APHIS. 179 



wet is not so hurtful to them as is generally ima- 

 gined." 



" Though no mode of destroying Aphides will 

 perhaps ever be devised on a large scale in the 

 open air bv artificial means, we can accomplish it 

 most effectually when they infest plants in green- 

 houses and frames, or in any situation in which 



., 



we can envelop them for a certain time in clouds 

 of smoke. Po\vders or liquids, however fatal to 

 Aphides, must ever be ineffectual, from the trouble 

 and difficulty of applying them so that they shall 

 come in contact with those insects, situated as 

 they usually are; but in this respect smoke has 

 every advantage; it penetrates and pervades their 

 inmost recesses. The smoke of common ves^et- 



o 



ables, however powerful, is found to be inadequate 

 to their destruction, and hitherto no other than 

 that of Tobacco is found to be effectual. That, 

 judiciously applied, completely answers the pur- 

 pose, without injuring the plant. It mostly hap- 

 pens, in well managed houses, that a few plants 

 only are infested with Aphides; in such a case 

 the smoking of the whole house is a business of 

 unnecessary expence and trouble; and we would 

 recommend it to persons who have large collec- 

 tions to make use of a box of a commodious form 

 that shall hold about a dozen plants of various 

 sizes, to be used as a sort of hospital, in which the 

 infested plants may be smoaked separately, and 

 the insects more effectually destroyed, because it 



V * * 



may be rendered more perfectly smoke-tight." 



" To prevent the calamities which would in- 

 fallibly result from the accumulated multiplication 



