THE NATURAL HISTORY OF TUMOURS 567 



first to lay emphasis upon the fact that the prolonged internal 

 administration of arsenic had sometimes led to the develop- 

 ment of multiple tumours of the skin. The nutrition of the 

 skin becomes affected ; its texture becomes altered, and 

 then, at some spot where continued irritation leads to the 

 rapid production of a number of young cells, a tumour 

 develops. 



A closely similar course of events has been described in 

 connection with some of the aniline dyes, only in this case 

 the tumours do not involve the skin but the urinary organs, 

 and assume different forms according to their origin. Rehn, 

 in 1906, had already collected more than thirty cases of workers 

 in fuchsin who were suffering from some form of tumour of 

 the bladder. Leuenberger has collected many more and has 

 shown that in Basle the deaths caused by tumours of the 

 bladder in the years 1901-1910 were thirty-three times more 

 common among the workers in aniline colours and similar 

 substances than they were among the rest of the male popula- 

 tion ; and that more than half of the cases of tumour of the 

 bladder observed in the last fifty years in the male surgical 

 clinic at Basle came from dyers and those engaged in aniline 

 dye works. Some grew in the bladder ; others in the kidney 

 and ureter ; and, what is of peculiar significance, in some 

 instances the growths did not make their appearance, or at 

 least cause symptoms, until years after the worker had left 

 his employment. A similar condition of things has been 

 recorded of the workers in the cobalt mines of the Schneeberg, 

 only in this case the growths, which are equally varied in their 

 character, are met with in the lungs. 



The tumours that so often follow the continued application 

 to the skin of soot, tar, paraffin, and the like arise in a similar 

 manner. Some substance is absorbed which, in course of 

 time, affects the nutrition and functional activity of the skin, 

 so that it becomes harsh and dry to the touch. The cells 

 that compose it cannot carry on their work as they should. 

 Their development, which depends upon the chemical changes 

 that take place in them during their work, remains imperfect. 

 It comes to an end before it should, while the cells are still 

 in a stage that was perfect for their remote ancestors, but 

 should only have been a transition stage for them, and, ss a 

 consequence, at a time when they are still capable of exercising 



