484 C. CLIFFORD DOBELL. 



by different wui-kers Avheu workiiig, apparently, upon the 

 same species, may to some extent find an explanation in this 

 circumstance. 



I would call attention to the fact that MencP — whose 

 studies have been carried on with quite different Bacteria 

 from those which I have investigated — lias arrived at a 

 similar conclusion. Many times Mencl has emphasised this 

 point — a point which is, I believe, of fundamental importance 

 for reaching a correct interpretation of the Bacteria. I am 

 rejoiced that in this we ai-e both agreed. 



Pleoniorphism. — Though I have no conclusive evidence 

 to add to what has already been contributed to the hypothesis 

 of the pleoniorphism of Bacteria, nevertheless, I must point 

 out that many of the facts recorded in the earlier part of this 

 paper are consistent with such a view. 



Whilst investigating the Micrococcus, Cocco-bacillus 

 and Bacillus foi'uis which I found in the gut of the lizard, I 

 was often impressed by the apjiarent genetic relations existing 

 between tliem. The same was the case with many of the 

 different bacillar forms which I found in the blood of Sacco- 

 branchus. I have already pointed this out in previous 

 pages, and although a direct proof of such genetic continuity 

 is wanting, my observations are completely in accord Avith 

 such an interpretation. This appears to me, in fact, the most 

 probable hypothesis at present : otherwise it would be neces- 

 sary to assume the existence of an almost inconceivably large 

 number of species to account for the number of intermediate 

 forms which occur. 



For my own part, I believe — although this is a view which 

 is not held by the majority of "bacteriologists" — that the 

 greater number of Bacteria are pleomorphic. That pleo- 

 niorphism does exist in many Bacteria, I think there can be 

 no longer any doubt. Since the early work of Ray Lankester, 

 Cieukovvski, Zopf, Metchnikoff and others, an immense mass 

 of evidence has been brought foi-ward in favour of such a 

 view. It is outside the limits of the present paper to enter 

 ' See especially liis studies ou water Bacteria (Mencl, 1905). 



