A Comparative Study of the Structure and Origin of the Yolk Nucleus. 705 
archoplasm and centrosome, which show no trace of chromatm as is 
claimed by some other observers, and which persist in the oocyte giving 
rise to the yolk nucleus (vitelline body) of larger eggs. 
The final conclusion of Balbiani (4) 1893 is expressed as follows: 
“Le noyau vitellin (Dotterkern) des Araneids est Thomologue du Neben- 
kern (centrosome de Platner) des cellules seminales et du centrosome 
des cellules somatiques.” 
Miss King (40) by a peculiar confusion of terms says of the vitelline 
body in Bufo : “Judging from its staining reaction, this body is not chro- 
matin; neither is it the centrosome, since the same section of the cell 
may show both of these structures.” 
Gurwitsch (31) speaking of mammalian ova says: “Wir können 
somit mit gutem Rechte den Dotterkern der unreifen Säugetiereier dem 
Idiozome der Samenzellen vollständig homologisieren — also : Der Dotter- 
kern ist in jeder Eizelle voll ausgebildet vorhanden.“ 
Of the same eggs Winiwarter(96) says: “Le rapprochement avec une 
sphere attrac-tive devient encore plus manifeste si l’on songe que lesspicules 
que j'y ai observes, ont ete signales par Meves dans une formation reconnue 
avec certitude comme sphere attractive et d’un stade correspondant.” 
In 1898 van der Stricht (87) said: “Pour ce qui concerne l’oocyte 
humain, il est incontestable que au point de vue morphologique le noyau 
vitellin presente une resemblanee frappante avec la sphere attractive . . . 
II resulte de ce cpii precede que le noyau vitellin de l’oocyte humain est 
une formation, qui au point de vue physiologique doit etre considere 
comme un centre, qui tient sous sa dependance la genese du deutoplasma.” 
He has also said: “Elle correspond evidemment au centrosome de Boveri 
ou bien au corpuscule central, plus la zone medullaire de la sphere attractive 
de van Beneden.” 
Skrobansky (85) figures the vitelline body of Balbiani in the human 
ovum and also in the cat, resembling very closely some of the forms figured 
by Munson in his work on Limulus. Skrobansky seems to regard yolk 
bodies which make their appearance later as the disintegration product 
of the yolk nucleus, since they appear when the former disappears. i 
In 1885 — 1889 Rabl (74) said: “Wenn wirklich die Attraktions- 
sphäre, beziehungsweise das Polkörperchen, ein Bestandteil jeder Zelle 
ist, so müssen wohl auch das unbefruchtete Ei und das Spermatozoon 
dieses Organ besitzen. Aber gerade die neueren Untersuchungen haben 
darüber nichts von Belang zutage gefördert.” 
The numerous recent investigations make these words of Rabl no 
longer true. But these same recent researches tend to show that Rabl’s 
