Séance du 17 Novembre 1920 97 



point oui Ihal liis dcscriplion of llie [raclical wall is noi 

 COI reel. Il is noi hclwcen the Irne membrane and the 

 iiìliiiìii l)ul in liie outer sheath thai IJie hlood is seen lo 

 How. XeviMiheiess one faci remains. In insects gene- 

 lally Mìe li'aeheal slicaths are so made Ihal Ihev can, in 

 some paiis ol" the body, allow blood lo enter and, under 

 certain circumstances, be used for the circulation ol" 

 this li([uid. 



Kven il" usinii; the im[)errect methods ol' his day 

 Bi.ANCHAHD made some mistaUes, at any rale he had an 

 inkling of the phenomena we have described. 



For me personnaliy who as a youui; student in liS()9 

 learnt t.) dissect Insects in the laboralory ol' the 

 '•Muséunì", then under Hlancuauo, thei'e is much real 

 ])leasure in seeing; 0(1 years later the theory ol' the })eri- 

 tracheal circulation ol' the blood partly rehabilitated and 

 conlii-med. ( 1 ), 



La Luciole, Aix en Provence. June 191U. 



1. LowNi-: (!<S93-9.')) p. 3()7 speakin,i( of the relalit)ns 

 between Hie traeliciie and the l)lüod sinuses says: — "Tlie 

 air-sacs may be described, therefore, ai beinj^ surrounded 

 by narrow l)Iood-sinuses. In this sense there is a true peri- 

 tracheal eirculation.. . The larger cylindrical trunks also 



lie in the walls of blood-sinuses Clanchard's theory 



of an intra-tracheal circulation was the result of a miscon- 

 ception as to the structure of the tracheae, and is, of course, 

 not possible, but in the sense explained above the circulation 

 is essentially peritracheal.» 



