THE EGG OF THE DOMESTIC CAT 143 



i.e., the follicular fluid through several hundred sections of one 

 follicle \^^ill be stained the identical shade of blue, while the stain 

 of a neighboring follicle will be of a different shade, but will 

 possess the same uniformity of coloration. This fact seems to 

 be related as closelj" to the physical condition of the contents of 

 the follicle as to any variation in their chemical composition 

 corresponding to their stage in degeneration. But, whatever 

 the cause, the result is the same. Different follicles are aligned 

 in the same group, and may be compared vvith one another. The 

 common characters of the group may thus be obtained, and the 

 different groups arranged in the order in which their morpholog- 

 ical characters show that they have departed from the normal. 



The use of the stain is twofold. By the difference of its action 

 it emphasizes the fact that different stages of degeneration exist 

 contemporaneously, i.e., that it recurs more or less periodically. 

 Farther, by its ability to group the stages, it performs the 

 equivalent of a reduction in the number which it is necessary 

 to consider. 



Living cat eggs were obtained both from the ovary and the 

 Fallopian tubes. In the former case the ovary was placed under 

 the binocular microscope in 0.7 per cent salt solution in a Syra- 

 cuse dish. Pricked with a needle and subjected to a slight pres- 

 sure, large follicles readily give up the eggs they contain, each 

 surrounded by its discus proligerus. So surrounded, the egg, 

 having once been located, is an object easily recognized by the 

 naked eye, and by means of a fine pipette it may be readily trans- 

 ferred as desired. 



After ovulation had occurred, eggs were obtained by taking 

 a portion of the Fallopian tube, placing it with a few drops of 

 salt solution on a slide on the stage of a dissecting microscope 

 and with a dissecting needle or other instrument stroking it 

 gently in the direction in which the eggs w^ould normally move. 

 Although R. Van der Stricht ('08) states that this method was 

 suggested to him by M. Tourneux of Toulouse, it seems to have 

 originated with William Cruikshank, 1797, and to have been 

 commonly employed by Martin Barry in his researches in embry- 

 ology. 



