upon the same, or at least an equal footing. You 
have not seen living Sirens, nor have you dissected 
dead ones. These advantages I have enjoyed ; and, 
in addition to these, I have had the opportunity of 
comparing my observations with those which Dr. 
Schreibers has published in his excellent memoir. 
This memoir you could not have seen when you 
published the two first fasciculi of your Histoiia 
Amphibiorwn. 
But I close this long letter with observing, that 
every naturalist should assume to himself the privi- 
lege of delivering his sentiments with entire freedom^ 
and that science frequently sujBfers as much from an 
excess of reserve as from a prompt, or even ardent, 
decision. If 1 am wrong in my opinion, that the Si- 
rens and Protei are perfect animals, and not mere 
cordyli, it will, at least, be acknowledged, that I 
have founded that opinion upon a greater body of 
facts and observations than were in possession of 
some of those distinguished naturalists, whose theo- 
ry, in regard to these animals, is entirely the oppo- 
site of mine. A few years, — perhaps a few months, — 
will unveil all the remaining difficulties which are 
still attached to this curious subject. In the mean- 
while, be assured of my willingness to meet the 
truth, in whatever light it may be presented to me : 
and permit me to subscribe myself, 
Dear Sir, 
With great respect, 
Your friend, &c. 
BENJAMIN SMITH BARTON. 
Philadelphia^ April l^th^ 1807. 
