24 Observations upon the Potato Rot. 



their connection with the root; that is, their texture is entirely 

 destroyed, and they are in a brittle, decayed state. Some- 

 times one stalk only in a hill is in this condition, and the 

 tuber or tubers connected with that stalk, will be found 

 affected with the rot. 



After the potatoes are harvested, those on which the black 

 specks above described are found, will decay ; but in the pro- 

 cess of decay, I have not found that they affected sound 

 tubers, and caused them to rot. The disease cannot be com- 

 municated ifi this way ; it must pass through the several 

 stages aforenamed. There may be instances in which tubers 

 slightly affected, or containing merely the germs of the dis- 

 ease, from peculiar causes, will remain sound through the 

 winter, and it may be in this way that the disease is propa- 

 gated from year to year. But of the correctness of this sug- 

 gestion, I am not fully satisfied. It needs to be confirmed by 

 observation. Those who are acquainted with the natural 

 history of the Fungus tribe, are aware, that their sporules, or 

 seeds, are exceedingly minute and numerous. Probably mil- 

 lions proceed from a single plant. Besides, these seeds are so 

 light, being but a mere dust, as seen by the naked eye, that 

 they are easily wafted about, and so minute, that they might 

 attack a plant without being perceived, until they had reach- 

 ed their maturity. It is owing to this, that the disease pre- 

 vails so extensively, and it may be that it has thus been prop- 

 agated even across the ocean. The wide prevalence of the 

 disease, indeed, will be no matter of surprise to those accus- 

 tomed to the enlarged views of the diffusion and propagation 

 of plants, which an acquaintance with Botany furnishes. 



I have prepared specimens, illustrating the progress of the 

 disease under consideration, which I should be happy to show 

 to any one desiring further information. The fungus which 

 attacks the potato is very small, so much so, that it is proba- 

 ble there are no glasses of sufficient power to render their 

 seeds visible. Yet, that they have seeds, no one can doubt. 



The specimens to which I have alluded, show the fungus 

 upon the outside of the stalk; next upon the pith or inside; 

 next upon the interior of the root ; next upon the skin of the 

 tuber ; and, last of all, in the cells of the tubers themselves. I 

 have also prepared specimens, showing the different appear- 

 ance of the healthy and the diseased plant. 



