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The germination of the resting-spores was awaited with the greatest anxiety, 
and as I never knew from one day to another whether or not these bodies might 
all collapse and perish, I was under the necessity of dividing the material, and 
keeping a constant look-out for results under different conditions. With this 
object in view, therefore, I kept some of the bodies moist in pure water, others in 
diluted expressed juice of horse-dung, others in expressed juice of fresh Potato 
leaves, others upon extremely thin slices of Potato and on crushed Potato mash, 
others in saccharine fluid, others in nitrogen gas, some between pieces of glass 
kept constantly moist, some upon broken tile (also kept constantly moist), and 
some upon Potato leaves as they grew upon the living plant. Besides this I have 
had a quarter of a hundred of slides, kept damp, and under examination every 
day (almost night and day) for the last three months, All these preparations I 
have kept constantly and uniformly moist under darkened bell-glasses, for dark- 
ness invariably assists the growth of spores of all sorts. 
The first new fact worthy of note is this: many of the resting-spores grew 
in size during nine months of their rest to twice their original diameter, or about 
four times their original bulk, and their aspect gradually changed from almost 
smooth, semi-transparent bladders to brown, more or less rough and warted or 
echinulate spheres, These latter brown, mature bodies were quite the same 
in character with those so sparingly seen last June and July. How they arose last 
year no one saw, but probably the wet weather of the early summer caused their 
appearance. It does not follow, because the resting-spores have taken a year to 
artificially mature with me, that therefore they always take a year to ripen ; it is 
quite possible that, in a state of Nature and under different conditions, they may 
mature rapidly. At any rate, two sorts of bodies were seen together last year, 
transparent smooth bodies, and rough brown ones. I considered them to be 
different states of the same resting-spores, and subsequent facts have proved my 
supposition to be quite correct, 
The top row of illustrations on fig. 1 shows characteristic conditions of the 
almost mature reproductive bodies as drawn in April last. At A is seen the 
oospore (or resting-spore) within the oogonium (bladder which holds the resting- 
spore), at B may be seen two resting-spores within one oogonium, and at c three 
resting-spores within one oogonium, whilst at D is shown a double oogonium— 
two oogonia coalesced, and each oogonium containing a resting-spore. 
At the end of April and beginning of May last I began to see the first signs 
of germination, and at this time many of the oospores proved effete ; the oogonium 
cracked at E, or became broken into atoms, as at F, discharging a bladder, as at G, 
which perished in fine dust, as at H. 
As the month of May progressed many of the resting-spores became dense 
and dark, with the oospore occupying the whole of the oogonium, as at1; this 
condition is different from that of the body a, for in this the resting-spore, being 
not quite mature, does not yet occupy all the oogonium, but floats within from 
side to side, as the object happens to be moved under the microscope. J shows 
the contents of oospore being broken up into zoospores ; K shows the zoospores 
