624, W. S. PERRIN. 
a number of discrete particles. With Giemsa it stains bright 
red, with hematoxylin, however, but faintly, in marked con- 
trast to the residual nuclei (figs. 30—33). Later, the nucleus 
condenses to form a sphere containing a central particle 
(fig. 31). This sphere stains faintly at first, but as it con- 
tracts the staining becomes much deeper (figs. 32, 40—42). 
The now compact and deeply staining nucleus shifts its 
position from the centre to the end of the spore, in corre- 
spondence with the development of a vacuole with highly 
refractive contents. 
Figs. 41—43 illustrate the gradual development of this 
vacuole and the shifting of the nucleus, which now divides 
into two, the daughter nuclei moving to the centre of the 
spore (figs. 44—47). Fig. 47 indicates that the two nuclei 
are once more dividing. Later stages than the above have 
not been satisfactorily stained owing to the very resistent 
nature of the spore coat. While these nuclear changes have 
been taking place the spore has been surrounding itself with 
a spore coat or shell. This, as shown in fig. 49, consists of 
two halves meeting ina median suture. It is presumably 
through this suture that the sporoplasm when infecting a new 
host makes its exit. The spore in its final form is a flat 
oblong structure rounded at the ends (figs. 48, 49), varying 
from 5 ~—6 pw in length, and 2°54—3y in breadth. In the 
living state the sporoplasm is finely granular, and at one end 
of the spore a small highly-refractive globule is present. The 
relation of the polar capsule, which is almost certainly present, 
to the vacuole described above and the refractive globule I 
have, as yet, been unable to determine. Application of the usual 
reagents—ether, concentrated sulphuric, nitric, and hydro- 
chloric acids, glycerin, iodine, and boiling water, etc.—has 
hitherto failed to procure extrusion of the filament of the cap- 
sule. Experiments now in progress will, I hope, throw further 
light upon this point. The spore coat is unaffected by the 
above-mentioned reagents, and also by ‘eau de Javelle’ (sodium 
hypochlorite). Attempts to produce the emergence of the 
sporoplasm from the spore by treating the feces with the 
