C 2 °4 3 



its being neceffary to hide themfelves in fuch holes and caverns as 

 may not only elude the fearch of man, but of every other animal 

 which might prey upon them j. it is not therefore by any com- 

 mon accident that they are ever difcovered in a ftate of tor- 

 pidity. 



Since the ftudy of natural hiftory, however, hath become more 

 general, proofs of this fact are frequently communicated, as may" 

 appear in the Britifh Zoology K 



That it may not be faid, however, I do not refer to any in— 

 ftance which deferves credit, if properly lifted, I beg leave to cite 

 the letter from Mr. Achard to Mr. Collinfon, printed in the Phi- 

 lofophical Tranfactions k , from whence it feems to be a mod ir- 

 refragable fd.dc, that fwallows 1 are annually difcovered in a torpid, 

 ftate on the banks of the Rhine. I fhall alfo refer to Dr. Birch's 

 Hiftary of the Royal Society m , where it is ftated, that the cele- 

 brated Harvey difllcted fome, which were found in the winter, 

 under water, and in which he could not obferve any circulation 

 of the blood, 



. -Afluming it, therefore, from thefe facts, that fwallows have- 

 been found in fuch a ftate, I would alk the partifans of migration, 



5 See vol. II. p. 250. Brit. Zool. ill. p. 13, 14. As alfo Mr. Pen- 

 nant's Tour in Scotland, p. 199. 



k I 7^3? P* IOI « 



1 " Swallows or martins,'* are Mr. Achard's words, which I the rather 

 mention, becaufe Mr. Collinfon complains that the fpecies is not fpe- 

 cificd. 



Mr. Collinfon himfelf had endeavoured to prove, that fand martins 

 are not torpid, Phil. Tranf. 1760, p. 109. and concludes his letter, by 

 fuppoling that all the fwallow tribe migrates, therefore the fwift is the 

 only fpecies remaining ; for his friend Mr. Achard Ihews to demonftra- 

 tion, that fwallows or martins are torpid ; he does not, indeed, precifely 

 ftate which of them. 



vol. iv. p. 537. 



whether 



