292 The Structure of Colored Blood- Corpuscles. 



of a certain power of resistance in frog's red blood-corpuscles 

 after keeping them a few days on the slide without addition of 

 any reagent, which membrane was particularly obvious when 

 the nucleus made its exit out of the corpuscular mass. 1 

 According to A. Bechamp* and J. Bechamp and Baltus, 3 

 the red blood-corpuscles of mammals, birds and amphibia, pos- 

 sess a distinct membrane which can be thickened by adding a 

 solution of starch to the blood and then becomes more resist- 

 ant to the action of water. 



It has even been supposed that blood-corpuscles had more 

 than a single membrane ; thus Roberts said 4 his observations 

 had led him " to the belief that the envelope of the verte- 

 brate blood-disk is a duplicate membrane ; in other words, 

 that within the outer covering there exists an interior vesicle 

 which encloses the colored contents, and in the ovipara, the 

 nucleus." Bottcher has refuted this notion, 5 and it is charac- 

 terized by Wedl, too, as incorrect ; according to Wedl, when 

 the cortical layer becomes swelled and condensed, the double 

 contour which is seen indicates its thickness — but he is 

 " quite certain that whether it be called membrane or not, it 

 is not simply an artificial product." 6 Zankester, in his con- 

 clusions regarding the vertebrate red blood-corpuscle, says : 

 its surface is differentiated somewhat from the underlying 

 material, and forms a pellicle or membrane of great tenuity, 

 not distinguishable with the highest powers (whilst the 

 corpuscle is normal and living), and having no pronounced 

 inner limitation." 7 ' Ranvier thinks that the double contour 



and the - ITntersuchungen " in Virchow's Archiv. vol. 36, (1866), pp. 357, 383, 387-8, 389 and 

 404, with Archiv fiir Mikroskopieche Anatomie, vol. XIV (1877), p. 93, or "On the minute 

 structural relations of the red blood-corpuscles," (translated from the preceding in) Quar- 

 terly Journal of Microscopical Science, Oct., 1877, p. 392. 



(1) "Eeitrag zur Kenntniss des Froschbluts," etc., I. c, p. 91. 



(2) " Kecherches sur la constitution physique du globule sanguin." Compt. rendus t. 85, 

 (1878), No. 16, pp. 712-715. 



(3) •' Sur la structure du globule sanguin et la resistance de son envelloppe a l'action d« 

 1'eau." Ibid., No, 17 p. 761. 



(4) L. c. 



(5) Op- tit. Virchow's Archiv, vol, 36, (1866), pp. 392-395. 



(6) L. c, p. 408. , . 



(7) L. c, p. 386. 



