318 ON THE MATURATION OF GRAIN 



unhealthy condition; and like all organised matter, 

 wherein azote exists as a constituent, has a strong 

 tendency to run into decomposition, when not 

 checked by an excess of carbon. The alkaline 

 portions free themselves from their combinations, 

 and form ammonia. Hence the foetid smell of 

 decayed diseased tubers. This first deranges 

 the cellules next to the skin, and during this 

 period the progress of the disease is slow. But 

 the brown fluid by degrees dissolves the cellules, 

 and by leaving the granules of starch intact, 

 cavities are formed thereby in the substance of the 

 tuber, wherein soon develope themselves various 

 kinds of fungi, as the Polyactis alba, Spicaria 

 Solani, Fusisporium Solani, F — didymum F — 

 candidum, &c. These fungi seem to spring from 

 the amorphous mass of dissolved cellules, as 

 therein we first observe the filaments of their 

 several mycelia ; and increasing speedily within, 

 at length rupture the epidermis, and then assume 

 their several generic and specific characters. The 

 murrain now spreads rapidly, and penetrates the 

 internal parts, making cavities in its progress, 

 wherein the fungi form and mature themselves ; 

 and the granules of starch before intact are now 

 infected, and assume the brown tint of the mur- 

 rain, have their external lamina dissolved thereby, 



