METALLIC AND LEAD POISONING 129 



This view holds good, of course, only in cases of the 

 internal and, consequently, general poisonous effects by 

 the substances in question, and not in such cases as " drop- 

 wrist" in painters, where the local pathological condition 

 is due to the cutaneous absorption of lead through the 

 open sweat ducts, and its passage thence through the sweat 

 glands proper along the inter-neurilemmar spaces of the 

 sensory or peripheral nerve fibrils, terminating in the 

 glands from which these ducts proceed to points high 

 enough in the course of the common nerve trunk or trunks 

 to enable it to pass up to and regurgitate or turn back 

 into the inter-neurilemmar spaces of the accompanying 

 motor nerve or nerves, along which it retrogrades or 

 returns, or rather passes forward^ into the sarcolemmar 

 intra-spaces of the affected muscles, where its poisonous 

 effects become apparent in the production of paralysis 

 through its deleterious influence on their sarcous elements. 

 Thus, moreover, we account for the confinement of the 

 pathological characteristics of this disease drop-wrist 

 within strictly defined and local limits, these changes being 

 due to and consequent on the liquefaction of the lead by 

 the sweat, it may be, its subsequent passage through the 

 sweat glands, and thence along the peripheral or efferent 

 nerve fibre inter-spaces and textures to the points in the 

 common neurilemmar nerve sheaths, where the efferent 

 or implicated motor nerve fibres leave, to be distributed to 

 the paralysed muscles, and whence the poison finds its 

 way into their intimate substance along the nerve terminal 

 fibrils supplying them. 



A local preference or affinity, we think, is thus demon- 

 strated, due to progress, it may be, along the lines of 

 least resistance between the invading mineral poison, the 

 motor nerve fibres, and the sarcous elements of the affected 

 muscles, as compared with the neutral influence exercised 

 on the sensory nerve fibres and the local sensory pheno- 

 mena. We think, moreover, that an analysis of the 

 effects of general lead poisoning will demonstrate the same 

 inference and lead to a similar conclusion as to the existence 

 of the same affinity generally between lead and motor 

 nerve textures, including cells, and fibres, and- muscle 

 elements. 



