M. de Saint-Hilaire on Didelphis Virginiana. 403 



suming a tone of confidence and dictatorship, in a science, wherein 

 those, who know the most, confess they know the least ; or by ar- 

 guing upon trifles with a captious and disputatious spirit. No; the 

 true Naturalist is he who studies much, and who writes little. He, 

 who after patient investigation, brings to the discussion of contrary 

 opinions, a liberal, a candid, and a gentlemanly spirit ; more anxious 

 to elicit truth, than ambitious of holding up his little discove- 

 ries. It is to men whose minds have been thus stored, and whose 

 feelings are thus regulated, that the world is indebted for the Sys- 

 tema Naturae, the Regne Animal, and the Horae Entomologicae. 

 It is to such examples we must look as guides ; relying upon this, 

 that however the generality of mankind may be struck by a display 

 of words, the great body of Naturalists, (who alone can confer the 

 laurel wreath of fame) will never be persuaded to take " assertion 

 for proof, obscurity for depth, or perplexity for argument." 



I remain. Gentlemen, 

 &c. &c. 



William Swainson. 



Art. XLIX. On the vestiges of a placental Organization, 

 and of an umbilicus^ discovered in a very small Foetus of 

 the Didelphis Virginiana. By M. E. Geoff roy de 

 Saint-Hilaire.* 



Since the publication of my work on the generation of marsupial 

 animals, I have ascertained some new facts which singularly mo- 

 dify certain assertions concerning the developement of marsupial 

 foetuses that I made on the authority of others. I am indebted 

 for this acquisition to our learned Botanist M. Turpin, who had 

 no sooner heard of my work, than he had the goodness to furnish 

 me with the foetuses of the Didelphis Virginiana^ perfectly pre- 

 served in spirits. They were given to him by Dr. Barton, as he 

 was about to quit America, who informed him that he had taken 



* From the Annales des Sciences Naturelles. 

 2 n 2 



