200 TRANSACTIONS OF THE 



MR. J. A. BAUER'S PHYLLOXERA REMEDY. 



As a general answer to numerous inquiries concerning the probable 

 efficacy of the phylloxera remedy devised by Mr. J. A. Bauer, of San 

 Francisco (viz., the introduction of finely divided quicksilver into 

 the earth around the stock), regarding which several articles have 

 lately appeared in the public press, the following points, based upon 

 the known and observed habits of the insect, are here given in 

 advance of the experiments which it is hoped will be extensively 

 made during the coming season : 



There can be no question as to the efficacy of metallic mercury 

 finely difii"used through the soil in killing the phylloxera or any other 

 small insect remaining within its reach for any length of time. Apart 

 from the experience long had in this respect in the means used for 

 the preservation of various articles, insect collections, etc., from the 

 attacks of small insect depredators, the direct experiments of Mr. 

 Bauer on earth and roots infested with the phylloxera have been 

 entirely conclusive as to the inability of the latter to live more than 

 a few hours in the atmosphere created in a close space, or in earth, at 

 the ordinary temperature, by finely divided mercury. The conclu 

 sion that a soil column of six or eight inches depth, impregnated 

 with the mercurial vapor by intermixture with " blue mass," will 

 effectually prevent the passage through it of the slow-going insect, is 

 therefore fully justified. Many other substances might be used to act 

 similarly in this respect, e. g., gas lime; but none others thus far sug- 

 gested possess the permanency of the mercurial preparation, and the 

 entire innocuousness toward even the most delicate rootlets, unless 

 perhaps in the case of the direct contact of the globules themselves. 

 On this point certainly Mr. Bauer's inspiration has been a most happy 

 one, and while the introduction of mercury into boreholes made in 

 the stem of the vine has long been suggested and found to be use- 

 less, his suggestion is, so far as known, altogether new and certainly 

 original. 



Were it feasible to impregnate the entire soil of a vineyard with the 

 mercurial preparation, the phylloxera, being unable to ascend to the 

 surface, would probably in a few generations be compelled to suc- 

 cumb, as the "winged form" could not then perform its functions 

 toward the renewal of the tribal vigor by sexual reproduction. Since, 

 however, so extended a use of even this very dilute insecticide is 

 hardly practicable on the large scale, it remains to be determined to 

 what extent its use immediately around the trunk of the vine, in the 

 manner proposed by Mr. Bauer, will be likely to serve the purposes 

 of prevention and repression. 



The interposition of obstacles to the passage of the insect along the 

 stock was among the early suggestions of aspirants to the great prize 

 offered by the French Government for the discovery of an effectual 

 remedy. We have among the inventions aiming in that direction 

 even a proposition to incase the stock in a plaster jacket of several 

 inches thickness. It will be surmised that the sagacious insect was 

 not long in discovering a convenient path outside of the lump of 

 plaster toward the coveted roots. 



In the case of Mr. Bauer's plan, however, the descending or ascend- 



