AN INTRODUCTION TO THE STUDY OF FUNGI. 9 

branches. This we call the “zoospore.” Its structure is very 
different to the one about which we were just speaking. It is 
capable of division into a number—say about 8—of atoms. The 
atoms have a lash-like tail, and they have the power of propelling 
themselves by means of these appendages for hours or even days 
together. When their travelling ceases, their corrosive particles 
work similarly to the dust-like spores. Still these lash-like things 
are more able to extend the disease than the others, because their 
wonderful power of locomotion is so great. Hence a warm wet 
day or night is very favorable indeed to the propagation of the 
disease. 
These two kinds of spores, it has been said, cannot exist through 
the winter. The question then naturally comes, If two kinds of 
seeds do their destructive work only in summer and die, how is 
the disease propagated? This is just the puzzle which has harassed 
the minds of the ablest men of the day, and which has gained for 
my friend Mr. Worthington G. Smith his gold medal for the dis- 
covery. In addition to the two spores named above, the third has 
been found by Mr. Smith, which exists all the winter and spring in 
a dormant state, but in June and July is only waiting to find a 
tuber so that it may produce the disease and continue its existence. 
The way in which Mr. Smith found it was simply this. He 
collected together a great number of brown spotted leaves such as 
those we have been considering. These he kept moist during the 
whole of the winter at the cost of a good deal of labour and 
trouble. Mr. Broome did the same. The consequence was that 
these moist leaves produced a quantity of mycelium threads, in- 
cluding the long looked for and missing link which is called the 
oospore or resting spore. If it could be destroyed we should be 
free from the potatoe disease. But this spore lives through the 
winter. Every diseased potatoe you leave to be buried in the 
ground deposits vast numbers of these resting spores ; every haulm 
you put to the manure heap to rot for future use only increases the 
disease. This spore too undergoes a beautiful process in order to 
become fruitful. It has its mate, for vegetable life is like animal 
life,—it needs its partner. There is the resting spore. It is pierced 
by a beak like projection—a change takes place almost at once. 
The beak like thing has completed its mission, and the spore 
which has been pierced awaits its time and opportunity to grow, 
which of itself it could not have done. Thus we find that the two 
divisions of Phanerogamic Botany and Cryptogamic Botany are 
merely man’s invention through his not having been acquainted 
with the wonders God has revealed through the microscope, and 
thus we find too that the divisions can exist no more in reality, 
although for convenience the terms may be used. These resting 
spores for all we know may live for years without growing unless 

