86 



THE MECHANISM OF LIFE 



of the crystal is a square with well-marked outline. At each 

 corner of this square there is a straight line at right angles to 

 the diagonal, which will form the sides of the crystal in process 

 of formation. From the middle of each side arise yet other 

 perpendiculars, which in their turn bear other cross lines, each 

 new line being set at right angles to its predecessor. A later 

 stage of crystallization is shown in Fig. 27, where the two 

 squares one inside the other at an angle of 45° are clearly 

 indicated. 



Fig. 2S. — Three crystals of sodium chloride in process of formation, each in 

 the centre of a field of crystallization. 



Every crystallizable substance gives a different characteristic 

 field of crystallization. In 1903, at the Congress of Angers, 

 I terminated mv address by these words: "The field of 

 crystallization may serve to determine the character of a 

 substance in solution." I have subsequently received from 

 Carbonell v Soles of Barcelona an interesting work on this 

 subject, which he contributed to the International Congress 

 of Medicine at Madrid in 1903, entitled Application </< la 

 crystalogenia experimental a la investigation toxicologka de 

 cos alcaloides. 



