Aristotle's History of Animals. 73 



incomplete metamorphoses, in which the larva difFers from the 

 perfect insect only in the absence of wings, and only undergoes 

 a single ti-ansformation. He speaks of the insects which occur 

 in snow ; and, in short, enters into a multitude of very interest- 

 ing and perfectly accurate details. He admits spontaneous ge- 

 neration, however, in these animals, and thinks, that, when the 

 constituent elements present themselves in the necessary propor- 

 tions, and in favourable circumstances, they are capable of giving 

 rise to living beings ; but, at this period, such an error was al- 

 most inevitable, and it was not until the invention of the micro- 

 scope that the truth could be known. He speaks of the econo- 

 my of bees, and says that some persons consider the Jdng as a 

 female. He describes the kind of cell constructed for these 

 privileged individuals, which shews that he had observed the in- 

 terior of their hives, although he certainly could not have had 

 the use of glass, which gi-eatly facilitates an examination of this 

 kind. He also treats of the domestic economy of wasps, hornets, 

 mason-bees, and drones ; describes the singular covering in 

 which the larva of the Phryganea is enveloped, and speaks of spi- 

 ders whidi carry under their belly the bag which contains their 

 eggs. In speaking of animals of a liigher order, he makes a 

 very accurate distinction between the eggs which have a hard 

 envelope, as those of crocodiles and tortoises, and those with a 

 soft envelope, as in serpents. He says that serpents which bring 

 forth their young alive, have yet eggs, but that these eggs are 

 hatched within them. He was perfectly acquainted with the 

 development of the chick during incubation, describes it day af- 

 ter day, speaks of the heart as the first point that appears, of 

 the veins which afterwards stretch towards the upper and lower 

 parts of the body, and, lastly, of the alantoid membrane which 

 presently envelopes the whole egg. It ought to be remarked, 

 that all these observations were made with the unaided eye, and 

 that the slight errors which may be marked in them depend 

 solely upon the circumstance that Aristotle had no magnifying 

 glasses. He remarks, in speaking of the eggs of fishes, that 

 the alantoid membrane does not exist in them, nor in those of 

 any other animal that respires by branchia?. He admits spon- 

 taneous generation in fishes, as he had done in insects ; and, in 

 Mipport of this opinion, adduces facts which appear conclusive 



