156 EMBRYOLOGY IN THE SEVENTEENTH [pt. 11 



answers, and they were of little importance. Janus Orcham took 

 exception to Harvey's finding no seed in the uterus and suggested 

 that it had vaporised like a steam, but his Aristotelian leanings were 

 promptly detected and castigated by Rallius. Matthew Slade, taking 

 the pseudonym of Theodore Aides, published in 1667 his Dissertatio 

 epistolica contra D. G. Harveium, which was, in his own words, "a 

 detection of one or two errors in that golden book on the generation 

 of animals of William Harvey, greatest of physicians and anatomists". 

 The errors were purely anatomical, and ab Angelis defended Harvey 

 against Slade's attack, claiming that the "errors" were not errors 

 at all. A manuscript work of Slade's appears to be extant. 



Harvey's influence was evidently speedily felt by his contemporaries. 

 Strauss soon wrote a rather poor book on the bird's egg in imitation 

 of him. But the best instance is that in 1655, very soon after the 

 publication of Harvey's book, William Langly, "an eminent senator 

 and physician of Dordrecht", made a great many experiments on 

 the development of the hen's egg. Buffon says that he worked in 

 1635, i.e. before Harvey, but this is not the case, for in his observa- 

 tions which were published by Julius Schrader in 1674 the later date 

 is given several times. Langly mentions Harvey more than once, 

 and evidently followed his example in careful observation, for his 

 text is concise and accurate and his drawings very noteworthy. 



Julius Schrader included Langly's work in a composite volume 

 containing a well-arranged epitome of Harvey's book on generation 

 and some observations of his own on the hen's egg. The book was 

 dedicated to Matthew Slade and J. Swammerdam. On the practical 

 side Schrader added nothing memorable to Harvey and Langly, but 

 it is noteworthy that the mammalian embryo was throughout these 

 centuries more popular material than that of the chick. Out of fifty 

 embryologists between Harvey and Haller, the names of Langly, 

 Schrader, Malpighi and Maitre-Jan practically exhaust the list of 

 those who studied the egg of the hen. This rather unfortunate orienta- 

 tion of mind doubtless sprang from the strong influence of medicine, 

 and especially obstetrics, on seventeenth and eighteenth century 

 embryology. 



3-5. Gassendi and Descartes: Atomistic Embryology 



Harvey's death took place in 1657. The following year saw the 

 publication of Pierre Gassendi's Opera Omnia, and thus brought in 



