ON GENERATION. 189 



opened, and found it perfect : the yelk surrounded by the white, 

 the chalazse attached on either side, and a small cavity in the 

 blunt end ; there was also a cicatricula or macula alba present ; 

 the shell was thick, hard, and strong; and having taken off the 

 top, I had it formed into a cup, in the same way as ostrichs' eggs 

 are commonly fashioned. This egg was somewhat less than 

 that of an ostrich, and, as I have said, perfect in all respects. 

 Undoubtedly, however, it was a sort of accidental egg, and, by 

 reason of the absence of the male, unfruitful. I predicated the 

 death of the cassowary as likely to happen soon when she began 

 laying, moved to do so by what Aristotle says : x "Birds become 

 diseased and die unless they produce fruitful eggs." And my 

 prediction came true not long afterwards. On opening the body 

 of the cassowary, I discovered an imperfect and putrid egg in 

 the upper part of the uterus, as the cause of its untimely death, 

 just as I had found the same thing in the parrot, and other in- 

 stances besides. 



Many birds, consequently, the more salacious they are, the 

 more fruitful are they ; and occasionally, when abundantly fed, 

 or from some other cause, they will even lay eggs without the 

 access of the male. It rarely happens, however, that the eggs 

 so produced are either perfected or laid; the birds are commonly 

 soon seized with serious disorders, and at length die. The 

 common fowl nevertheless not only conceives eggs, but lays 

 them, quite perfect in appearance too; but they are always wind 

 eggs, and incapable of producing a chick. In like manner 

 many insects, among the number silkworms and butterflies, con- 

 ceive eggs and lay them, without the access of the male, but 

 they are still adventitious and barren. Fishes also do the 

 same. 



It is of the same significance in these animals when they con- 

 ceive eggs, as it is in young women when their uterus grows hot, 

 their menses flow, and their bosoms swell in a word, when they 

 become marriageable ; and who, if they continue too long un- 

 wedded, are seized with serious symptoms hysterics, furor 

 uterinus, &c. or fall into a cachectic state, and distemperatures 

 of various kinds. All animals, indeed, grow savage when in 

 heat, and unless they are suffered to enjoy one another, become 



1 Gen. Anim. lib. iii. 



