74 



THE MECHANISM OF LIFE 



birds. Many tissues have this lined or striated structure and 

 exhibit interference colours like those of the periodic precipi- 

 tates, their structure showing alternate transparent and opaque 

 lines, whose width is of the order of a micron. This is the 

 structure of muscle, and to this striated surface is also attribut- 

 able manv of the most beautiful colours of nature, the gleam 

 of tendon and aponeurosis, the fire of scarab and beetle, the 

 colours of the peacock, and the iridescence of the mollusc and 



Fig. 17- — Photomicrograph of striated structure 01 a periodic precipitate of 

 carbonate and phosphate of lime (magnified 500 times). 



the pearl. The study of liquid diffusion has given us an idea 

 of the physical mechanism by which these striated tissues are 

 produced, a mechanism which up to the present time has not 

 been even suspected. Our experiments show how readily such 

 striped or ruled structures may lie produced in a colloidal 

 solution by the simple diffusion of suits such as are found in 

 every living organism. 



To make a spectroscopic grating by diffusion we proceed 

 as follows. We take 5 c.C. of a 10 per cent, solution of 

 gelatine, and add to it one drop of a concentrated solution 



