68 FIFTH ANNUAL REPOKT 



that treatment wliich will cause the vine to regain its normal vigor, he 

 will see no more of riiylloxera — a most undoubted truism! I am the 

 last to deny that meteorological conditions accelerate or retard the 

 multiplication of plant-lice, as they do of so many other insects; but I 

 see no reason for presupposing a diseased condition of the plant first 

 attacked by them, when, as every entomologist knows, they can flour- 

 ish only on living vegetation, which they forsake when its life has been 

 sapped. Conditions may be favorable to the increase of the plant' 

 lice on our hops, of Cotton-worms, of the Army-worm, and of a thou- 

 sand well-known insect pests; yet no one doubts that if by increased 

 effort we, in some way or other, prevent or destroy these insects, we 

 efi"ectualiy overcome the (to us) unfavorable conditions, and our plants 

 thrive. 



Whenever abundant enough to attract attention, these plant-lice 

 have already brought the infested plants into a state of disease, audit 

 is this fact which blinds so many persons, and makes them so ready to 

 believe that it was the diseased condition which attracted, or, as some 

 more ignorantly put it, " produced," the lice. A2)\id e, I repeat, (Rep. 

 3 p. 87), must always be the cause rather than the elfact of disease. 



1 shall simply add in this connection, as strengthening the position 

 of those who consider Phylloxera the true cause of the mischief, that 

 I never yet found root-lice so abundant as on some California vines 

 belonging to Mr. G. Gill, and which were unusually well cared for and 

 manured. 



Other persons, again, have, as might have been expected, insisted 

 that the European insect is not an importation from America, and 

 argued that it may either be a distinct species, either indigenous to 

 both continents, or else may even have been imported from Europe 

 to America. To waive unnecessary detail, I may state that such 

 views are based on fallacious grounds, and that, setting aside theory^ 

 and weighing the undeniable facts, the evidence gives overwhelming 

 force to the oppoite view — that the insect is a native American, and 

 was originally unknown in Europe;* and indeed the views expressed 

 in my last report were adopted by M. Plumeau and others, at the 

 recent organization of the French Society for the Advancement of 

 Science, when the Phylloxera occupied much attention. 



»M. L.L:ilim;in, of Bm-deaux, is, perhaps, the most voUimiunus and influential writer who has 

 espoused the, last-mentio.ied doctrines, in opposition to Lichtenstein, Planchon, myself and others 

 (Annales de la Soc. d'Arjr. da Dep. de la Girondc; Jour, de Viticulture Pratique; La Gironde; La Pro- 

 vence, etc.). Assuming that the insect has always existed in both hemispheres, he quotes M. E. 

 Nourrigit, the President of the Cowurc of Lmiel, as proving that it played havoc in Germany from 

 1730 to 177(5 There is no proof whatever that the disease which attacked vines in Germ my during that 

 epoch, and which Hk>.' wise ailVcted the Mulberry and other fruit trees, bears any relation to the Phyl- 

 loxera disease in question. The article of M. Nourrigat, referred to, flrst appeared in the Journal de 

 Lunel, of March '28rh, 1S71, and describes a disease which, first noticed in Austria, along the Dan- 

 ube, desolated Moravia, Hungary and Germany, and Anally penetrated into Alsace; hut from the 

 symptoms given, it h,is plainly no connection whatever with Phylloxera. M. Laliman, to support his 

 views, ventures a theory so visionary and untenable as to presuppose the existence, from time imme- 

 morial, of the Phylloxera on trees and plants, whose disappearance and eradication have caused it, as 

 he believes, to attack the Vine. 1 presume he was led to such theories by the fact that a certain roo(^ 



