i64 EMBRYOLOGY IN THE SEVENTEENTH [pt. ii 



through all the pores of the body, and by a kind of juxtaposition : but 

 Everhard, supposing a simultaneous formation of all the instruments 

 of nutrition together and at first, and esteeming the mass of bloud 

 by reason of its asperity and eagerness unfit for nutrition, and rather 

 apt to prey upon than feed the parts, maintains, that the liquor is 

 sucked out of the amnion by the mouth, concocted in the stomack, 

 and thence passed into the Milky Vessels even from the beginning. 

 Meantime they both agree in this, that the embryo doth breath but 

 not feed through the umbilicall vessels. This our Author undertakes 

 to disprove; and having asserted the mildness of, at least, many 

 parts of the bloud, and consequently their fitness for nutrition, he 

 defends the Harveyan doctrine of the colliquation of the nourishing 

 juyce by the Arteries and its conveyance to the foetus by the 

 veins." 



In the third chapter Needham gives the first really comparative 

 account of the secondary apparatus of generation, enunciating the 

 rather obvious rule that in any given case the number of membranes 

 exceeds the number of separate humours by one. He affirms that 

 all the humours are nutritive save the allantoic. It had previously 

 been held that all fish eggs were of one humour only, but he points 

 out that a selachian egg has its white and yolk separate. He gives 

 the results of his chemical experiments at this point, and suggests 

 that the noises heard from embryos in utero and in ovo may be due 

 to the presence of air or gas in the amniotic cavity, thus forming a 

 link between Leonardo and Mazin. In his fourth chapter he deals 

 with the umbilical vessels and the urachus, and here he claims priority 

 over Stensen for the discovery of the ductus intestinalis in the chick, 

 referring to Robert Boyle, Robert Willis, Richard Lower and Thomas 

 Millington, to whom, he says, he showed the duct before Stensen 

 published his observations on it. The fifth chapter is concerned with 

 the foramen ovale, and the arterial and venous canals, and with the 

 foetal circulation in general. The sixth is about respiration or "bio- 

 lychnium", and in it Needham writes against the conception of a 

 vital flame, alleging cold-blooded animals, etc., in his favour, but 

 here he takes a retrograde step, for he argues that the use of the lungs 

 is not for respiration but to "comminute the bloud and so render 

 it fit for a due circulation". "The seventh and last chapter contains 

 a direction for the younger Anatomists, of what is to be observed in 

 the dissection of divers animals with young, and first, of what is 



