110 THE CONNECTIVE TISSUES, BY A. ROLLETT. 



embryoes kept in Miiller's solution, can easily at this stage be 

 split with needles into laminae. 



In pursuing the further development of cartilage, the ques- 

 tion arises of the capacity of cartilage cells to undergo division. 

 Cells in the act of division, or apparently originating from the 

 division of cells, are frequently met with, not only in embryonic 

 cartilages, but also in those of adults. Thus, in the first place, 

 cells may be observed containing two nuclei. It has also been 

 stated that the nucleoli are sometimes double, nor is it difficult 

 to demonstrate this in the cartilages of tadpoles. The division 

 of the nucleus has even been directly observed (as recently by 

 Kolliker).* The occurrence of two nuclei appears, however, to 

 be the only condition which is of frequent occurrence and easily 

 observed. (- It is not easy to decide whether in these cases 

 two new nuclei have originated in the place of one nucleus that 

 has undergone absorption, or whether the division of the 

 nucleus on account of its rapidity has escaped observation. 

 The division of the cell itself may, indeed, be readily followed, 

 since it depends on the formation of a groove encircling the 

 cell. It cannot, however, be stated that the division leads in 

 the first place to the formation of two nucleated protoplasmic 

 masses, lying in a common capsule. It would rather appear 

 that the division of the protoplasm is very intimately asso- 

 ciated with the formation of a capsular investing sheath for 

 the daughter cell. However closely the cells under observa- 

 tion lie in apposition to one another, it is still observable 

 when they are detached from the walls of the cavity by some 

 of the above-mentioned means that the cavity is itself divided 

 by a thin septum into two chambers. The differentiation of 

 parts in the entire plane of division consequently takes place 

 with great rapidity. The daughter cells are capable of forming 

 complete capsules, which gradually increase in thickness, and 

 are clearly to be distinguished from one another, not only 

 where they are in contact, but also where they touch the 

 capsule of the mother cell. 



The daughter cells originating in division can in like manner 



Gewebelehre, 1867, p. 24. 



Frey, Histologie and Histochemie. Heidenhain, loc. cit. 



