Development of the Organic Body. i i 



separated by cutting" ; and in a third class of trials, a diluted solu- 

 tion of a lithium or a magnesium salt was added to some sea-water, 

 in which the ova were placed for a time and then returned to their 

 usual medium. In most cases all these ova proceeded to develop, 

 even those that had been mutilated ; but, so far as I know, not in 

 any instance did development proceed further than the larval form, 

 whilst others stopped short of that. 



Professor Schafer makes use of these experiments, which evi- 

 dently seem nothing- more than instances of an artificially-produced 

 parthenogenesis, to proclaim that the doctrine of "vitalism has 

 " not only had its foundations undermined, but most of the super- 

 structure has toppled over." As usual, however, in making his 

 comparisons he exaggerates matters on the materialistic side, for 

 none of the treated ova, as far as I can learn, ever reached maturity, 

 and even if they had, they would be nothing more than cases of 

 parthenogenesis. 



Development of the Organic body. 



As soon as the fusion between the two complementary repro- 

 ductive bodies has been completed, the resulting fertilized ovum 

 or egg, in all organisms alike, begins to develop. It surrounds 

 itself with a wall, probably of cellulose, which must have been 

 formed by some catalytic chemical process from the protoplasm. 

 We see, then, a simple nucleated cell which at once divides into 

 two halves by building a wall across its middle. These two cells 

 each divide again in the same way into four, and the four into eight, 

 and these again and again till a considerable tissue of cells has been 

 formed. The process in its early stages is essentially the same in 

 all organisms, whether animal or plant, but the arrangement of the 

 cells and their position in regard to each other are very various. 

 As each new division of cells is made, there arises a certain differ- 

 entiation among them which probably is caused by an alteration in 

 the character of their protoplasm. One thing is certain, to one set 

 of cells one function is assigned, and to others a different function. 

 In plants some cells are deputed to give rise to the root, others to 

 the stem, and others again to the leaves ; and each set of cells, with 

 a certain function to perform, occupies the exact place which the 

 organ produced must occupy in the developed body, in order that 

 it may perform its Work. 



