SO-CALLED PARTHENOGENESIS IN THE WHITE MOUSE. 24! 



Iii the white mouse, it is certain that the changes taking place 

 in the oocytes are in some way correlated with the atresia of the 

 follicles, for in follicles which have not begun to degenerate the 

 egg-cells are normal in appearance and the nuclei are normal 

 resting nuclei. But in follicles overtaken by atresia the cyto- 

 plasm of the oocytes is found to stain more deeply with acid 

 stains, fat granules are found in large numbers, and the nuclei 

 are in various stages of mitosis. The degeneration of the follicle 

 in some w r ay stimulates the oocyte so that it passes through more 

 or less abnormal maturation stages. 



The early prophase is probably passed through very rapidly 

 as no stages were seen of nuclei between the resting stage and the 

 equatorial plate stage. Lams and Doorme ('08) did not observe 

 the stages between the resting nucleus and the first polar spindle 

 in the normal maturation of the egg of the white mouse. Kirk- 



("6:3:1"), Hermann's, and Flemming's fluids. Heidenhain's iron hematoxylin, 

 Jenner's blood stain, and Flemming's triple stain were used. Sections were stained 

 over night in Jenner's stain, diluted with three parts of water; this stain was used 

 after fixation in Carney's fluid and gave excellent results for some purposes. The 

 cytoplasm of degenerating egg-cells was stained a much deeper pink or red than 

 that of normal egg-cells. The nuclei of follicle cells and phagocytic cells were 

 stained a deep blue. The stain will fade after a time, however. 



A modification of theshorter method of Flemming's triplestain was used. Sections 

 of material fixed for two to four hours in Flemming's or Hermann's fluid were 

 bleached in a dilute solution of hydrogen peroxid and after rinsing were placed in 

 a four per cent, solution of ferric alum for four to twelve hours. The sections 

 were then rinsed in distilled water, dipped in the safranin solution a second or 

 two, rinsed again in distilled water, and placed in the gentian violet solution for 

 two to ten or fifteen minutes. Then after rinsing in distilled water the sections 

 were stained in the orange G for ten to sixty seconds. After dehydrating rapidly 

 in absolute alcohol the sections were differentiated in clove oil under the control 

 of the microscope. The clove oil was removed by toluene or xylene and the sections 

 mounted in balsam. By this method the cytoplasm of the oocytes was stained 

 a yellow-brown, the chromosomes were stained a violet, and the spindle fibers a 

 dark violet almost purple. The method is rather capricious but when successful, 

 the spindle fibers stand out very distinctly against the yellow-brown cytoplasm 

 of the egg-cell. The method was used principally to bring out the spindle fibers, as 

 the chromosomes are not stained so distinctly or sharply as by the iron hematoxylin 

 method. 



The solutions used are as follows: 



f Safranin, saturated solution in absolute alcohol, i part. 



\Safranin, saturated solution in distilled water, i part. 



2. Gentian violet, i per cent, solution in distilled water. 



3. Orange G, 2 per cent, solution in distilled water. 



