SECT. 3] AND EIGHTEENTH CENTURIES 163 



all salt, but in older animals, when I distilled it in an alembic, I 

 seemed to observe a little volatile salt at the small end [in capitello]. 

 Coagulations attempted by acids happened differently in respect of 

 the different humours. For when I poured a decoction of alumina 

 into the liquor of the cow's amnios it exhibited a few rather fine 

 coagulations but they were clearly white. The allantoic juice, how- 

 ever, was precipitated like urine. Spirits of vitriol and vinegar 

 brought about less results than alumina in each case. Spontaneous 

 concretions I found also in the later months; these I discovered in 

 both places. They are more frequent and larger, however, within 

 the allantoic membrane." 



From the above excerpt, which contains the account of all that 

 Needham did on the chemical composition of the embryonic liquids, 

 it can be seen that he treated the whole matter more dynamically 

 than Browne. He was the first to describe the solid bodies in the 

 amniotic fluid (see Jenkinson) and his chemical experimentation was 

 all pioneer work. 



His book has other merits, however. In the first chapter, he refutes 

 the theory which Everard had propounded, that the uterine milk was 

 identical with the contents of the thoracic duct, conveyed by lym- 

 phatic vessels to the uterus from the lac teals of Aselli, instead of 

 elsewhere, and he shows that arteries must be the vessels bringing 

 the material to the womb. The second chapter deals with the placenta 

 "where he giveth a particular account of the double Placenta or 

 Cake, to be found in Rabbets, Hares, Mice, Moles, etc., and examines 

 the learned Dr Wharton's doctrine, assigning a double placenta to at 

 least all the viviparous animals, so as one half of it belongs to the 

 Uterus, the other to the Chorion, shewing how far this is true, and 

 declaring the variety of these Phaenomena. Where do occur many 

 uncommon observations concerning the difference of Milk [uterine] 

 in ruminating and other animals, the various degrees of thickness of 

 the uterin liquor in oviparous and viviparous creatures". He de- 

 scribes the human placenta very correctly indeed. "The use of the 

 placenta is known to be to serve for conveighing the aliment to the 

 foetus. The difficulty is only about the manner. Here are examined 

 three opinions, of Curvey, Everhard, and Harvey. The two former 

 do hold that the foetus is nourished only from the Amnion by the 

 mouth ; yet with this difference, that Curvey will have it fed by the 

 mouth when it is perfect, but whilst it is yet imperfect, by filtration 



