174 PRESENCE OF GERMS 



thereby. The character of the eruption is determined 

 mainly, and in some cases entirely, by the abnormal 

 state of the capillary circulation, and even in those 

 instances in which local alterations in vascular tension 

 are unquestionably associated with nervous disturbance, 

 this is often induced indirectly by a primary change 

 in the capillary circulation, by which the afferent nerv.e 

 fibres passing to the ganglia, are influenced. Disturb- 

 ance consequently occurs in the ganglion, and the 

 central variation excited in the intensity of the current 

 is conducted along the efferent vaso-motor arterial 

 nerves. In consequence, many little arteries become 

 dilated, and the vascularity of the area of tissue sup- 

 plied by them is increased. 



In all cases of contagious disease which I have 

 examined, the same sort of living germinal or bioplas- 

 tic matter has been discovered in the capillary vessels 

 of many of the affected tissues of the body. In some 

 parts the vessels appear to be quite filled with a 

 " granular," more or less transparent material, which, 

 when fresh, may be stained by the carmine fluid, and 

 exhibits the characters of bioplasm, the particles of 

 which are, however, exceedingly minute. 



I cannot explain fully and satisfactorily why the 

 contagious material collects principally in the capil- 

 laries of the skin and mucous membranes, but I would 

 remark that the masses of bioplasm in connexion with 

 the surface capillaries are large, and project into their 

 interior, Plate XVI, fig. 58, p. 136. Thus there are 



