SUGGESTIONS FOR RELIABLE HYPOTHESES 181 



(a) From the outset it is improbable that from the 

 beginning there were organisms which, for the preserva- 

 tion of their individual life, were dependent upon the 

 separate vital functions of others, since they themselves 

 lack the capacity of performing them alone. 



The fungi plants, generally speaking, can no longer 

 assimilate, and thus cannot fulfil the task which falls 

 upon the plant kingdom taken as a whole. To the 

 existence of an animal there appertains free locomotion 

 and the formation of sense organs ; the animal Parasites, 

 however, often dispense entirely with both, with the 

 exception perhaps of feelers. 1 Multicellular animals 

 have also their special functions in contrast to the 

 unicellular transferred to separated tissues (organs) ; 

 many Parasites which, in addition, in their total 

 habit belong to the Worms or the Crabs, i.e. to fairly 

 differentiated organisms often lack even an intestinal 

 system of their own. 



(b) Had there been existent from the beginning 

 Parasites of the present form and mode of existence 

 there would have resulted, at least in some cases, very 

 singular consequences. We know Parasites which must 

 live not only in one particular species of animal, but 

 often even in one particular organ. The worm Oxyuris 

 vermicularis can only live in man with him and in 

 him must it also have been created. The Trichinse 

 can only maintain life in cross-fibred muscles. A larval 

 form (oncosphcera) of the tapeworm (tcenia ccenurus) 

 can only develop itself further in the brain and spinal 



i R. Hertwig : Lehrbuch der Zoologie, p. 155. 



