450 LESLIE B. AREY 



Fuchs ('03) decided that Zenker fixation preserved the origi- 

 nal cup shape, whereas he had formerly thought the cup to be an 

 artefact. 



Osmic acid was found to produce cups and spheres by Jolly 

 ('05), who, however, questioned the significance of the result 

 ('06 a) because he believed swelling occurred. Later ('09), hav- 

 ing first observed circulating discs in the bat's wing, he fixed an 

 area in situ with 1 per cent osmic; after fixation the corpuscles 

 were found to be spheres. 



Lewis ('04) showed that pricking through a drop of osmic 

 acid produced many shrunken corpuscles and cups. Zenker's 

 fluid acts violently on drawn blood. From the study of the 

 tissues of various mammals he concludes (p. 516) : "In preserved 

 mammalian blood the typical red blood corpuscle is cup shaped. 

 The biconcave disc is but one of several forms of shrunken 

 cups" In 1913 he again says (p. 192): ''.... in well 

 preserved tissues of all sorts, and with all fixatives such as are 

 relied upon to reveal the structure of other tissues the mam- 

 malian erythrocytes are typically cup-shaped. . . . where, 

 the tissues in general are excellently preserved the corpuscles ap- 

 pear as cups. The biconcave discs are flattened cups." 



Weidenreich ('02) considers the evidence gained from the use of 

 fixatives (e.g., 1 per cent osmic acid) alone sufficient to establish 

 the cup shape. In 1905 b he stated that osmic acid preserves 

 corpuscles which have become discs as discs. Later ('06 a) he 

 recommended a rapid method for preserving smears by osmic 

 acid vapor; the form was said to be fixed in three to five sec- 

 onds, this being less time than is required for the corpusles to 

 change shape osmotically. 



Human material, several hours old, was preserved by Radasch 

 ('06). Several organs of the body were examined, including 

 the placenta with its maternal and fetal blood. A large majority 

 of cups were observed. 



Jordan ('09) records his experience with fixatives although he 

 discounts the value of evidence obtained by such methods. 

 With various reagents cups, irregular forms, and a few irregular 

 discs were found whereas in one Zenker-fixed preparation discs 



