240 B. F, KINGSBURY AND PAULINE E. HIRSH 



A second possible interpretation of synizesis that occurred to 

 the writers when considering the resemblance of the degeneration 

 figures to extreme S3^nizesis, has been elaborated by Hertwig ('03) ; 

 that is, that synizesis and synapsis represent an abortive mitosis. 

 According to this view, on the one hand, synizesis represents an 

 'attempt on the part of the spermatogonia to divide again — 

 which fails; while, on the other hard the reputed conjugation of 

 chromosomes occurring at about this time is but the imperfect 

 fission and subsequent fusion of daughter chromosomes of such 

 abortive division. There promises to be some time before there 

 is any complete agreement as to the facts, let alone interpretation. 



As far as synizesis is concerned, the extent of the contraction 

 of the nuclear contents seems to vary, from a condensation in 

 which no detail of structure is discernible, to a tendency only, on 

 the part of the nuclear structures to withdraw from the nuclear 

 membrane. Since Meves ('07) , in his recent rather severe critique 

 of the synizesis and synapsis problem, is forced to admit such a 

 tendency at this stage of the growth of the spermatocyte, syni- 

 zesis must represent a real alteration of conditions, and is not an 

 artifact due to imperfect penetration or fixation. In Desm.og- 

 nathus, we still locate synizesis in the beginning of the growth 

 period of the spermatocyte. The contraction of the chromatin 

 in many specimens is not marked so that in many of the prepara- 

 tions it can be interpreted as little more than a 'tendency' to con- 

 traction. Furthermore, as was stated by Kingsbury ('02), 

 synizesis is only well marked in the early summer, among the 

 last spermatocytes to enter upon the growth period that season. 

 In this connection figure 4 and particularly figure 7 may be 

 examined, as well as the more enlarged figures 8 and 9 which are, 

 however, not particularly characteristic and are not introduced 



The suggestion was too briefly stated at that time to be easily interpreted. The 

 idea intended to be conveyed however was that in the 'play of forces,' whatever 

 their character, which determine the succession of spermatogonial divisions, the 

 termination of the period of multiplication must be thought of as due to a check- 

 ing of, or a loss of a power of nuclear synthesis— a 'running out,' as if from an ex- 

 haustion of 'material' which necessitates a long growth period— or leads to degen- 

 eration. The suggestion was hardly intended to have the force of a 'claim' as 

 Miss King ('08) states it. B. F. Kingsbury. 



