55 
They stain more deeply and brightly than the sporo- 
blasts, and cannot be mistaken for these. Thélohan 
does not describe them, and since mine are all ripe 
eysts I have no means of ascertaining their origin 
and significance. Passing inwards we come to clusters 
of ripe spores, and these soon almost entirely 
replace the endoplasm, snd run together to form 
the central mass of spores, the organelle themselves 
having broken down and disappeared. Often, however, I 
noticed, as it were, tongues of endoplasm projecting inter- 
nally towards the centre, and in some sections appearing 
as isolated patches, some of which were fertile, but others 
apparently sterile. These are not to be confounded with 
the islands of residual-tissue described below. Although 
I have examined sections through many cysts, I have 
not seen any instances of the degeneration of the spores 
such as is described in the central part of “ over-ripe ” 
cysts. In all mine, the central spores are as healthy in 
appearance and as deeply-staining as those of the peri- 
phery. A noteworthy difference in the central mass of an 
A cyst from that of a B one, is the absence in the former 
of the areas or patches which are the more or less colloidal 
residua of the degeneration of tissue-cells, &c., of the host. 
Moreover, the spores themselves in the former case are 
quite free, and not embedded in any matrix. These facts, 
together with those already set forth, emphasize the dis- 
tinction which I wish to bring out between the two kinds 
of cyst. While the one (A) is practically all parasitic 
tissue, and represents one individual, the other (B)—the 
pseudocyst—is the consequence of the massing together 
and circumscribing of (a portion of) an infiltrated area, 
originally comprising many tiny, daughter, individuals 
(of which, im an old pseudocyst, nothing is left save 
spores) diffused in and among the host’s tissue (also 
