42 ENDOWMENTS OF BIOPLASTS 



gous process." But natural inferences and analogical 

 arguments of this kind do not forward natural know- 

 ledge. The perfection of an optical instrument by 

 experiments conducted by man in dayhght surely 

 throws marvellously Kttle light upon the question of 

 the formation of an eye in darkness, altogether 

 without man's agency. 



We have seen that, as development proceeds, the 

 original mass of simple living matter gives rise, by 

 growth and subdivision, to multitudes of descendants, 

 which succeed one another in regular order until at 

 last a number of bioplasts result, which take part in 

 the formation of tissues differing remarkably from 

 one another in properties, and organs whicb per- 

 form very different kinds of work, duty, or function. 

 But all the difierent tissues and organs are supplied 

 by vessels and all nourished by the same blood. By 

 the agency of bioplasm, however, very different sub- 

 stances are produced, although the elements of all are 

 derived from the same blood. Thus, saliva, gastric 

 juice, hile, and urine have very few properties in 

 common; they are secretions, having very different 

 chemical composition and properties, and perform 

 very different offices. Tet they are all formed from 

 the blood by different kinds of living matter. It is 

 very remarkable that all these bioplasts which have 

 resulted by descent from the same original mass should 

 possess endowments as different from those of the 

 original parents of them all as they are from one 

 another. 



'No adequate explanation has ever been given of 

 this fact. It will be found upon examination that all 

 the explanations that have been offered only amount 

 to statements of the fact itself in a somewhat round- 

 about way. Nor can the formation of tissue be ade- 

 quately accounted for. Form and structure result 

 from the formless and structureless, but to attribute 



