94. Dr. Latruam’s Effay on the Trachee or Windpipes of Birds, 
dive with fuch facility as they are known todo. The Wild Swan, 
in which we obferve a great elongation added to a peculiar curvature 
of the windpipe, is able to hold its head for a length of time under 
water in fearch of food; but we have no authority for faying whether 
it can do foa longer time than the Tame Swan, in which no fuch pecu- 
liarity is feen. Befides, the common Crane, and others of the Ardea 
genus, which have not in their power even to:{wim, are endowed 
with a much greater elongation and curvature of the windpipe 
than the Wild Swan. In refpeé&t to what afliftance fuch a conftruc- 
tion of parts as abovefaid may afford to the tone of voice, 1 will not 
venture here to afhrm ; yet it cannot be denied that fome birds are 
able to utter very loud founds without fuch aid—witnefs the Cock, 
Peacock, and others*. We fee Nature’s operations and admire them 
in courfe, yet cannot always comprehend the utility of her works ; 
and this feems one of her defigns concerning which we are not at 
all clear. It, too, mutt be confeffed, that the whole we have been 
able to obtain by our fcrutiny into this fubject is, the fecurity ofa 
mark of diftinétion, in refpeét to feveral {pecies concerning which 
we have been more or lefs in a {tate of uncertainty. 
I am aware likewife that anatomifts have done much in regard to 
the difcovery of fex, by obferving the #jfficles of the male, which 
confit of two whitifh glandular bodies placed juft below the lungs, 
clofe to the back-bone, and the ovaries, or clufters of eggs, fituated in ~ 
the fame place, in the female. It is true that the /ex may, by at 
* How far the difcovery of the difperfion of air-veffels, which are found among tlre 
flefhy parts of birds, pervading more or lefs even the Jones themfelves, and communi- 
cating with the lungs, may contribute to their being able to dive and ftay fo long under 
water, or whether this circumftance may affift in voice, fong, or flight, is not for us here 
to determine. ‘The matter is certainly worth further enquiry, but cannot make any part 
of this eflay, further than to recommend the perufal of a Treatife on the fubje& by our 
late friend Mr. John Hunter, in the Philofophical TranfaQtions.—See vol. Ixiv. p. 205. 
tending 
