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127 types. The relationship between the different somato- types and carefully assessed and established bodily disease provides a fruitful field for research. But if this study is to attain the dignity of a science full considera- tion must be given to every environmental factor, both physical and socio-economic. AVOIDABLE CANCER THOUGH cancer of the scrotum contributes less than 8% of the deaths caused annually by cancer of the skin, there were 1335 scrotal cancers out of 3333 notified cases of occupational skin cancer between 1920 and 1943. More than half of these (793) occurred among cotton mule spinners who come into contact with mineral lubricating-oil. The remainder of the 3333 cases were distributed over a wide variety of trades falling naturally into two main groups, in one of which there is contact with pitch, tar, and bitumen and in the other with shale and mineral oils. That this is not the whole story of carcinogenic agents and occupation is indicated by Henry’s prodigious investigations of the occupa- tional histories of people whose deaths were notified to the Registrar-General as caused by cancer of the scrotum. He gives his results in a table which lists 101 separate occupations, together with proved or- suspected carcinogens such as mineral oil, tar, pitch, soot, creosote, arsenic, and " heat with radiations." The estimated incidence in -the populations at risk shows that scrotal cancer is highest in chimney sweeps ; then come patent fuel workers, cotton mule spinners, textile spinners, and tar distillery workers, in that order. Surprising information is obtained when a case is fully investigated. " It was naturally interesting," writes Henry," to expose the parish clerk as a gasworks stoker ; the mineral-water manufacturer, the traveller in vinegar, and the musician as cotton mule spinners ... the grocer as a patent fuel worker ... the general labourer as a chimney sweep ; these discoveries giving the answer to the problem." But he experienced even greater interest and a healthy feeling of frustration when he found that the fish porter was a conjuror, the cotton ware- houseman a pugilist, and a painter an ex-acrobat- revelations which threw no light on the problem. It was not until the inquiry was under way that he began to appreciate fully the possibilities of medicinal treatment (e.g., by arsenic) as a cause of cancer, and he hopes that others will follow up this line of investigation. Henry admits that the best method of preventing scrotal cancer is to use a non-carcinogenic material in industry instead of a carcinogenic one, but unfortunately he emphasises the practical difficulties of choosing the correct oil and of obtaining enough of ’it. Presumably there are shipping and other difficulties at present, but we wish he had thrown official caution to the wind and come down heavily for the prohibition of mineral oil as a lubricant for cotton mule spinning-machines. These machines used to be lubricated with sperm and neatsfoot oils, and it was only after the introduction of mineral oils that cases of mule-spinners’ cancer began to appear. It is hard to believe that such a simple preventive measure as the use of non-carcinogenic oils could not be adopted. As far as is known vegetable oils are not carcinogenic, and in normal times they are not scarce, though possibly they are more costly than mineral oils. There is greater difficulty in controlling the dusts of tar and pitch, and for many purposes substitutes cannot be found. It is odd that the products of coal and petrol which have lain under the earth for centuries should have carcinogenic properties whereas products of living 1. Henry, S. A. Cancer of the Scrotum in Relation to Occupation. London : Oxford University Press. Pp. 112. 15s. plants have not. Henry looks back to the time of Pott, and the discovery of chimney sweeps’ cancer ; and he wishes for a magic carpet to take us back 200 years to find out what was the incidence of scrotal cancer in those days, and forward to the time when the deposits of coal and petrol have been consumed, to see whether there will still be scrotal cancers. He ends with an apt quotation from George Moore : " In two hundred years there will be fields where today there are cinder heaps.... But coal and petrol are not endless even in America ; and as soon as both are among the gone, the world will start on a new race again." MILK INDUSTRIES COMPARED THE mission that has been studying milk-production in North America 1 says that there, as here, the milk industry is largely based on the family farm carrying 15-30 milking cows ; and economists hold that larger units are not inherently more efficient. By trade-union standards the family is grossly overworked, and the hired farm-worker receives only about half the reward of the milk roundsman, although his work is certainly more exacting and more skilled. In general, the pastures are inferior to those in Britain, but maize-corn and lucerne are important fodder-crops which might have more attention in this country. In most of the Eastern States nearly all the farms have electrical equipment, and the mission thinks that a supply of electricity would provide the greatest single improvement on our dairy- farms.. (On many of them, however, a proper water- supply is needed more.) Steam sterilisation of utensils and milking machines is less common than in Great Britain : chlorine disinfectants and lye solution (0.5% NaOH) are used, and special attention is paid to cooling of milk which is done by standing churns in cooling tanks. In addition, all milk is pasteurised when it reaches the depots. The health authorities are finally responsible for hygienic standards, but much of the milk-testing is done by the large dairy firms. Milking-parlours are still in the experimental stage. The price of milk is related to its butter-fat content and " Golden Guernsey milk" brings a higher return to the producer. The mission strongly recommends that a similar scheme, or one related to the total solids, should be introduced in Great Britain .; but otherwise they believe that the milk-contract system in this country is much superior to those in America. In a land of domestic refrigerators milk may be delivered only once every two days, and much of it is bought from shops in cartons. The report shows that production of milk is probably more efficient than it is here. The average annual yield of cows is about 100 gallons (approximately 15%) higher than in Britain and replacement costs are lower. The higher yield has been largely achieved by using Holstein Friesian cattle, which give the best return even though payment is made on a butter-fat basis, and by a .more consistent policy of breeding for high milk-production. Long-term experiments at Beltsville are indicating that the use of proven sires (known to throw heifers giving high yields) is as effective as intricate line-breeding programmes for raising milk-yields, and artificial insemination enables the best use to be made of proven bulls. The mission advocates further breeding research in this country and more use of artificial insemi- nation in order to develop single-purpose dairy animals. In his classical work on breeding dairy cattle, however, Prentice 2 emphasised that the beef qualities of dairy cows may, under certain conditions, be an important factor in the economics of dairying, and the Shorthorn is still widely used in the less intensive dairying district? 1. Agriculture Overseas. Report no. 1 : Milk in North America H.M. Stationery Office. 1946. Pp. 64. 1s. 3d. 2. Prentice, E. P. American Dairy Cattle. New York and London 1942. Pp. 453.
