174 SECTIONAL ADDRESSES. 



workers have a predisposition, and in this respect crystalline silica Is 

 much more harmful than either amorphous silica or carbon. However 

 it acts, whether by direct irritation, by its poisonous properties after 

 solution, by colloidal action, or because it forms locally a nidus suitable 

 for the growth of the tubercle bacillus, will be discussed at a later meeting. 



The report of the Miners' Phthisis Medical Bureau, dealing with the 

 years 1914-1926, shows that the incidence of silicosis is increasing. Of 

 the average number of 178,000 natives employed on the scheduled mines 

 during the year 1925-26, of whom 133,260 were employed underground, 

 simple tuberculosis was found to be present in 566, simple silicosis in 231, 

 and tuberculosis with silicosis in 446. The large majority of cases of 

 compensatable disease among European miners are cases of simple 

 silicosis ; among native labourers the great majority are cases of tuber- 

 culosis, mostly without silicosis. As compared with European miners the 

 incidence of simple silicosis among native labourers is low, which according 

 to the report mentioned is mainly due to the migratory habits of the latter, 

 as silicosis takes time to show evidence. It may also be noted that besides 

 tuberculosis the mortality from Bright' s disease is high in silicosis. 



Workers employed in other dusty trades, such as the preparation of 

 asbestos materials, also suffer from pulmonary disability, and Dr. Collis 

 found that five deaths from phthisis had occurred in five years amongst 

 a staff of less than forty workers employed in a factory where asbestos 

 was woven ; asbestos contains about 50 per cent, of silica. The dust 

 associated with the process of carding, before its extraction was efficient, 

 at one time in England produced a pneumoconiosis resembling that of 

 silicosis. 



It is well recognised that a patient suffering from tuberculosis who is 

 placed under treatment, will, for a time at least, improve in health, no 

 matter what drugs, vaccines or ' specialities ' may be employed. The 

 beneficial result is due, in this as in other disease, to efficient nursing, to 

 the regulation of food, exercise and sleep, and to light and fresh air. If 

 only this effect were clearly recognised the number of ' treatments ' in 

 vogue for this common disease might be diminished. The enthusiastic 

 physician sometimes begins the new treatment as soon as the patient 

 enters his wards, and he is apt to regard the benefits which may follow as 

 due to the special treatment. General hygienic measures are of primary 

 importance in treatment, and it is not until all the beneficial effects 

 which are known to ensue from these have been exhausted that the 

 physician has any right to ascribe an effect, beneficial or otherwise, to a 

 special treatment. 



Drugs are employed in tuberculosis either with the object of attacking 

 and preventing the growth of the tubercle bacillus or other organisms 

 with which the disease may be associated, of neutralising poisonous 

 toxins, or of removing or relieving symptoms. It is with the first group 

 that I am now concerned. Two groups of organic compounds are especially 

 remarkable for their chemo-therapeutic action on bacteria. The first 

 group has the quinine complex ; quinine is the methyl-ester of cupreine 

 and it can be reduced by nascent hydrogen to form hydrocupreine. The 

 following table shows the effect of two derivatives of hydrocupreine in 

 arresting the growth of certain micro-organisms. 



