72 THE BIOLOGY OF DAILY LIFE. 



natural boundary at all between the animal and 



V 



vegetable kingdoms, they are separated only by 

 artifice. But I must give the very words, or the 

 reader will think I am imposing on him. 



" Protoplasm, simple or nucleated, is the 

 formal basis of all life. It is the clay of the 

 potter, which, bake it and paint it as he will, 

 remains clay separated by artifice and not by 

 nature, from the commonest brick or sun-dried 

 clod" (p. 129). 



Animal and vegetal seem separated only by 

 artifice and not by nature, when that mischievous 

 Puck called the protoplasm-hypothesis squeezes the 

 juice of his "Love in Idleness" into the eyes of the 

 Leaders of physiological thought and makes natural 

 confusion worse confounded. 



In immediate connection we have a very remarkable 

 instance of the mental confusion, which this theory 

 engenders. I shall call it the " Calc-spar fallacy," 

 and first explain what I mean by this expression, its 

 suitability may then be left to the reader. 



If you take a crystal (rhombohedron) of calc-spar, 

 and look through it a mark such as " /" you will see 

 it as " //." Of course it exhibits the phenomenon of 

 double refraction ! Gentle reader, pity my simplicity, 

 and let me finish my very simple little illustration in 

 peace. I am not going to bore you with mathematics, 

 at least not beyond simple or compound addition in 

 arithmetic. 



Have you ever reflected that there may be as 

 Macbeth does not say " a calc-spar of the mind ?" I 

 mean that the very ablest and acutest minds may 

 exhibit the phenomenon of double refraction. I am 



