62 The Potatoe Plague. 



The infection soon descends into the tubercle itself. If 

 the disease follows its course, the tubercle mortifies forthwith. 

 A potatoe is not a root, but a branch, whence it follows that a 

 tubercle contains a marrow, which is the eatable part to be 

 preferred, and a separate rind ; between the marrow and the 

 rind there is a zone of vessels, which represent wood. This 

 construction is apparent to any one who chooses to cut a thin 

 slice of potatoe, and place it between his eye and the day 

 light. The infection attacks that part which receives the sap 

 on its descent. 



By following the progress of the evil upon a great number 

 of tainted tubercles, I have been able to see how the evil, by 

 one continuous progress, at length reaches the heart itself of 

 the potatoe, and corrupts the vegetable entirely. The skin 

 of the diseased potatoe comes off easily ; the , flesh cracks 

 tinder the knife : a flatulent liquid drips from the potatoe ; a 

 musty, and presently an animal smell, analogous to the smell 

 of mushrooms recently cut, manifests itself, and occasions 

 considerable nausea. * * * 



The evil being traced to its source, the cultivator must 

 direct all his attention to the destruction of the fungus, or 

 mushroom, for it is unfortunately but too true that all the 

 parasites of this genus once introduced into a country, remain 

 there and propagate. This year the epidemic has been gen- 

 eral ; the germ exists every where : millions upon millions of 

 propagules, if their numbers are not diminished this year, 

 will next year attack the plants, and then it will be more 

 difficult to eradicate the scourge. 



It is essential to adopt the following precaution : 



When the leaves are decidedly spoilt, cut down the vines 

 forthwith, and burn them on the spot, instead of taking them 

 away. 



When certain varieties or certain localities are free from 

 the scourge at the time of the harvest, it is always prudent to 



