SHAPE OF MAMMALIAN RED BLOOD CORPUSCLE 461 



(Jordan). To avoid this pressure I employed an immersion 

 objective with Tyrode's sohition, as in the water-immersion 

 lenses of former days ; in this way the spread omentum was ob- 

 served directly without the aid of a cover glass. A Leitz no. 4 

 dry objective and a no. 12 compensating ocular, with the draw 

 tube of the microscope set at 190 mm. also gave a very satis- 

 factory magnification and was used extensively as a check on 

 the wet method. 



The omenta of eight cats and two dogs were studied continu- 

 ously for periods from one to four hours. The animals used were 

 purposely in a state of deep surgical shock resulting from previous 

 laminectomies', in each case the anesthetic had been stopped two to 

 four hours prior to the experiment. 



Capillaries of sijialler calibre than the diameter of an erythro- 

 plastid are obviously unsuited for observational purposes. Both 

 the vessels figured by Lewis ('13) are open to this objection; 

 of the eight cup-shaped corpuscles shown in edge view, six if 

 flattened to discs would exceed considerably the diameter of 

 their containing vessel. 



Regions of the omentum where temporary stases have caused 

 corpuscles to adhere in clumps or agglutinated masses I do not 

 consider favorable; when the flow is resumed many cups are 

 seen, the cup form apparently being in some way referable to 

 the former massed condition.^* The rapidity of normally cir- 

 culating blood makes it impossible to observe satisfactorily the 

 individual corpuscles which pass across the field as an ill-defined 

 blur;^^ in the rhythmical release from stasis which sometimes 

 occurs in a pulsating fashion the corpuscles are mutually com- 

 pressed to an unfavorable degree. 



Since ordinary circulation is much too rapid to enable accu- 

 rate observation, I believe that the most reliable data are obtain- 

 able under the following conditions. It is sometimes possible 

 to find a bifurcation of precapillary or larger vessels in which 



" It is to be noted that Weidenreich ('02) made his observations when the 

 current had slowed to the point of incipient stasis. 



''• Such illustrations of corpuscles within vessels, as figured by Lewis ('13) 

 could not have been drawn from normally circulating blood as the legend implies. 



