of working conditions underground, education of the miner against the spread of infection and supervision of miners' children, especially those of consumptive parents, are matters of vital importance.

CARBON MONOXIDE POISONING IN THE STEEL INDUSTRY.

The improvement of conditions affecting the health of persons employed in the metallurgical industries is receiving the cooperative attention of the United States Bureau of Mines and the Public Health Service, and several technical papers have been issued by the former bureau as contributions to the literature dealing with this subject. One of these, entitled Health conservation at steel mills, was noted in the MONTHLY REVIEW for November, 1916 (pp. 641 to 643), and two other papers, touching particularly the steel industry, have recently been issued by the Bureau of Mines under the titles Carbon monoxide poisoning in the steel industry, and Occurrence and mitigation of injurious dusts in steel works.3

The object of the paper on carbon monoxide poisoning, as stated in the introduction, is to set forth briefly the liability to this poisoning of those employed in the various departments of the steel plant, the sources of the gas, the extent to which it is present, and its effect on workers, and to make certain recommendations for preventing and remedying such conditions. Attention is given primarily to chronic poisoning—that is, the daily exposure of employees to small quantities of this gas over an extended period of time-rather than to that of acute poisoning, or "gassing," as prevention of this accident is a problem of safety engineering rather than of industrial hygiene.

1 Another paper entitled Safe practice at blast furnaces, a manual for foremen and men, was noted in the MONTHLY REVIEW for November, 1916, pp. 638 to 640.

2 United States. Department of the Interior. Bureau of Mines. Technical paper 156. Carbon Monoxide Poisoning in the Steel Industry, by J. A. Watkins. Washington, 1917. 19 pp.

See p. 85 for a review of this pamphlet.

It appears from this paper that carbon monoxide is the most important of the poisonous gases, and as such is a serious hazard, because experience has taught the difficulty of preventing leaks and the serious and rapid results that follow inhalation. Much in the way of reducing this hazard seems to have been accomplished through the safety-first propaganda, but "the use of gases with a relatively large carbon monoxide content and the occurrence of this gas as a byproduct of many industrial processes, coincident with a general industrial development, have markedly increased in late years. As a result, while the carbon monoxide hazard is minimized in one process, new and constantly changing conditions arise which present additional hazards of poisoning. In no industry have such changeable conditions been more marked than in the steel industry."

In discussing the cumulative effect on men of carbon monoxide inhaled in small quantities daily and over extended periods of time, it is pointed out that some individuals withstand much larger amounts of the gas than others, and that the bodily mechanism is able to adjust itself for a short time to the abnormal conditions produced by the gas. But it must not be inferred from this that man is immune to this gas, for the report states:

Carbon monoxide is a gas of such marked toxic effect that, depending on variable factors such as the resistance of the individual and the quantity of gas inhaled, it is only a question of time until the exposed individual is not only incapacitated for duty but may have his health impaired beyond recovery. Another fact of consequence to employers is that carbon monoxide poisoning renders the worker, though still on duty and not incapacitated, below par physically and also in efficiency. His mental alertness and judgment, as well as his muscular strength and coordination, are impaired. While in this condition he is unable to perform his duties in the manner that will be to the best advantage of his employer.

It seems that in steel mills carbon monoxide may be found about blast furnaces, gas washers and scrubbers, gas engines, gas producers, gas boilers, cupola furnaces, dolomite furnaces, "dinky engines" or small locomotives, and "shanties" or rest rooms for employees. While making a sanitary survey of the steel industry in the Pittsburgh district samples of air were obtained to determine the carbon monoxide content in various places in a steel plant. The result showed the presence of this gas in quantities varying from 0.01 per cent, to which the blower-room force was exposed, to 3.4 per cent, to which the engine-room force near the gas engines was exposed. No physical examination of workers was made, but it is stated that data available from experimental work on carbon monoxide poisoning and from observations made in serious or fatal cases of asphyxiation with this gas justify the statement that exposure to 0.2 per cent of carbon monoxide for a period of 30 minutes 3306°-17-6