422 



Here is nii illustr.-ition whicli T ar times use in diseussious with dust 

 victims. 



A man becomes the possessor of an aut<>ni()liil(>, he learns how to run 

 it but knows little or nothing about its internal arrangements. On the 

 road the machine begins to run badl.\'. he knows there is something wrong 

 but can not locate the trouble; he may or may not make an attempt 

 to learn what is wrong; he may conclude to nui tlie machine as long 

 as possible and then turn it over to a master-mechanic to have the 

 ditticulty corrected, lie may bp sutRciently interested to learn about the 

 "iuternal anatomy and physiology" of his machine and just what to do 

 the next time there is trouble, indeed knowing tlie nature of the machine 

 he may look it over at short intervals to avoid trouble on the road. Shall 

 we say that dust in the carbureter is a frequent cause of trouble? 



Any one who has ridden with an experienced and with an inexperi- 

 enced automobilist will appreciate this illustration : He probably noticed 

 the direct method of the one in looking for the source of difficidty on the 

 merest indication of abnormal working of the machinery, and he can not 

 avoid noting the utter helplessness of the inexperienced man when his 

 machine balks ; the latter usually does more hai'm than good in his bung- 

 ling with wrench and hammer trying to make the machine go. 



A dust victim may be regarded as a mtichine that becomes clogged 

 witli dust. Dust iiiterfei'cs in some way with the proper working of the 

 machinery, in time the uiachine may refuse to run. Like the automobilist. 

 he may in time learn much about the signihcance of symptoms, of warn- 

 ings that something is wrong, and he avdids hreaUdnwiis. attacks of ill 

 health and disease. 



Dust Victims. — Individuals wiio react more or less markedly to dust 

 may be regarded as dust victims. In studying a large number of such 

 one can make a composite description of the effects of inhaling dust, of 

 C'oniosis as defined alyove — but in proportion as a brief composite descrip- 

 tion includes inany individuals it nmst be more ov less vague. 



.\n individual as a rule reacts very nuich the same each time under 

 similar exiiosure. Individual reactions howcn-er may differ greatly, so 

 much so that one can speak of tyjies.' 



> In 1004 I (Ifscrihod sovoral tyix's of dust victims, as far as I then under- 

 stood the sulijc'ct. Since then I have been ;r!inn rinu more data, more case reports, 

 but I am not yi-t in a imsitlon to brins tofrether all my data for a complete state- 

 ment. This paper. like all others, must bo regarded as provisional, subject to 

 changes and corroclions. 



