186 . THE ZOOLOGIST. 



A NOTE ON PAEASITIC KERONA. 

 By the Eev. H. Victor-Jones, F.Z.S. 



The psychical life of the Protozoa has always been a puzzle 

 to the biologist. A puzzle because, bo often, into the play of 

 life of these microscopic animals there enters an element which 

 controls the action and mode of persisting of each individual 

 organism, and this element defies classification. 



The question is still in abeyance as to whether the series of 

 effects constituting the life-history of these lowly organisms is 

 merely and solely a chemical stimulus and a mechanical response, 

 or whether we ought to bring in the incipient germs of " know- 

 ing " — of intelligence. Kerworn, after tremendous labour, came 

 to the conclusion that the Protozoa do not show the slightest 

 trace of intelligence. Jennings, too, thinks that their life is 

 a series of " trial and error." But these assumptions are still 

 far from satisfying, and with many noted biologists we concur 

 in the statement " that after all we must not dismiss the 

 possibility that in the possession of these lowliest of the low 

 there may be the slightest vestige of the proto-psychic power 

 of analyzing the causes thrust upon them, and which bring out 

 the decidedly problematic effects constituting the life of the 

 unicellular organism." 



The greater number of Protozoa are parasitic, and we can 

 easily understand why many types have, each, their own peculiar 

 and particular type of host, but there are other cases which 

 seem to demand that we stipulate to the parasite a certain 

 amount of control over circumstances. The psychical life of 

 the lower types is as yet so little known that it is, indeed, 

 unwise to dogmatise upon the process of " living " among such 

 as merely the method of " trial and error." 



Some twelve months ago, while examining a specimen of 

 Hydra viridis, which had been obtained from some duck-weed 

 (Lemna) growing in a rather stagnant pond, I was interested to 



