648 



SCIENCE 



[N. S. Vol. XL. No. 1035 



latory movement, wliile still others are abso- 

 lutely motionless. These processes, which can 

 be seen to be thrown out from the cell and 

 possess unquestioned continuity with the cell, 

 apparently originate from small blunt projec- 

 tions which appear on the surface of the cell. 

 These processes appear alike on crenated and 

 uncrenated cells, are comparatively easily seen, 

 and vary in length from two to three microns 

 to as long as 30 microns. Under certain con- 

 ditions, the details of which have not been 

 worked out, they are capable of extremely rapid 

 retraction. Frequently oval erythrocytes with 

 the two ends drawn out into a long fine 

 whipping process which may have a length 

 of five to six times the diameter of the cell are 

 found. Cells with these beating processes are 

 rapidly whipped across the field. These long 

 fine processes, when they first appear on the 

 red cells, are of a clear, non-granular nature. 

 After whipping for twenty to thirty minutes 

 they have been seen to take on a granular, 

 beaded appearance. The beaded processes con- 

 tinue to beat. If watched, certain of these 

 processes can be seen to break off from the 

 cell, and even after being detached, continue 

 to whip across the field. If these detached 

 processes are further observed they can be 

 seen to eventually break down, the granules 

 floating free in the preparation and exhibiting 

 marked Brownian movements. These gran- 

 ules apparently hold up, and at the end of 

 five or six hours are found in large numbers. 



By means of the microdissection technique 

 devised by Kite the fine beating processes on 

 the red blood cells have been dissected off. 

 When a process is dissected off the cell, the 

 broken-off process may remain sticking to the 

 point of the needle. The free end continues to 

 whip for as long as forty minutes after being 

 detached from the cell. If a process be dis- 

 sected off near the cell the small portion re- 

 maining attached to the cell continues to 

 whip. 



If a motionless process on an erythrocyte is 

 touched at any point along its extent by a 

 very fine needle the process immediately begins 

 to whip. For instance, an erythrocyte of per- 

 fectly regular outline with a long (20-30 



micron) process at each pole of the cell was 

 watched for forty-five minutes. During this 

 time the cell did not change in outline, and the 

 cell and its processes remained absolutely mo- 

 tionless. At the end of this time one of the 

 processes was touched near its base. The proc- 

 ess immediately commenced to whip, and the 

 motionless process at the other pole of the cell 

 took on a very slow undulatory movement. 

 When this latter undulating process was 

 touched by the needle, it, too, immediately 

 commenced to whip. The two actively whip- 

 ping processes soon carried the cell out of the 

 field, and the cell was followed in its progress 

 through a number of fields. At the end of 

 thirty minutes the processes were still whip- 

 ping the cell through the preparation. The 

 long processes are exceedingly flexible and 

 seem to beat in an arhythmic manner. They 

 frequently are seen to whip around the cell to 

 which they are attached, and become glued to 

 the surface of the cell. After several minutes 

 they can be seen to beat free from the cell and 

 continue their active whipping motion. The 

 apparent viscidity of the processes is evi- 

 denced by the fact that two or more beating 

 processes of the same or neighboring cell fre- 

 quently become entangled and stick together. 

 They may become freed naturally, or they can 

 be pulled apart by means of the dissecting 

 needle. At times the middle portion of a long 

 process becomes stuck to the cell while the 

 free terminal portion continues to whip. 



If a dissecting needle be brought up along 

 side the middle portion of one of these long 

 beating processes, and this portion then be 

 carefully pushed so as to form an are, the distal 

 portion of the process continues to beat in a 

 line with the motionless proximal portion. If 

 too much tension is placed on the process it is 

 torn loose. The various types of motile and 

 non-motile processes on the red-blood cells can 

 be found in moist chamber preparations of 

 blood mounted in 0.85 per cent, sodium 

 chloride for many hours after the preparation 

 is made (at least twenty-four hours). 



Wade W. Oliver 

 Marine Biological Laboratort, 

 Woods Hole 



