SHAPE OF MAMMALIAN RED' BLOOD CORPUSCLE 469 



a hibernating bat. For several reasons the bat might be ex- 

 pected to furnish valuable evidence on this problem and arrange- 

 ments are under way by the writer for the further study of these 

 animals. 



David ('08) first called attention to the resemblance which a 

 biconcave disc, viewed obliquely, bears to a cup, a deception 

 which is intensified by hi^h magnifications and which he illus- 

 trated by photographing glass models. Lohner ('10) developed 

 this idea and constructed an elaborate model (p. 448) which was 

 said to corroborate his view. That a biconcave corpuscle strik- 

 ingly simulates a cup when viewed obliquely is true, but that 

 this illusion alone has influenced a decision on the part of other 

 observers favoring the cup shape seems improbable. Cups and 

 discs viewed in profile are unmistakable and it is from profile 

 views that crucial evidence must be derived. 



But little need be added regarding the action of fixatives. 

 Serious doubt has been cast on the trustworthiness of standard 

 fixatives in preserving the original shape of red blood corpuscles 

 (p. 464). Both Radasch and Lewis regard discs as represent- 

 ing collapsed cups; ''It may be thought that the depression 

 which makes the cup is itself due to shrinkage, or due to vacuole 

 formation. The only proof to the contrary is to be had from 

 the circulating blood of a living mammal"- (Lewis '04, p. 516). 

 A critique of the methods and results of this 'only' source of 

 proof to the contrary has been sufficiently dealt with in the 

 foregoing pages. 



It is interesting that agents such as heat (Ranvier, '75), elec- 

 tricity (Lohner, '07), and ether or chloroform produce cups from 

 discs. It is perhaps significant that these so-called destructive 

 agents in each case alter discs to cups, not the reverse. 



A limited and probably inconstant number of cup-shaped 

 erythroplastids undoubtedly are present in normal blood. Pos- 

 sibly they represent corpuscles, whose structure is such that 

 unequal tensions with respect to themselves or to the osmotic 

 balance exist; perhaps they are old (or young?) corpuscles. In 

 anemias the presence of many cups has been reported (Quincke, 

 '77; Grawitz, '99) and in fevers it is said crenation may occur 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 22, NO. 3 



