MATTEATIOX OF THE EGC, AXD PROCESS OF FEKTTLISATIOK. 37 



of the maturation of the egg were enveloped, has been in general cleared up, 

 the same is not the case if we inquire after its physiological nwMring That 



and a rich accumulation 

 to the interaction of protoplasm 

 and active nuclear substance in the processes of division. Its dissolution is, 

 as it were, the preliminary requirement for the renewed activity of the nuclear 

 contents. But what function sball one ascribe to the polar cells? 



Concerning this several hypotheses have been proposed. 



BALFOUB, SEDGWICK MLSOT. TAX BEXEDES, and others, are of opinion 

 that the immature egg, like every other cell, is originally hermaphroditic, and 

 that by the development of polar cells it rids itself of the male constituents of 

 its nucleus, which afterwards are replaced by fertilisation. BALFOTJR thinks 

 that, if no polar cells were formed, parthenogenesis must normally occur. 



WEISJUAXX, supported by his discovery in the case of eggs developing 

 parthenogenetically (p. 34), ascribes a different function to the first and the 

 second polar cells. He distinguishes m the germinative vedcle two different 

 kinds of p 1 **-!* y which he designates ovogenetic and germinal p 1 *"** 

 He maintains that by the formation of the first polar cell the ovogenetic 

 plasma is limiMt*l from the ovum ; by that of the second polar ceO, half 

 of the germinal plasma. In the latter case the ejected germinal plasma must 

 be replaced by fertilisation. 



Thffg hypotheses appear to * upon rloffft 1 * examination to pr*******! manv 

 vulnerable points. To me appears more promising an interpretation of 

 BUTSCHIJ, who compares the egg, as had already often been done, to the 

 MiQ*|K--<y|i of H|MM f "J-fffiQ'fr Just as thft lattiT gives rise to many tvpfi iiurtOTtM, 

 so fa^> the egg must have once poBm-flrofl the capability of dividing **Mf into 

 many eggs. In the formation of the polar cells, which are eggs that have 



t"6OC'!6 T"UCLLI!lr Hilary. T^5 IT TrT^. t rTr H.Vf r>^rll TT-r >rT "r - -i "r.^.- -I 1_T?-5 



original conditions. Also BOTERI regards the polar cells as mortice eyyt. 

 I have likewise always conceived of the conditions in this manner. 



& The Process of 



The union of egg-cell and spermatic cell is designated as the process 

 fertilisation. This process is to be observed, sometimes with great 

 netimes with considerable ease, according to the choice of 

 for experimentation. The investigator ordinarily en- 

 great difficulties meases where the ripe eggs are 

 part, if not the whole, of their development is effected within 

 ducts of the maternal organism. In such cases the fertili- 

 also must evidently take place in the duets of the female sexual 

 into which the semen is introduced in the act of 



internal fcrtiJ^atio* takes place in nearly all Vertebrates 

 tbegre^er part of th^Fishesandmaiiy Amphibia. Usually the 

 and the spermatozoa meet, in the case of Man and Mammals, in 



