298 Trow . — Observations on the Biology and 
distribution of the nuclei. The section adjacent to that repre- 
sented in Fig. 47 was conspicuous for its vacuoles and the 
small number of nuclei. The following countings may be 
of interest. One section of a conidium \x in diameter had 
three nuclei, five sections each 14 \x in diameter showed 
respectively 8, 7, 8, 6, and 5 nuclei, and four sections each 
16/x in diameter showed respectively 10, 6, 6, and 11. 
Figs. 48 and 49 are drawn from material preserved in 
chromacetic acid. Fresh conidia were placed in cabbage- 
solution for about an hour and then fixed. The nuclei are 
very distinct, but the finer details are not so sharp as in 
material fixed with Flemming’s or Hermann’s solutions. 
The beautiful reticulate structure of the cytoplasm is likewise 
absent. The plane of section in the case shown in Fig. 49 
was parallel to the direction of one of the germ-tubes. One 
spindle is seen in these figures quite comparable to those 
present at other stages, and three cases of ‘ double ’ nuclei. 
One is obviously justified in describing the first stage in the 
germination of the oospores as the conversion of the oospore 
into a conidium. One can easily understand, now that the 
cytological details are known, the peculiar behaviour of the 
oospores in germination. There appears to be no necessity 
for tracing the development of the germ-tube in the germinat- 
ing oospore, for the behaviour must correspond exactly to 
that described and figured in the case of the conidia. The 
structure of the hyphae has been frequently observed, and 
corresponds to that shown in the germ-tube of Fig. 49. We 
have then before us a clear picture of the cytological details 
at all stages of the life history. Certain gaps in our know- 
ledge, indeed, remain to be filled up, but these are of minor 
importance. 
It may be of advantage to bring together the observations 
made on the structure of the nucleus. The resting nucleus 
is vesicular with a distinct nuclear membrane. In the centre 
is a chromatic mass, and traversing the ‘ nuclear sap ’ between 
this and the nuclear membrane is a very delicate network 
of ‘ linin ’ threads with very little chromatin attached to them. 
