farmers' m 1 s c k l I, a n y . 97 



» 

 The first application was salt, and the action of this was so instan- 

 taneous and decided, that I did not proceed to any other. 



A portion of the dark substance was placed on a piece of glass, 

 on the microscope-stand, in a drop of distilled water, and then 

 thoroughly examined. A little salt, on the fine point of a pen- 

 knife, was then added ; a nearly instantaneous change took place 

 — the dark-colored masses separated, much of them seemed to pass 

 away, and instead appeared numerous dark slate-colored bodies, 

 which I easily recognized as the spores, or reproducing bodies of 

 the fungus. With the grey, slimy substance, the effect was still 

 more striking : all the indistinct slime disappeared — the mass 

 became clear and transparent, and left nothing but these innumera- 

 ble dark globules floating about in the drop of water. 



It seemed to me, that the salt destroyed all the vegetation of the 

 fungus, leaving nothing but the reproducing spores, which are in- 

 destructible by salt. The spores of fungi are the bodies by which 

 they are reproduced and spread, and are analogous to the seeds of 

 other vegetables, and these spores are generated in such enormous 

 quantities, that many fungi, like this on the potatoe, spread with 

 inconceivable rapidity ; but in order to vegetate, they require cer- 

 tain favorable conditions and circumstances, which yet require 

 much investigation. These favorable circumstances are, in my 

 opinion, prevented by salt, as it destroys the fungus vegetation. 

 Therefore, wherever the disease existed this year, I recommend a 

 liberal supply of salt to be spread on the soil, and trust it will 

 eradicate the evil. It is, at all events, a remedy which cannot do 

 much injury, if it does not succeed. 



During the examination of the black substance, I of course 

 recognized the grains of starch, which appeared sound ; but wish- 

 ing to know whether the fungus had affected them, I added a lit- 

 tle iodine. The grains immediately took the usual purple color, 

 and I think were not at all injured ; indeed, it appears to me, that 

 the injury takes place by the rupture of the cellular parts of the 

 potatoe. 



I am aware that it requires some practice to judge well of the 

 appearances under the microscope ; but I repeated these examina- 

 tions six or seven times, and always with the same results : still, I 

 s;hould be very glad to have them repeated by others, whether their 

 correctness be confirmed or not. 



VOL. 1. NO. 1. N 



