SECT. XXXIX. 10. 2. GENERATION. 431 



tionsfrom the new powers it has acquired, fo as to form a leaf 

 or lungs either at its fummit in the axilla of the parent leaf, or in 

 any other part of its length ; and alfo to form radicles below, 

 or from any amputated part. 



This new caudex gemmae is proved to commence its forma- 

 tion in feveral places at the fame time from the triple caudex of 

 the bud of a tree, which has been twice fucceflively ingrafted, 

 which we have called a triple mule; but as the new vegetable 

 confifts in general of a combination of parts derived from one 

 parent, it much more accurately refembles that parent in its 

 form, growth, and difeafes, than the progeny from fexual or 

 feminal generation. The fame circumftances occur to the vege- 

 tables, which poffcfs (hort and flat caudexes, which exiit be- 

 tween the radicles and the root-leaves, as in the bulbs of tulips 

 and onions ; which might poilibly be ingrafted on each other likv; 

 the buds of different trees, and form curious mule bulbs. 



This lateral or folitary mode of propagation belongs likewife 

 to the polypus of our ditches, and to the hydra ftentorea, and 

 probably to many other infects. 



2. There is alfo a folitary internal mode of generation, which 

 occurs in the viviparous productions of the aphis, which are 

 known to proceed for eight or nine fucceflive generations with- 

 out the congrefs of fexes ; but what is extraordinary, a con- 

 grefs of fexes appears to be neceffary in their production of an 

 oviparous p r ogeny in the autumn for the prefervation of the fpe- 

 cies during winter ; whence it would feem, that folitary genera- 

 tion always produces a viviparous offspring. For the more par- 

 ticular hillory of this wonderful and important infect fee Phyt- 

 ologia, Seel. IX. and XIV. To which may be added, that a 

 fimilar internal folitary mode of reproduction probably obtains 

 in the tenia, or tape- worm, of the intellines, which afflicts va- 

 riety of animals, and of the aftinea, or fea-anemone, and of the 

 volvox, as defcribed in the Syftema Nature of Linnseus. 



The effential difference between the folitary lateral generation 

 and the folitary internal generation feems to confiit in this ; 

 that in the former there are many glands, which fecrete or pro- 

 duce the fibrils with formative appetencies ; and many other 

 glands, which fecrete or produce the molecules with formative 

 aptitudes or propenfities ; and that thefe numerous fecretioris are 

 mixed together and combine in one large receptacle beneath the 

 cuticle of trees, and of fome infects, and there combining gener- 

 ate the organized particles, which conflitute the rudiment of 

 the new embryon, producing many of the effential parts of it at 

 the fame time ; whereas in the latter, there probably exifts bur 

 one fet of glands, which fecrete the fibrils with formative appe- 

 tencies ; 



