1100 PROF, E. A. MINCHIN ON [Dec. 10, 



forming, so to speak, a band i-ouncl the waist of the parasite ; in 

 many cases, however, it is an " Empire " waist, placed much nearer 

 one end of the body than the other. As I have laboured to 

 reproduce the appearance of the objects in my illustrations, I need 

 not enter into longer descriptions. While, as is shown, some 

 parasites have slightly more chromatin than others, there is 

 nothing that can be said to be in the least transitional to the 

 forms next to be described. 



The full-grown intra-corpuscular parasites are at least | the 

 length of the blood-corpuscle, i. e. about 15-17 ^ in length by about 

 5 /Lt in breadth. They contrast sharply with the young forms in 

 the characters both of the body and nucleus, but especially the 

 latter (PL LY. figs. 6-8). The body appears distinctly contoured 

 and shaded, standing well ofi' from the blood-corjjuscle ; it some- 

 times lies in a distinct clear space (figs. 6 & 7), but I could not 

 make out anything of the nature of a capsule surrounding it. 

 The cytoplasm is finely granular and takes a distinct bluish stain ; 

 only in one instance did I observe in the cytoplasm what appeared 

 to be a grain of chromatin distinct from the nucleus, in a parasite 

 which appeared to be ripe for escape from the corpuscle (fig. 8), 

 But the nucleus is the most remarkable featui-e of the parasite at 

 this stage, as compared with the forms described in the preceding 

 paragraph ; it is exceedingly rich in chromatin, which forms a 

 deeply staining mass of irregularly spongy texture, occupying the 

 middle region of the body for practically its whole width and 

 nearly one-third of its length. Here, again, I must leave my 

 illustrations to sjDeak for themselves ; I think they make the 

 contrast between the young and old forms of the parasite 

 sufficiently plain. 



Of the free vermicules, it can be said that they resemble closely 

 the full-grown intra-corpuscular forms. Their principal variations 

 of form and structure are shown on PI. LY. figs. 10-15 ; we can 

 distinguish in a general way stumpy forms (fig. 10), medium 

 forms (figs. 11-13), and long forms (figs. 14, 15), the last-named 

 being by far the most abundant. One end of the body is always 

 slightly clubbed, and the nucleus may be nearer to the stouter 

 end, or to the narrower end, or to the middle of the body. The 

 nucleus shows the same spongy structure described above for the 

 intra-corpuscular parasites ; it may vary in texture from a coarse 

 to a more finely-knitted texture. Only in one case did I observe 

 a tendency for the chromatin to take the form of more or less 

 distinct masses (fig. 13). 



I have figured (PI. LY. fig. 9) one of the two cases in which I 

 found the vermicule in the act, apparently, of escaping from the 

 corpuscle. But even after examining the preparation by the aid 

 of different objectives and various methods of illumination, I was 

 not able to make up my mind exactly as to how the appearances 

 seen should be interpreted in some points. My impression is that 

 the projecting extremity of the parasite is rounded ofi*, and that 

 the conical pointed end seen in my figure represents something of 



