OxV THE DIVISION OF NUCLEI IN THE MTCETOZOA. 521) 



On the Division of Nuclei ir/the Mycetozoa. 



By Abthub Lisi^it, F.L.S. 



[Read 2nd February, 1893.] 

 (Platks XXXV. & XXXTI.) 



At a meeting of the Society on Dec, 1st, 1892, I exhibited a 

 series of preparations showing the changes which took place in 

 the nuclei of Mycetozoa previous to the formation of spores in 

 the sporangium. I gave an account of my investigations on the 



subject, which I now offer in greater detail, together with ob- 

 servations on nuclear division in the swarm-cells, a point which I 

 referred to at the meeting as requiring further elucidation. 



In De Bary's work, dated 1884 * he states : — " Nuclei were not 

 at first observed in the plasmodia; Cienkowski even stated 

 expressly that the nuclei present in the swarm-cells disappeared 

 when they coalesce ; Schmitz and Strasburger have recently 

 established the presence of nuclei in the plasmodium, and it may 

 be presumed that they are the persistent nuclei of the swarm- 

 cells and the products of their division." 



Strasburger published in ' Botanische Zeitung,' May 1884, 

 his account of the development of the sporangia of Trichia fall ax. 

 He gathered a large number of sporangia in different stages of 

 growth, and cut sections after hardening them by different pro- 

 cesses and embedding in elder-pith. In some of these sections he 

 discovered division of nuclei taking place with the now well- 

 known figures of karyokinesis ; and he states, " Very possibly 

 this mode of nuclear division takes place only at the stage 

 immediately preceding spore-formation ; previously the number 

 of nuclei did not appear to increase, whereas final division would 

 be necessary to provide the smaller nuclei we find in the 

 spores." 



I exhibited at the meeting a photograph taken from a thin 

 network of creeping plasmodium of Badhamia utricularis, killed 

 with alcohol while the streaming was in full activity over a 

 thin cover-glass, and stained with magenta, x 450. It showed 

 the nuclei in large numbers. I also showed several of such 

 films killed with Flemming's fluid stained with picrocarmine 

 and mounted in balsam ; these exhibited the vast abundance of 

 the nuclei more clearly. 



For several years past I have endeavoured to discover by what 



* ■ Comparative Morphology and Biology of the Fungi, Mycetozoa, and 

 Bacteria.' Oxford ed. 1887. 



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