Manchester Memoirs, Vol. lix (191 5), No. 11. 39 



become visible. In other words, each individual only 

 shows us a part of his innate attributes ; it is as though 

 the latent potentialities (germs) did not exist. Numerous 

 experiences have taught us that the appearance of these 

 innate attributes depends in a large degree on the con- 

 ditions of existence. Under certain conditions this talent 

 (attribute) becomes visible, and that remains latent, whilst 

 under other conditions other talents (attributes) will 

 appear or will remain hidden. 



We see, for example, that the leaves of the tree known 

 as the copper-beach have a red of reddish brown colour. 

 But this colour only appears under the influence of ordi- 

 nary light. In shadow the leaves become green, the 

 characteristic colour of the species disappears almost com- 

 pletely (in deep shadow completely). 



We all know the large floating leaves of the water 

 lily. These leaves only acquire their characteristic ap- 

 pearance when they can float on the surface of the water. 

 If it is too deep for them to reach to the surface, they 

 become thin, transparent, more or less shrivelled : they 

 are unrecognisable and seem to belong to another species. 

 May the water level fall, the floating leaves appear. 



The pretty white flower called Edelweiss, which 

 adorns the high mountains of the Alps and the Pyrenees, 

 undergoes a profound change when it is cultivated on the 

 plains, where the conditions of existence are different. 

 The pretty shape of the plant disappears and the flowers 

 become greenish, 



One of the most remarkable instances of such a 

 change is the following. In certain caves where no ray of 

 light has ever penetrated, there exists a species of Sala- 

 mander called Olm. This animal has no eyes. But when 

 it is exposed to the light (with certain precautions), an 

 incredible transformation is apparent. The ryes appear 



