VOL. II.] PHILOSOPHICAL TRANSACTIONS. 271 



An Account of tivo Boohs. N" 38, p. 750. 



I. R. (le Graaf, M. D. de Virorum Organis Generationi Inservientibus, Ludg. 

 Bat. 1(568, l2mo. 



This treatise was promised by the author in a printed epistle of his, of which 

 we gave an account in N° 34, p. 241. There being at that time published a 

 Prodromus of J. Van Home, wherein it was suspected that the observations of 

 de Graaf were much the same with his upon this subject ; we do now, upon the 

 perusal of this book, find chiefly these considerable differences between them : 



Van Home makes the spermatic artery in man to go to the testicles in a 

 winding, but De Graaf in a straight direction. The former affirms, that the 

 vasa deferentia have no communication with the vesiculae seminales ; but the 

 latter maintains and demonstrates that there is so great a communication be- 

 tween them, " ut semen dum a testibus per vasa deferentia affluens in urethram 

 " effluere nequit, propter carunculam clausam ; necessario influat in vesiculas, 

 " in iisque pro futuro coitu reservetur." The former is of opinion, " triplicem 

 " esse materiam seminis ;" but De Graaf will have only one, answering the 

 arguments of both Van Home and Dr. Wharton to prove that triplicity. 



But what De Graaf much insists on in this book is, to show what is the true 

 substance of the testicles, and to vindicate the discovery thereof to himself, 

 affirming positively that no man before him ever knew tHe truth of it.* For 

 the making out of which, he first denies that the testes are glandulous or pulta- 

 ceous ; and then affirms that their substance is nothing else but a '* Congeries 

 " minutissimorum vasculorum semen conficientium, quae si absque ruptione 

 *' dissoluta sibi invicem adnectereiitur, facile viginti ulnarum longitudinem ex- 

 ** cederent." Which he affirms he can prove by ocular demonstration. 



He then shows how the seminal vessels pass " e testibus ad epididymides," 

 viz. not by one tmnk (as Dr. Highmore-}- thinks) but by 6 or 7 small ducts; 

 assigning the cause why Dr. Highmore did not see them. 



Farther he examines, " An semen in testibus conficiatur ; utrum ex sanguine 

 " vel ex lympha ? quomodo elaboretur, crassescat, lactescat : qua via a testibus 

 " ad urethram excurrat." 



He also endeavours to prove, '* Vesiculas seminales ordinatas esse non seminis 

 " generationi, sed ejus receptioni et asservationi." 



* See Dr. Clarck's letter. No. 35. 



t Nathaniel Highmore practised at Oxford in the middle of the 17th century, and acquired a con- 

 siderable reputation by his medical and anatomical writings, viz. by his Corp. Hum. Disquisitio 

 Anatomica, by his History of Generation, and by his Exercitationes de Passione Hyst. deque Hypo- 

 chondriaca AfFectione. But Haller finds fault with the descriptions given in the first of these anato- 

 raical works, and says that most of the plates are copied from Vesalius. 



