On the Potato Disease. 
S83 
account for one person escaping from a malignant epidemic to 
which his neighbour fell a viclim as to account for every ])hase of 
tliis mysterious visitation. But if the rusty spots on the under- 
ground stems are carefully examined, it will be found that small 
while specks of mildew exist between the bark and woody part, 
and also frequently occupy the internal tissue of the bark itself, 
even in a greenish state. 
There are apparently t\>o species; in an early stage being 
somewhat like jelly, but in a more perfect form resembling the 
accompanying drawings (Figs. 1 and 2), one species being not 
1, Inside of bark, unilerneatli a rusty spot, on undergronnil stem of polalo, showing a niiml)er of 
wliilc specks of mildew in an eailv stage, the brown spot not having encircled the stem. 
Sept. 7. 
2. Mo3t likely the above mildew in a more perfect state. The sporidia, being very transparent, 
appeared to be tilled with spores ; some had burst. On inner bark of underground stem of 
potato. Sept, 8. 
IJotrytis infestans. on green tomato, diseased like the potato. 
5 ,~.nd 6. The same on ripe tomato, outside and insido of a blotch, beautifully vitreous, Sept. 20, 
4. Another species on diseased tomato. 
7. Hotr^'tis parasitica, on letttice leaves. Sept. 2t. 
5. White mould on underground stem of potato. 
9. White mould on scab on potato, apparently identical with No. 8, 
unlike that produced on the scab (Figs. 8 and 9) ; but I have 
not been able to ascertain the names of them, 7^" t/iet/ have avy. 
With regard to these species I ?m of opinion that, like the 
botrytis, their pro];er food is vegetable matter in an unhealthy 
condition. I shall only further observe with respect to fungi, 
that many species have been unusually prevalent this autumn; 
