Séance du 17 Novembre 1920 



one of Ilio image seen in a frog s fool willi lliis dill'er- 

 ence that the corpuscles are less numerous and move 

 more slowly. Return currents were not observed. Oa 

 the other hand I observed slight extravasations local- 

 ised al a lew points. 



Al the beginning of the uidblding process, the 

 wings ol Empusa show a basal jiortion, swollen and 

 slighlly diaphanous, while the apical portion is llalten- 

 ed. The boundary of the two regions is a sinuous 

 line which gradually vanishes as Ihe unfolding pro- 

 ceeds. This a[)pearance can be explained thanks to 

 extravasalions. While a part of Ihe blood ciiculates 

 within the channels, Ihal porlion of the mass which 

 has been driven oui also ])rogresses owing to Ihe 

 successive heals. Inlillraling Ih.e interstitial lissue 

 behveen Ihe wing layers, this [jortion se[)aral(>s the 

 Iwo layers and assists Iheir unfolding. 



This inlillialion of the interstitial tissue is ob- 

 viously only lenii)oiary. When fully unfolded the 

 wings naturally lewd to Hallen. A few hours is 

 suliicient for them lo lake u\) Iheir linai appearance. 

 The mechanism by which this llatlening lakes 

 |)lace has iiol been fully obserxed. ll is nevertheless 

 jusliliable to supi)0sc' lluil the cenli'ifugal movement 

 is followed by a reverse How especially along the edges. 

 The function of this return flow would be to assist 

 in the reabsorption of the blood. 



I cannol tell whether blood circulation continues 

 in the wings of Empusa when Ihey are fully unfolded 

 or whether the greater opacily of the wing merely 

 conceals it. Experiments made on imagos several 

 days (ild have given so far only negative lesults. 



