THE EVOLUTION OF LIFE AND MIND 75 



no distinction of nucleus and cell-body, and they built up 

 their plasm directly out of inorganic matter by the natural 

 " imbibitional energy " which was a consequence of their 

 loose texture and their large proportion of carbon and water. 

 Animal organisms could only appear when there were already 

 vegetal organisms to feed on. In the course of time the 

 hereditary matter would concentrate in security at the centre 

 of the globule of plasm ; we should have nucleated cells. 

 The mechanical strain outwards of the loose plasm towards 

 contiguous particles of food would induce the formation of 

 temporary folds or projections; we should have the first 

 organs of locomotion, the first rhizopods. The mechanical 

 strain on the surface particles would lead to the formation 

 of a protective membrane, and the loose flow of the plasm 

 into temporary arms or legs would have to be replaced by 

 permanent threads or hairs or lashes (cilia), with which the 

 water could be struck as with oars ; we should have the 

 first infusoria. Meantime, the principle of aggregation 

 would be steadily at work, and loosely individualised clusters 

 of cells (of which many live to-day) would be formed. 

 Each cell would live its own life ; it would be forced to the 

 surface of the cluster, and the centre would be hollow. An 

 intenser absorption of the food-bearing stream of water at 

 one spot would make an indentation at that spot, and the 

 ball would in time double upon itself (we have very strong 

 proof in embryology that this was the next step). Thus we 

 should have a primitive stomach and a primitive mouth. 

 Motion through the water would lengthen the body, make 

 it evenly bilateral, and give it a definite head and tail (as 



