352 



DISEASES 



Sect. XIV. 3.2. 



defended by 



and the larger branches of the pulmonary arteries, are 



thefe brlftles, which are perhaps only beginning to appear on the 



1 



leaf-ftalks of the plum, but which may increafe in the proo-reffion 



ion 



of time; as all the works of nature may be approaching to o-reater 

 perfection, as mentioned more at large in No. 2. of the laft Sedi 

 of this work. 



Fourthly. The means of deftroying an infed fo extenfively inju 

 rious' not only to gardens and hot-houfes, but to half the veo-etabl 



world, would be indeed a valuable difc 



If the eggs exift 



on 



the young buds, as Dr. Richardfon affirms, feme application to thefe 

 before they are hatched, which might difTolve their fliells, as by very 

 dilute marine acid inje6led on them ; or by fome adhefive material 



which might invifcate them as foon as th 



ey 



hatched, wheth 



they appear firft in their larva ftate, like minute caterpillars, or in th 

 form of the parent aphis, as foap-fuds injeded on the twigs before th 

 leaves begin to unfold ; or perhaps by rubbing them with oil or o-lu 

 by means of a fponge, or a painter's brufh ; but ej 



perim 



alone 



* 



1 determine the cfFed of thefe applications, both on. the infed and 

 the tree. 



Lime water alone will not readily deflroy the aphis, as I obferved 



by immerfing leaves with aphifes on them ; which crept up the 

 leaves, and thus efcaped. But 'if pot-afh, or fixed alkali, be mixed 

 with lime, the folution becomes fo cauftic as to deftroy many infeds 



without injuring the foliage of 

 may credit M. SocolofF, who in th 



or the ftems of wheat, if 



fad 



of 



Academy 



Peterfbnrgh, Vol.V. aflerts, that he added three parts of quick 

 newly made to two parts of a faturated folution of fixed alkali in wa- 



!, and 



ter ; which poured on the 



d deflroyed the earth-worm 



or th 



of wh 



fprinkled on the leaves of trees deftroyed the caterpillars, but did 



injure, or much injure the foliage of trees, 



plants. 



Tar water has lately been faid to deftroy flngs, whitp fnails with- 

 out 



\ 



