THE VITAL PHENOMENA OF THE CELL 209 



It is in consequence of this delay in completing the process of 

 cell division after the nucleus has divided that cells containing 

 several nuclei are found. Sometimes, during inflammatory pro- 

 cesses, such cells become so large that they are called giant cells 

 (Fig. 101) ; the small nuclei vary considerably both as to form 

 and arrangement. Sometimes they are 

 globular vesicles, sometimes oval, sausage- 

 shaped, or lobulated bodies ; they may occur 

 singly and evenly distributed throughout 

 the protoplasm, or they may be arranged 

 in chains and circles ; finally, isolated small 

 nuclei are occasionally found arranged one 

 after another in rows. As time goes on, 

 small cells may become detached from the 

 giant cells, as has been observed by Arnold. 

 This may occur in one of two ways. FIG. 101. A large muiti- 

 " Sometimes the giant cell protrudes knob- nucleated ceil, with nucie- 



... , 1-1-1 ated cells becoming con. 



like processes containing nuclei, which, 8tricted off per ip h eraiiy. 

 after having been withdrawn and again (After Arnold, PI. xiv., 

 protruded several times, sooner or later 



become separated ; sometimes they become detached without any 

 or only very slight movement on the part of the cell." 



Cell division, accompanied by the phenomenon of direct nuclear 

 division, has been observed in epithelial cells, as well as in lymph 

 corpuscles ; this occurs with especial frequency in Arthropods. 

 They have been described by Johnson (VI. 41) and Blochmann 

 (VI. 86) in the embryonic cells of the Scorpion ; by Platner 

 (VI. 52) in the cells of the Malpighian tubes, and by other in- 

 vestigators in other objects. 



A peculiar method of nuclear constriction has been described 

 by Goppert (VI. 22), Flemming (VI. 16), von Kostanecki (VI. 46), 

 and others. The most suitable object for observing it appears to 

 be the lymphoid tissue on the surface of the liver of Amphibians. 

 According to Groppert, the nucleus of a lymph cell develops a 

 funnel-shaped invagination, which grows deeper and deeper until 

 it reaches the opposite surface of the nuclear membrane, where 

 it opens to the exterior by a minute aperture (Fig. 102 A, B). 

 Thus a ring-shaped nucleus, perforated by a narrow canal, is formed. 

 This ring becomes first constricted, and then cut asunder at a 

 certain point, whilst at the same time it transforms itself into a 

 semicircle, which becomes divided by superficial constrictions 



