IOO MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



It was observed that this material lent itself to the study of the 

 living cell by means of the tissue culture method as described for 

 the chick embryo cell by Lewis, M. R., and Lewis, W. H. ('15) 

 and that not only could the most minute structures of the cell 

 be observed from day to day, but also these structures could be 

 experimented upon as readily as those of the chick embryo. It 

 was decided to study the mitochondria and other cytoplasmic 

 structures of the germ cells of Chorthippus curtipennis by means 

 of the tissue culture method. 



LITERATURE. 



Living Material. The earliest observations upon the living 

 germ cells of the Arthropods were those of von La Valette St. 

 George ('86) in which he made a careful study of the Nebenkern 

 of the spermatid and described the structure and behavior of 

 that body more completely than many of the later investigators. 



Chambers, R. ('15), in his microdissection studies on the germ 

 cell, for which he used the male germ cells of Disosteira Carolina 

 (grasshopper) and of Periplaneta americana (cockroach), gives 

 many interesting observations as to the behavior of the mito- 

 chondria during the spermatocyte divisions and he also describes 

 in detail the development of the axial filament of the spermatid 

 and spermatozoon, but apparently Chambers made no effort 

 to trace the cytoplasmic structures of the germ cells throughout 

 their development. The description of the mitochondria during 

 the spermatocyte divisions and the formation of the Nebenkern 

 of the spermatid agrees in general with that found for preparations 

 of Chorthippus curtipennis when stained with Janus green. The 

 development of the spermatozoon of Chorthippus, however, 

 takes place in quite a different manner from that described by 

 Chambers for the cockroach. 



Goldschmidt, R. ('15) states that it was possible to keep the 

 sperm cells of the moth Samia cecropia L. alive for three weeks in 

 cultures of haemolymph and that during this time many follicles 

 finished the process of spermatogenesis. Goldschmidt does not 

 describe the process of spermatogenesis, but merely states that 

 it corresponds with that described for fixed preparations. From 

 these studies upon Chorthippus it is quite evident that neither the 



