THE SYSTEMIC NERVOUS SYSTEM 33 



the discharging agent, responsible for the conveyance of 

 the material from the place of its production within the 

 body and its consignment to the proper delivery agencies 

 within the outermost layers of the cuticular envelope of 

 the body, inasmuch as the circulation of the blood is 

 constantly onward and forward, round and round, without 

 break in its physiological state, and inasmuch as the 

 haemal lympathic circulation is from without inwards, and 

 consequently away from the scene of eruption or ex- 

 cretion. 



We thus eliminate from the category of eruptive 

 factors, except in certain purpuric and other eruptions of 

 a kindred character, where manifestly the blood circulation 

 is primarily implicated, or where, at any rate, it contributes 

 more or less of its corpuscular or haemoglobin elements 

 to the substance and pigmentation of the eruption. In 

 variola h^emorrhagica we have contended that the blood 

 circulation is secondarily invaded from the area of nervine 

 eruption by the breaking down of the interstitial cutaneous 

 elements and the commingling of the toxic and atoxic 

 circulatory media, and consequent re-infection of the affected 

 person by way of the blood circulation. 



The substances erupted or thrown out of the system 

 by the nervine excretionary agencies must necessarily be 

 modified by the nature of the materies morbi, on the one 

 hand, and the particular nervine elements affected by the 

 particular eruptive disease, on the other ; thus a herpes 

 may alone involve the cerebro-spinal lymph, and may 

 begin and end with mere vesiculation at the points of 

 exit of the tainted fluid, or an attack of hyperkeratosis 

 in like manner may be characterised by the eruption or 

 excretion of the true nervine elements, or the medullary 

 and axis cylinder substances, which undergo encrustation 

 and agglutinative changes in virtue of the coagulation of 

 these substances on exposure to the air ; in like manner 

 also eruptions may vary in character in accordance with 

 the nature of the material erupted, as to whether it is 

 one or the other, or a compound of the two, and whether 

 the eruption is lethal enough to disorganise the interstitial 

 connective elements and surrounding cutaneous textures 

 and vasculatures, in which latter case the eruption becomes 



