No. 2.] THE SPERMATOGENESIS OF LUMBRICUS. 285 



tions which have been imbedded either in paraffine or in 

 celloidin, the archoplasm does not stain so readily as in teased 

 specimens. Second, different killing agents affect the archo- 

 plasm in different ways. After Hermann's fluid it is large and 

 has a more or less reticulated appearance. After picric or 

 chromic acid or corrosive sublimate it is much contracted, and 

 in full karyokinesis appears as a minute and homogeneous dot 

 at the spindle pole. The differences in appearance following 

 the use of these various reagents is quite remarkable and can- 

 not be attributed to individual variation in the several cells. 



I have been unable to trace the early history of the archo- 

 plasm in spermatogonia, but in the fully developed spindle it 

 may be seen at the two poles (Fig. 8, a specimen killed with 

 picric acid). There is here no indication of radiating cyto- 

 plasmic fibres (astral rays). 



The archoplasm is a much more favorable object for study 

 in spermatocytes of the first order, since it may be observed in 

 teased specimens which can be more easily stained, whereas 

 in spermatogonia the cells are necessarily studied from sec- 

 tions. In teased preparations from the vesicles the sperma- 

 tocyte archoplasm can be best demonstrated by staining with 

 Kleinenberg's haematoxylin. An exposure of fifteen minutes 

 is sufficient to turn them a dark blue, the other structures of 

 the cell remaining quite unstained. The archoplasm masses 

 are then so distinct that their history can be easily followed, 

 although preparations which show these changes to the best 

 advantage do not indicate the corresponding changes of the 

 chromatin, and the various parts of the cell must, therefore, be 

 studied independently. 



The normal position of the archoplasm is at the distal ex- 

 tremity of the nucleus, although I have frequently seen it at 

 the opposite extremity as well as at all intermediate positions. 

 In some cases it is elongated and flattened and lies closely 

 applied to the exterior of the nuclear membrane. In other 

 cases it is divided into finger-like processes and loops, closely 

 resembling certain stages of the so-called Nebenkern as figured 

 and described by Platner ('85) in the spermatic cells of Liniax 

 ag. and Helix pomatia. Again it is in the form of a sphere ; 



