178 



PROTISTS AND DISEASE 



1894, any spreading sore that resisted the oral administration 

 of mercury was excised. I thought that near the margin of 

 rapidly spreading secondary ulcers the parasites would be 

 found in epithelial cells just in advance of the leucocytes : 



ny^ * 



FIG. 52. PART OF THE EPIDERMIS IN A SECTION OF A SPREADING 

 SECONDARY SYPHILITIC ULCER, a, Horny layer ; b, normal nucleus 

 of epidermal cell ; c and d, nuclei of epidermal cells that are breaking 

 up ; u, v, w, x, y and z, various stages of the bodies described as 

 protozoa by the author in 1895. Two leucocytes are present among 

 the minute bodies at z. Reduced from a drawing made with drawing 

 eye-piece and yinch oil-immersion lens. From Part II. 



this proved to be the case as shown in Fig. 52. In the section 

 are seen large pycnoplasson parasites ; these are linked by 

 stages to others breaking up into minute nucleated elements : 

 only when this subdivision occurs do the parasites attract 

 leucocytes as at z. 



