THE GRAPE VINE. 123 



spread of the disease from one vine to another, the wingless 

 pucerons may suffice for this, as, grouped in great numbers about 

 the lower part of unhealthy vine-stems, they might easily attack 

 the vines nearest them, even if they be healthy. It may be asked, 

 in what manner these insects manage to travel from one vine- 

 stock to another, and how they contrive to reach the fibrous roots 

 of the newly-attacked stocks ? Do they burrow under the soil, 

 or do they not rather travel along the surface of the earth under 

 cover of the darkness and coolness of night, and then, traversing 

 the fissures in the bark, arrive in this manner at the extremities 

 of the roots ? This conjecture is a probable one, and the follow- 

 ing experiment supports it : 



" In a case 1 yard long I placed some garden-soil from Mont- 

 pelier, a place entirely free from the Phylloxera. In this earth I 

 carefully laid some pieces of vine-cane infested with wingless 

 pucerons. I placed a hand-glass over each cane, and slightly 

 raised the glass on one side in order to allow the insect to creep 

 out. At three centimetres' distance from the pieces of cane I 

 put some fragments of root from a healthy vine, on which I 

 had made fresh wounds. In twelve hours the following results 

 were obtained : Three pucerons had found their way from one 

 of the vine-canes to the nearest piece of vine-root. Some days 

 after, twenty young pucerons occupied the same fragment. A 

 few insects were to be found on the other fragments. One piece 

 of root had attracted none, but the vine-cane nearest to it had 

 very few insects upon it which were capable of changing their 

 places. 



" A similar experiment has been made by M. Frederic Leydier 

 at the farm of Lancieux, near Sigondas (a part of the country 

 already infested by the Phylloxera), and by another person near 

 Sorgues. The results of these experiments have not been satis- 

 factory ; but this does not prove that, under other conditions, 

 or with a greater amount of perseverance, they might not have 

 been successful. It is fortunate that this new enemy to the vine 

 attacks it (in the first instance) at the base of the stem, and not 

 underground at the fibres. As it is, a thorough dressing of the 

 bottom of the stem with coal-tar will probably prove an insur- 

 mountable obstacle to the progress of this destructive insect ; but 

 were the case otherwise, it would be very difficult to get down 

 deep enough to reach an enemy so well protected by the depth of 

 the soil." 



