174 EMBRYOLOGY IN THE SEVENTEENTH [pt. ii 



though Hartsoeker afterwards claimed that he had seen them as 

 early as 1674, but had not had sufficient confidence to publish his 

 results. There is a reference to this in the letters of Sir Thomas 

 Browne, who, writing to his son, Dr Edward Browne, on December 9, 

 1679, said, "I sawe the last transactions, or philosophicall col- 

 lections, of the Royal Society. Here are some things remarkable, as 

 Lewenhoecks finding such a vast number of little animals in the melt 

 of a cod, or the liquor which runnes from it ; as also in a pike ; and 

 computeth that they much exceed the number of men upon the whole 

 earth at one time, though hee computes that there may bee thirteen 

 thousand millions of men upon the whole earth, which is very many. 

 It may bee worth your reading". 



At the same time as these events were taking place, Robert Boyle, 

 at Oxford and London, was engaged in carrying out those experi- 

 ments in chemistry which led him before long to write his Sceptical 

 Chymist. It is not generally known that in this work, which appeared 

 in 1680, and which set the key for the whole spirit of subsequent 

 physico-chemical research, Boyle has a reference to embryology, and, 

 curiously enough, in connection with a point which, although it is 

 easily seen to be of the highest importance, has been quite overlooked 

 by the commentators upon him. One of the main things he was 

 trying to urge was that, until some system could be proposed which 

 would give a means of quantitative estimation of the constituents of 

 a mixture, no further progress would be made. He was asking, in 

 fact, that chemistry should become an exact science, and his demand 

 is only veiled by the unfamiliarity of his language. His preference 

 for the "mechanical or corpuscularian" philosophy was mainly due 

 to his realisation that, unless chemistry was going to start measuring 

 something, it might as well languish in the obscurity to which 

 Harvey would have willingly relegated it. Thus he says, "But I 

 should perchance forgive the Hypothesis I have been all this time 

 examining (that of the alchemists), if, though it reaches but to a 

 very little part of the world, it did at least give us a satisfactory account 

 of those things which 'tis said to teach. But I find not that it gives 

 us any other than a very imperfect information even about mixt 

 bodies themselves; for how will the knowledge of the Tria Prima 

 discover to us the reason why the Loadstone drawes a Needle, and 

 disposes it to respect the Poles, and yet seldom precisely points at 

 them? how will this hypothesis teach us how a Chick is formed 



