548 Oa the Nature and Causes of the Decay in Potatoes. 
Although I have told you that fungi are not the cause of the 
disease, still their presence aids very materially in accelerating its 
ravages by their filaments or spawn insinuating themselves be- 
tween the cells and facilitating their decay. Lime is fatal to the 
growth of these fungi, and therefore aids in retarding the progress 
of the disease. I attach little importance to the mode in which 
you procure these three requisites for the preservation of the po- 
tato — dryness, coolness, and removal of contact and decaying 
emanations. Do but ensure these three essential points, and any 
plan will succeed. Only I prefer recommending the use of dry 
mineral materials to organic matters, such as sawdust and straw, 
because these inight possibly also enter into decay and increase the 
evil. 
These recommendations as to storing potatoes refer to those in 
which decay has not manifested itself, for it would be madness to 
mix rotten with sound potatoes. 
But why do I not speak of those popular panaceas which have 
been put forth as checkers or curers of the disease ? Do I not 
know that Morren has recommended chloride of lime ? Am 1 
ignorant that many chemists have pointed to chlorine and sul- 
phurous acid? Is it possible that I have forgotten how to dip po- 
tatoes in nitric acid, how to acidify them with muriatic acid, how 
to dissolve the disease by aqua regia or oil of vitriol, or how to 
puzzle the brains of the peasant with innumerable nostrums and 
impracticable schemes ? 
No, I have not forgotten these ; but I have recollected that I 
am treating of a national calamity, and am not treading the boards 
of my laboratory. 1 have recollected also that gases and acids 
will not build up an imperfectly formed cellular tissue, which is 
the true nature of the disease ; and that although they may arrest 
for a time the progress of decay, they do not do it more effec- 
tually than dryness and exposure to air, and would require a 
nation to become chemists before they produced an extended or 
effectual result. If potatoes are so far gone that they will not 
keep by the means proposed, then ought they to be treated as 
those unfit for human food, which is the subject of my next 
lecture. i 
Lectuiie II. 
On the Treatment of Decayed Potatoes, and on Seed for a future 
Year. By Dr. Lyon Playfair, Consulting Chemist to the 
Royal Agricultural Society. 
In the last Lecture the nature of the so-called disease in the po- 
tato was considered, and shown to i)e a decay of the cellular tissue, 
which was unable to resist the action of external influences. The 
probable cause was considered to be the unusual sunless nature of 
