642 SUMMARY OF CURRENT RESEARCHES RELATING TO 



endowed with spontaneous movement. M. Olivier, therefore, thought 

 it interesting to examine whether the same was the case with Monas 

 Okenii, or whether, on the contrary, their long filaments are formed 

 in a different manner. 



In a large graduated vessel 30 c.cm. of water was collected so rich 

 in Monas Okenii as to be coloured red by them. One c.cm. of 1 per 

 cent, osmic acid was added, and five minutes afterwards the vessel filled 

 with distilled water, in order to weaken the destructive action of the 

 acid. The next day all had fallen to the bottom, and by simple 

 decantation an immense number could be collected in a very small 

 bulk. Observed under the Microscope they presented different degrees 

 of division. Those in which the segmentation was the deepest appeared 

 to be entirely separated into two distinct masses. This is the case 

 during life also. We then see two masses of the same shape opposed 

 end to end, but leaving between them a transverse furrow which is 

 quite colourless. When the Monad moves, these two masses move 

 simultaneously, showing that they are united by a real though 

 invisible tie. But if, when killed by osmic acid, they are subse- 

 quently treated with Paris violet, that which before had the appear- 

 ance of a hyaline furrow — a complete interval between the two 

 segments of the body — immediately becomes coloured in the same 

 way as the best characterized filaments. This portion appears to be 

 in continuity with the protoplasm, no reagent distinguishing one part 

 from the other. As the two segments of the body become further 

 separated, this connection grows thinner and finally breaks. Although 

 he did not succeed in following all the phases of this phenomenon in 

 their successive order, the author " attributes to the connection which 

 unites the two segments of the Monad the same nature as to the long 

 and slender filament previously described. Like this filament the 

 connection is invisible without special preparation, but is easily 

 recognized when coloured with Paris violet." 



Cohn has remarked that the Monas in act of transverse division 

 have a cilium at both extremities. But, in fact, one extremity is 

 much more often destitute of any. The formation of a cilium at the 

 free extremity of & Monad was never observed. The filaments, always 

 cylindrical, are evidently flexible, for they present every imaginable 

 appearance and position when coloured with Paris violet after being 

 killed by osmic acid. Some experiments on dead organisms lead to 

 the conclusion that the filaments are contractile, for on putting 

 them into distilled water they in a few days disappeared ; and this 

 disappearance can only be explained by destruction or contraction. 

 When the animals are fixed by osmic acid, left for some days in 

 distilled water, and coloured by means of Paris violet, the filaments 

 become visible ; and it therefore seems that the osmic acid, by in- 

 stantly killing them, prevents a contraction which would otherwise 

 take place. 



All these facts show that Monas Ohenii does not resemble any 

 species of Bacterium. Their organization, on the contrary, refers 

 them to the nude-flagellate Infusoria, as for example, Spumella. Like 

 a great number of Infusoria (especially the Euglenw), they seek the 



