411 



which are some cup-shaped forms due to the peculiar structure of 

 the corpuscle. 



In a hanging drop on a warmed slide, prior to rouleaux form- 

 ation, the majority of the corpuscles are disc-shaped. I believe that 

 this condition where the cover slip is sealed with vaseline (which 

 protects from cooling and evaporation) is as close to normal as can 

 be obtained outside of the body. Some "cup-shaped" bodies are seen 

 but they are very far from preponderating even with the most liberal 

 interpretation of doubtful forms. As the slide cools rouleaux are formed, 

 all the corpuscles of which are biconcave discs except occasionally the 

 terminal one. The latter is frequently cup-shaped and always has its 

 bottom fitted onto the "delle" of the next succeeding corpuscle. 



Occasionally one sees an isolated cup-shaped form even at this 

 stage. But for the most part such shapes are met with only at the 

 ends of rouleaux or wedged in between two adjoining rouleaux. Now 

 these are exactly the locations in which one would expect a structure 

 such as we believe the red blood corpuscle to be, to be modified by 

 pressure and adhesion into a cup-shaped body. I do not deny the 

 presence of cup-shaped corpuscles either in the circulating blood or 

 in fresh preparations, but I hold , that the biconcave disc form prepon- 

 derates in numbers (very generally in the hanging drop) and that all 

 variations from this shape can be interpreted in the terms of pressure, 

 contact, or contraction. 



Accordingly, I believe that the biconcave disc is the normal shape 

 and all others simply variations or modifications of this typical shape. 

 It is certainly very much easier to conceive of a biconcave flexible 

 disc changing into a cup than the latter changing into such a regular 

 disc as is characteristic of rouleaux. And there appears not a single 

 valid reason — there is not even any support by way of analogy with 

 lower vertebrates; in fact, analogy with the elliptical discs of Came- 

 lidae is strongly against the cup-shaped form — to support the position 

 that the normal shape of the mammalian red blood corpuscle is really 

 diflerent from what it most frequently appears to be. 



I do not believe that any cogent proof respecting the shape of 

 anything so delicate as a red blood corpuscle can be obtained from 

 a study of fixed tissue no matter how carefully prepared. However, 

 since arguments in favor of the cup-shaped form have been drawn 

 from much preparations, 1 desire also to record my findings. In 

 fixed and stained blood smears, the corpuscles certainly appear disc 

 shaped. How can one imagine a deep cup-shaped form to spread 

 out into a flat disc with perfect contour? In sections representing 



