Hlatorij and Pnigrcss ofCumpartt/'/ir Aiiutuvii/. ^^ 



the bear, the inequalities on the surface of those of the calf, and 

 of the foetus and infant of the human subject, thus recording 

 the fact, which is connected with the manner of development in 

 distinct tubular conoids or lobules, which are eventually united, 

 - His researches on the teeth, which come next, shew that he 

 studied the structure and formation of these bodies attentively. 

 It is interesting to observe, that, in describing the formation of 

 the teeth in the foetus, he recognises the fact, that the dentife- 

 rous sacs contain not only the temporary but the permanent 

 set ; and so accurate is his observation, that he remarks, that 

 the only difference between the two ranges is, that the ca- 

 nine teeth correspond with the large incisors of the second range. 

 He describes accurately die formation of the enamel, and re- 

 commends the anatomist to study it in the foetus and young 

 buck, if he has not opportunities of observing the process in 

 the human foetus. The internal canals or nutritious tubes, and 

 their vascular pulp or sac^ he describes from the human body, 

 the ram, and the ox, in which he allows that the process of 

 growth is most distinct. The whole description is most accu- 

 rate, and deserves the attentive perusal of the anatomical reader. 



In a subsequent account of the bones, he describes the osteo- 

 logy of the monkey with minuteness and accuracy, and com- 

 pares it with that of the human subject. The object of this es- 

 say is not quite so laudable as that of his other works ; and I 

 regret to say, that his principal purpose appears to have been to 

 establish the fact, that the osteology of Galen is not derived from 

 the human skeleton. He has the courage in this treatise, how- 

 ever, to reject the human allmitois. 



In his chapter on the vena nzygos, or vena sine pari, Eustachio 

 announces a discovery, which alone is sufficient to confer im- 

 mortality. The distribution of this vein he had studied in se- 

 veral animals ; and, in observing its structure and relations in 

 the carcass of a horse, he recognised, on the left side of the ver- 

 tebral column, a white vessel full of watery fluid, connected 

 above with the jugular vein, and with its lower end not yet as- 

 certained, and forming the large central trunk of the lacteals, 

 which was afterwards denominated the thoracic duct. This 

 memorable fact is so interesting, that I cannot refrain from 

 giving the description of the author. 



