274 Cardiff: Synapsis and reduction 



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be an artifact. Moore firmly believed, however, that this uni- 

 lateral massing of the chromatin was natural and said that " what- 

 ever the synapsis may eventually turn out to be it is evidently a 

 cellular metamorphosis of profoundly fundamental character. 

 He, as well as many later investigators, found that in many cases 

 the chromosomes emerged from synapsis in the reduced number 

 and frequently longitudinally split. 



From the fact that synapsis was by many considered due to 

 faulty fixation little attention was paid to it, and as a result some 

 of the most important periods in the reduction stages have been 

 overlooked. McClung ('02) holds that a unilateral massing of the 

 chromatin — synapsis — is an artifact and says that he has not 

 found it " when the material was well fixed and prepared. It has, 

 moreover, been found possible to produce the appearance at will. 

 He does not tell, however, how it may be produced at will. 

 Schaffner ('06) seems to take somewhat the same stand, that synap- 

 sis is due to killing agents, though he finds it " usually present 

 in his own material just as the spireme is fully formed. While 

 synapsis is still regarded as an artifact by some (Schreiner & 

 Schreiner/04) it is now very generally regarded as a constant and 

 essential stage in reduction, so much so that one of the recent 

 text-books, Coulter and Chamberlain ('03), considers it a constant 

 morphological character of the mother-cell. That it is a real and 

 not an artificial character I think there can be little doubt. In 

 not one of the dozen or more forms examined in the present work 

 was a unilateral contraction of the chromatin wanting at the proper 

 stage. It was found to occur as often in megaspore as in micro- 

 spore mother-cell. Though a number of different killing agents 



M 



were used there was no variation in the effect produced. In such 

 forms examined as Salomonia, Botrychinm, Dramia, Unifohnin, 

 Pedicularis, and others where the sporangia are developed acropet- 

 ally by a whole raceme or spike, all cells are under like condi- 

 tions and a comparative study is not difficult. In the above-men- 

 tioned forms synapsis was always found at a certain stage in the 

 development and persisted for some little time. Davis ('99) made 

 a careful study of the developing sporogenous tissue of Anthoceros 

 a form peculiarly well suited for such a work — to determine 

 whether the unilateral contraction of chromatin is due to killing 



