458 ON GENERATION. 



and because the identity is in conformity with reason. For 

 the vegetal primordium which lives potentially is also an ani. 

 mal potentially. Nor can the distinction which Aristotle 1 

 made between the egg and the worm be admitted : for he de- 

 fines an egg to be that " from part of which an animal is pro- 

 duced ; whilst that," he says elsewhere, 2 " which is totally 

 changed, and which does not produce an animal from a part 

 only, is a worm." These bodies, however, agree in this, that 

 they are both inanimate births, and only animals potentially ; 

 both consequently are eggs. 



And then Aristotle himself, whilst he speaks of worms in 

 one place, designates them by the name of eggs in another. 3 

 Treating of the locust, he says, 4 " its eggs become spoiled in 

 autumn when the season is wet ;" and again, speaking of the 

 grasshopper, he has these words, " when the little worm 

 has grown in the earth it becomes a matrix of grasshoppers 

 (tettigometra) ;" and immediately afterwards, " the females are 

 sweeter after coitus, for then they are full of white eggs." 



In this very place, indeed, where he distinguishes between 

 an egg and a worm, he adds: 5 "but the whole of this tribe 

 of worms, when they have come to their full size, are changed 

 in some sort into eggs ; for their shell or covering hardens, 

 and they become motionless for a season, a circumstance that 

 is plainly to be seen in the vermiculi of bees and wasps, and 

 also in caterpillars." Every one indeed may observe that the 

 primordia of spiders, silkworms, and the like, are not less to 

 be accounted eggs than those of the Crustacea and mollusca, 

 and almost all fishes, which are not actually animals, but are 

 potentially possessed of the faculty of producing them. Since, 

 then, those creatures that produce actually are called vivipa- 

 rous, and those that produce potentially either pass without 

 any general distinguishing title or are called oviparous and parti- 

 cularly as such productions are vegetal primordia, analogous to 

 the seeds of plants, which true eggs must needs be held to be, 

 the conclusion is, that all animals are either viviparous or 

 oviparous. 



But as there are many species of oviparous animals, so must 



1 De Gen. Anim. lib. iii, cap. 9. 4 Hist. Anim. lib. v, cap. 30. 



2 Hist. Anim. lib. i, cap. 5. * De Gen. Anim. lib. iii, cap. 9. 



3 Ib. lib. v, cap. 29. 



