The Message of Science. 91 



It is at the price of all this auxiliary labor and only by 

 virtue of it that the brain and muscle cells are nourished 

 and are able to live so long and do so much in the way of 

 locomotion and intelligence. Mind would be impossible 

 on a poorer food for the brain cells. 



And what is the lesson from this ? Locomotion, intel- 

 lect and a lifetime of a century have been attained by the 

 metazoic . cell from a food as good as that which now 

 comes to them in the blood plasma. Yet that plasma still 

 contains noxious particles, despite the efforts of the living 

 organs which labor to refine and improve it. The infer- 

 ence is easy. Science must come to the aid of the organic 

 apparatus and furnish a food clean, pure and easier of 

 assimilation. 



This brings us to the fundamental question. What is 

 food ? — -a question which has been variously answered. 

 Nor can it be answered at present. Food is that which 

 renews the cells ; and the cells absorb it from the plasma 

 of the blood ; but exactly what portion they absorb, or 

 how much of what they absorb is necessary or best for 

 this renewal, is not known. There is doubt whether the 

 tissue cells are renewed as to their intimate structure or 

 that nutrition, at bottom, adds ponderable matter to the 

 cell, or is more than a replenishing of ions. We do not 

 know that cell food is, or need be, anything more gross 

 than ions or electrons. That is to say, the idea has be- 

 gun to prevail, that nutrition as we now know it is an 



