422 



Here is an illustration which I at times use in discussions with dust 

 victims. 



A man becomes tlie possessor of an automobile, lie learns how to run 

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

 road the machine begins to run badly, 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 run the machine as long 

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

 difficulty corrected, lie may be sufficiently interested to learn about the 

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

 the next time there is trouble, indeed knowing the 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 difficulty 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 harm than good in his bung- 

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



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

 with dust. Dust interferes in some way with the proper working of the 

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

 he may in time loarn much about the significance of symptoms, of warn- 

 ings that something is wrong, and lit' avoids breakdowns, attacks of ill 

 health and disease. 



Dust Victims. — Individuals who 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 

 Coniosis as defined above — but in in-o])ortion as a brief comimsite descrip- 

 tion includes many individuals it must be more or less vague. 



An individual as a rule reacts very much the same each time under 

 similar exposure. Individual reactions however may differ greatly, so 

 much so that one can speak of types.' 



1 In 1904 I df-scrihod several types of dust victims, as far as I then under- 

 stood the subject. Since then I have been gatherine: more data, more case reports, 

 but I am not yet in a position to bring together all my data for a complete state- 

 ment. This pai)er. like all others, must be regarded as provisional, subject to 

 changes and corrections. 



