698 GEOFFREY LAPAGE 



stained material, confirms this and says that the nucleus of tli(3 

 ' bud ' is formed from ' chromidia contained in it when it is 

 first formed and derived from the chromidia scattered through 

 the cytoplasm of the parent '. 



He also says, however, that ' the nucleus of the amoeba takes 

 no direct part in the formation of the bud. There is absolutely 

 no evidence, either from observation on the live amoebae or 

 from the stained films, for any form of nuclear division con- 

 nected with the bud formation.' 



This latter statement might equally well have been made 

 about the spheres described in this paper. Wlien it is remem- 

 bered that I also, under the influence of the view that the 

 spheres were endogenous buds, found in my amoebae structures 

 which could easily be interpreted as chromidia, the parallel is 

 complete. 



Upon re-examination of my preparations, how^ever, I have 

 been unable to convince myself that the fine grains in my 

 amoebae were chromidia at all, and certainly I have never seen 

 anything resembling a collecting together of these grains 

 inside the spheres to form their nuclei. All the spheres had 

 a fully-formed vesicular nucleus, Wliile I nuist admit, there- 

 fore, that Martin may have been dealing with something quite 

 different from my spheres, I still am of the opinion, without 

 desiring to impugn his high reputation as an accurate observer, 

 that his ' buds ' were in reality of the same nature as my 

 spheres, that is to say, that they were amoebae of the same 

 or another species which had been ingested.-^ Two types of 

 amoebae were present in the cultures of Liston and Martin, 

 and it is possible that one kind was ingesting the other. 

 The method of cultivation of these organisms upon agar 



^ Dr. H. M. Woodcock, of the Lister Institute, tirst suggested to me, 

 ill 1920, that the ' buds ' described by Liston and Martin were probably 

 not true buds at all and thus gave me the clue to the real nature of the 

 spheres in my own cultures. Recently Dobell and O'Connor (8 a) have 

 expressed the same opinion. Compare, also, the still more recent remarks 

 of Woodcock (32) with regard to the need for care in the interpretation 

 of cultural forms of Protozoa. 



