410 Sidney I. Kornhauser 



l30iiquet stage. The threads, now less angular, seem to have their free 

 ends so strongly attracted to the positive pole that in a great many cases 

 they riin parallel to one another. Thus, from an optical section viewed 

 pole-Avise, one can get an estimate of their number. Such a section, 

 which is fairly accurate, considering the high power objective and ocular 

 used, is represented in Figure 13 (Plate V). The focus was taken 

 as nearly as possible through the middle of the nucleus and not changed 

 while making the camera drawing. The threads, so seen in end 

 view, have a deeply staining center, surrounded by a gray mantle. 

 Counts yielded between forty-five and fifty, which would indicate 

 that there are between twenty-two and tw^nty-five leptotene threads, 

 each of which, in the form of a loop, would l)e seen twice in an 

 optical section (Fig. 13). Such a representation is niost instructive, 

 however, when compared with similarly viewed cells of later stages 

 (Figs. 16, 18, Plate V). 



Eithor during the period in which the leptotene threads are still 

 in the form of a bouquet, or in the subsequent stage, the nucleoli come 

 together and fuse, and the cyto-plasmosomes unite to form a large 

 conspicuous "nuclear cap" {n.c, Fig. 12 /, 14, 15, 17). At the positive 

 pole the cytoplasm stains more deeply and appears more compact, or 

 less reticular in structure. Buchner ('10) has shown that, during the 

 bouquet stage in the spermatocytes of various organisms, a centriole, 

 often surrounded by mitochondria, can be observed at the positive pole. 

 To this centriole is attributed the force which causes the orientation 

 of the threads. In HersiUa, we have to deal, probably, with some force 

 acting from the positive pole, although the centrioles, which even in 

 the mitoses are inconspicuous, could not be seen. The substance which 



small minority of my numerous (175) i3reparations from eighty separate lots, fixed in 

 streng Flemmixg's fluid and all treated as nearly as ijossible in the same manner, that 

 such a contraction in these stages is not shown. I am strongly inclined to believe that 

 synizesis, at least in HersiUa, is an artifact; because, when it occurs, there always exists 

 between the contracted chromatin and the nuclear membrane a space devoid of proto- 

 plasmic substance. 



lüiüGER ('11, p. 176) believes that the contraction is not a product of the fixation, 

 in as much as he found it in "tadellos konservierten Stücken" (his Figs. 1, 2, Taf. VII). 

 He thinks, however, that Lerat's figures ('05, Plates I, IV) show an artificial 

 synapsis. A coraparison of the figm-es of Krüger and Lerat shows that both have 

 to deal with the same phenomena of shrinkage, somewhat more marked, perhaps, in 

 Lerat's preparations. Uoth investigators used Sublimate reagents, which, according 

 to the experience of the author, are the most unfavorable for a good fixation of these 

 delicate stages. 



