446 LESLIE B. AREY 



Jolly ('04), repeating Triolo's experiment with the blood of 

 the guinea-pig and man, constantly obtained discs; occasionally, 

 and especially at the periphery spheres or crenated forms were 

 seen. Weidenreich ('05 b) likewise pointed out that vaseline is 

 not an indifferent medium and that in ordinary preparations 

 rung with oil, the adjacent corpuscles also ultimately become 

 spheres. 



Jolly ('05; '06 a) discredits the cup shape on the grounds that 

 the separating lines in rouleaux are transverse and the terminal 

 corpuscles usually present a plane face, as do free corpuscles. 



By using oblique illumination and by observing rotating cor- 

 puscles David ('08) became convinced that the 'cup' is an opti- 

 cal illusion which high magnifications increase. He constructed 

 enlarged glass models of biconcave discs and filled them with 

 aurantia ; photographs of these taken at various angles apparently 

 depicted cups. True concavo-convex cups, as resting forms in 

 blood preparations prepared as quickly as possible, were not 

 seen. 



Ors6s ('09) was able to induce temporary mechanical distor- 

 tion in corpuscles but the return was to the biconcave disc which 

 he regards as the equilibrium form in isotonic plasma. 



Lohner ('10) decided that to avoid criticism such as had been 

 interposed drawn blood, should be examined vmder conditions 

 which eliminated the evaporation. Accordingly he constructed 

 a cabinet of sufficient size to contain a microscope and into 

 which he could insert his hands through arm-holes; this was 

 heated to a constant temperature of 38°C. and the air saturated 

 with moisture. When the apparatus had reached a state of 

 equilibrium as regards moisture and temperature, blood was 

 drawn from a finger and examined (p. 418): "Wurden nun 

 unter den angegebenen und jedenfalls ziemlich einwandfreien 

 Bedingungen Blutpraparate untersucht, so wurden stets und 

 ausschliesslich nur Erythrocyten in der Gestalt von bikonkaven 

 Scheiben wahrgenommen." To this experiment Weidenreich 

 ('10) replied with his famiUar objection — slowness of observa- 

 tion, due to the awkwardness of working in a cabinet ; he further 



