2i8 Mayow 



out to the placenta, may be there impregnated with 

 a portion of nutritious juice charged with aerial 

 matter ; and that it should return thence, with never 

 interrupted motion to the foetus, for the purposes at 

 once of nutriment and of respiration. 



For indeed it is probable that if arterial blood, 

 which is imbued with nitro-aerial spirit, came to the 

 heart instead of venous, there would be no need at all 

 for respiration. And this seems to be confirmed by 

 the fact that when arterial blood, in what is now a 

 well-known experiment, is transmitted from one dog 

 to another, the dog to which the blood is transferred, 

 although previously panting and breathing violently, 

 yet, after receiving the arterial blood, seems scarcely 

 to breathe at all. 



OF THE RESPIRA TION OF THE CHICK IN THE EGG 



Thus far of respiration in the uterus ; it remains for 

 us to discuss briefly the respiration of the chick in the 

 Qgg. For there can be no doubt that the want of 

 respiration in the egg also is supplied from another 

 source. It is in fact our opinion that the chick in the 

 Qgg respires through the umbilicus very much in the 

 same way as the child in the uterus. For when I 

 contemplate the really marvellous and complicated 

 network of the umbilical arteries in the incubated 

 egg^ and then consider that none of the things 

 essential to animal life are wanting in the egg^ except 

 respiration only, assuredly I can arrive at no other 

 conclusion than that the aforesaid vessels are formed 

 to compensate for the lack of respiration. 



Wherefore, let us now inquire how the umbilicus 

 in the egg supplies the place of respiration. In 



