LEWIS. — POLYCH^TE ANNELIDS. 245 



rather than with von Lenhossek's " Centrosom," although Dehler does 

 not admit for each corpuscle the individuality and value which Heideuhain 

 attaches to each Centralkorper. Rather, he would limit such a value to 

 the entire " Centralkorpergruppe," thereby showing himself in agreement 

 with von Lenhossek. 



A word may here be said upon the methods employed by von Len- 

 hossek and Dehler. Both attach great importance to the use of corrosive 

 sublimate followed by iron ha3matoxylin for the demonstration of the 

 centrosome, and both state that treatment with osmic acid gives unsatis- 

 factory results, Dehler (p. 725) says: " Ich halte fiir das Studium des 

 feineren Baues der Nervenzelle die Fixierung mit Osmiumsaurelosuug 

 und ihren Combinationen fur weniger brauchbar, da sich die feineren 

 Gebilde diffus, verschwommen, eventuell schichtweise ungleich farben." 

 In regard to the use of osmic acid, my experience has been very different, 

 since I obtained my last and clearest preparations from material prepared 

 by vom Rath's ('93, p. 102) osmic mixture. After reading von Len- 

 hossek's paper, I took pains to confirm my results by his method, — the 

 use of corrosive sublimate followed by iron ha^matoxylin, — and the 

 results, although offering an excellent confirmation of the preparations 

 made with the vom Rath mixture, were in no respect better. 



A short time before the publication of Dehler's paper, Buehler ('95) 

 described " Centralkorper," in the sense of Heidenhain's term, found in 

 cells from the cortex of the forebrain of the lizard, and also in nerve 

 cells of the human brain. He says (p. 230, Separate, pp. 32, 33) : " Dem- 

 gemass bin ich vollauf berechtigt zu erklaren : Die Centralkorper, wie sie 

 Heidenhain in Leukocyten von Salamander und Kaninchen und in Riesen- 

 zellen des letzteren Tieres beschreibt, dieselben Centralkorper, die auch 

 Flemming vor ihm an ruhenden Leukocyten und Gewebszellen fand, die 

 eine Reihe anderer Forscher in verschiedenen Zellformen in Ruhe, unter 

 anderm ich selbst an den Samenzellen des Krotenhodens, gefunden 

 haben, diese Centralkorper Jinden sich auch in den Ganglienzellen der 

 Vorderhirnrinde der erwachsenen geschlechtsreifen Eidechse." 



Buehler also found radiations arising from the Centralkorper, or from 

 the group of Centralkorper. This is the only instance, save in that of 

 my previous paper (Lewis, '96), in which this significant feature has 

 been described or figured. Buehler says (p. 227, Separate, p. 19): 

 " Nicht selten finden wir Linien im Protoplasma, die annahernd radiar 

 verlaufend von den Kiigelchen aus nach der Peripherie der Zelle 

 hinstreben." 



Schaflfer ('96) announces a similar discovery for another vertebrate 



