36 CELL INTELLIGENCE THE CAUSE OF EVOLUTION 



while others go in opposite directions and many, if not 

 the majority, are indifferent to light. It is an easy matter 

 to make the negatively heliotropic or the indifferent 

 (copepods) almost instantly positively heliotropic by add- 

 ing a small but definite amount of carbon dioxide in the 

 form of carbonated water to the water in which the ani- 

 mals are contained. If the animals are contained in 50 

 C. C. of water, it suffices to' add from 3 to 6 C. C. of carbon 

 in water to make all the copepods energetically positively 

 heliotropic. This heliotropism lasts about half an hour, 

 probably until the carbon dioxide has again diffused into 

 the air. Similar results may be obtained with any other 

 acids." 



I would like to ask what any man would do under sim- 

 ilar circumstances if he was in a room and someone filled 

 it with a poisonous or irritating gas? Would he not also 

 at once become "energetically heliotropic" and attempt 

 to escape from the room? Would he not also lose his 

 heliotropism as soon as the noxious gases had passed out 

 of the place where he was confined? I think he would in 

 precisely the same manner as these cells, which are called 

 copepods. The cell is an animal that feels, feeds and per- 

 forms all the functions of life in every manner similar to 

 that of Mr. Loeb. The advocates of the chemical theory 

 of life base their strongest proof on this point of helio- 

 tropism, which is entirely without foundation. I do not 

 think it is necessary to go into any further detailed dis- 

 cussion of the other tropisms like galvano-tropism and 

 geo-tropism. The first is the idea that some cells are 

 affected by electricity, the other that they are affected by 

 the force of gravity. While it may be said they are af- 

 fected, still they are affected in no wise different from our- 

 selves. They will take advantage of the electric force 

 and turn it to their own purpose similar to ourselves. For 



