SHAPE OF MAMMALIAN RED BLOOD CORPUSCLE 455 



of blood, thus obtained without direct contact with the air, was 

 touched to a cover and suspended, as a hanging drop, in the 

 Hfe cell,^ Vasehne served to seal the cell, the air in which could 

 be kept saturated with moisture by previously introducing a 

 drop of water and sealing. The entire procedure demands no 

 more time than in making ordinary preparations; if a large drop 

 of serum be used, the evaporation prior to sealing is inconsider- 

 able whereas further evaporation within the life cell can not 

 occur. 



A microscopic examination of blood prepared according to 

 this technique reveals numerous isolated corpus,cles. A favor- 

 able place for scrutiny is near the center of the drop. Here 

 sinking corpuscles revolve slowly, showing alternately their two 

 faces. Usually a few cups can he found, whereas quantities of 

 biconcave discs are seen in every field.^ Streaming movements 

 initiated by rolling the suspended drop towards the edge of 

 the cover also allow many corpuscles to be viewed from both 

 surfaces. 



Another technical procedure, used by Jordan ('15) in his 

 experiments with physiological solutions, consists in filling 

 shallow concave sUdes with serum into which the drop of diluted 

 blood, prepared as before, is introduced. Evaporation is pre- 

 vented by immediate sealing with a cover glass and vaseline. 

 Body temperature is maintained by the aid of the electrical 

 warm stage. The conclusions drawn from the study of many 

 such preparations substantiate those already reached with the 

 hanging drop. 



The necessity or desirability of observing blood which has not 

 been allowed to cool has been emphasized by those who uphold 

 the normality of the cup shape. Weidenreich ('02) contended 

 that the use of cold slides and covers is largely responsible for 

 the widespread 'deception' as to the true shape of the red cor- 

 puscles; in his contributions of 1903, 1905 and 1910, however, 

 he apparently abandons this contention for he urges only the 

 necessity of rapid manipulation. Lewis ('04) states that as the 



* Room temperature 27°C. 



' The disc shape is retained in properly sealed preparations 48 hours old. 



