SHAPE OF MAMMALIAN RED BLOOD CORPUSCLE 445 



molecular force'^ of a medium opposes the expansion of a plastic 

 body, then by diminishing the molecular force an expansion 

 should result; from Quincke's results it seemed probable that the 

 difference in the effect of isotonic salt solution and serum lay in 

 the presence of albumen in the latter. Gelatin was tried, three 

 per cent in 0.85 per cent sodium chloride solution. In this 

 medium bells were obtained, although excessive rouleaux forma- 

 tion and agglutination into masses occurred, making the result, 

 as frankly admitted, unsatisfactory. 



Hence Weidenreich gradually attained the view that the 

 shape of a corpuscle depends on: (1) osmotic pressure, i.e., salt 

 content of medium; (2) 'Molecularkraft,' i.e., colloid content of 

 medium; (3) probably the elasticity of the membrane. 



Hamburger ('02) found that corpuscles in lymph lost their 

 disc form and became cups.*^ 



Lewis ('04; '13) was the first ardent advocate of Weiden- 

 reich's contention. He reported that human blood on a warm 

 slide shows cup-shaped corpuscles but when the slide cools and 

 the corpuscles come to rest the conventional discs appear. 

 Weidenreich's early view that a 0.65 per cent saline solution is a 

 suitable examining fluid is apparently accepted and with identi- 

 cal results. 



Stohr ('06, p. 115) makes the following non-committal state- 

 ment: ''Sie haben beim Menschen und bei den Saugetieren 

 die Gestalt einer bikonkaven Scheibe auch eingedellten Blase 

 ('Glockenform') oder eines flachen kreisrunden Napfchens." 



Heidenhain ('04), on the contrary, rejected the general cup 

 thesis as unproven. 



By pricking his finger through a drop of vaseline Triolo ('04 a, 

 '04 b) obtained an embedded droplet of blood, the coagulation of 

 which was said to be retarded. Examination showed spheres, 

 which, he states, (p. 309) were 8-10 n in diameter (cf . p. 457) ; 

 " . . . . mais, jaimais dans le sang examine par ce procede 

 de la lubrification, on ne voit le figure classique du globule rouge : 

 le disc biconcave." 



^ The vagueness of this conception of the action of a 'molecular force' has been 

 justly criticized by Jolly ('05). 

 '^ Cited by Weidenreich ('02). 



