10 THE NORTHERN MICROSCOPIST. 
they find a suitable start into life for themselves. Such is the case 
with many Fungi, they will in hybernation undergo excessive varia- 
tions of wet and dry, of heat and cold, without being destroyed. 
This will account for the sudden appearance of fungi after the in- 
terval of many years since the time they were last seen. Many of 
these plants form themselves into a hard substance called sclerotia. 
They may often be found, and are found too on all sorts of 
substances. ‘They are a mass of cells destitute of fruit. Many of 
the mushroom tribe are at certain periods of their existence con- 
stantly connected with the sclerotia, in which dormant state they 
await their time of development. It must be very interesting to 
obtain these plants, and to induce them to grow; one point of 
course being of great assistance in their development, viz., that 
they should be kept as nearly as possible in their original state. If 
they grow on sticks, take the stick and never let it appreciate the 
fact that it has been moved. The same exactly with all the 
sclerotia. By adopting this plan some very beautiful Fungi have 
been obtained and added to the list as new species. 
Reverting, however, to the resting spore of the potatoe disease, 
as yet there has not appeared anything to destroy it, and certainly 
the difficulty in its destruction must be enormous. Wet places are 
vastly more likely to produce it than dry ones. Wet seasons en- 
courage its growth more than the reverse. The same ground 
should not be used for years together for the growth of the potatoe. 
Every haulm should be burned, and every root or rootlet. It should 
never go near decaying substances used for manure. Those 
varieties of potatoe which are the least affected by the disease, 
such as the very earliest sorts, should be encouraged, so should the 
red kinds of winter potatoes rather than the white. My own idea 
is that as a special intervention of God brought the disease here, so 
a special withdrawal of it by the Almighty will exterminate it. It 
is not as though the common potatoe were only attacked. The 
potatoe belongs to the family Solanum. Eleven of the Solana are 
recorded as having developed the disease, so has Arthocerts viscosa. 
Time passes. I must begin to close this paper. Some of you 
doubtless will be very disappointed that I have not said a great 
deal about the poisonous Fungi and contrasted them with those 
that may be eaten, laying down royal. roads whereby the youngest 
student may be able to say whether he is going to be poisoned or 
not, if during the next season he is spared health and strength. To 
be candid, I know scarcely anything at. all about the Fungi to which 
the edible and poisonous ones belong, nor is it my intention for a 
long time, if ever, to study them ; they are a section of themselves, 
and are in very good hands indeed. _My work has been almost 
exclusively amongst the fungi which must be studied with a micros- 
cope, particularly those which are parasitic on leaves. To take up 

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