Germ Cells of Leptinotarsa Signaticollis. 153 



the nutritive material extending from the mouth of the nutri- 

 tive string to the nucleus and even slightly beyond, as shown in 

 Fig. 11. This is from a preparation killed with Flemming's 

 solution, and owing to this method of fixation, the food stream is 

 not differentiated as clearly as in material prepared in other ways. 

 The fact that the nucleus is at this time, composed largely of an 

 acid-staining ground substance, while the granules of the food 

 stream are basic-staining, points to the existence of a chemical 

 attraction between them. 



Preparations made with picro-acetic acid, and stained with 

 safranin and lichtgriin were found to be very valuable in studying 

 the nutritive process, and the following account is based on such 

 material. 



Fig. X represents a longitudinal section of an egg at the height 

 of the functional activity of the nutritive string. The dark area 

 shows the region where the red basic-staining granules are thick- 

 est, and the lighter area where the acid-staining material predomi- 

 nates. The configuration is quite different from that described 

 as typical of the early growth period. 



The nucleus (n.) shows a green acid-staining ground work in 

 which are embedded a number of more or less vacuolated basic- 

 staining nucleoli of various sizes. The egg string (n. s.) is seen 

 leaving the egg at the lower end of the follicle, only a short por- 

 tion of it showing because of a bend in the tube. This figure shows 

 clearly that the nutritive material is a basic-staining substance; 

 that is, a compound containing an organic acid resembling the 

 nucleic acid of the nucleus in its ability to unite with the dye. 

 Nucleo-albumens have been known for a long time to occur in the 

 yolk of eggs, so that it is very likely that the acid constituent 

 of the nutritive stream is nucleic acid in one form or another. 

 As might be expected this material shows important differences 

 in staining reaction from the chromosomes, since the latter, if 

 they are to be considered identical with the contents of the heads 

 of spermatozoa, yield only phosphoric acid and xanthin bodies 

 as splitting products, while the nucleo-albumens (pseudonucleins) 

 yield protein and phosphoric acid, but no xanthin bodies. Thus 

 while the chromosomes always stain deeply with safranin regard- 



