No. 520] BASIS OF MENDELIAN PHENOMENA 209 



calyx the increased pigment production is a heritable 

 character, and therefore the change which brought it 

 about must have been of a fundamental sort, in the germ 

 plasm. 



A more recently developed hypothesis of anthocyan 

 formation, suggested by Pick in 1883 and supported by 

 the work of Palladin ( '08), Buscalioni and Pollacci ('04), 

 in their extensive memoir, and others, is that anthocyan 

 originates from the action of oxydases upon the respira- 

 tory chromogens of the cell, the latter being aromatic 

 bodies which on oxidation yield colored compounds. The 

 experiments of Molliard ('09) support the latter theory 

 by showing the necessity for the presence of oxygen in 

 anthocyan production. Molliard also showed that, when 

 grown in a sugar solution, the respiratory exchanges of 

 plants are more intense. 



Combes ('09??) has recently harmonized the two 

 theories. He shows that there is a close relation be- 

 tween the production of anthocyan and an increase in 

 the proportion of sugars and glucosides in the cell sap. 

 He concludes that since the formation of anthocyan, a 

 compound of glueoside nature, is correlative with an in- 

 crease of the total glucosides, the anthocyan cannot be 

 formed from preexistent glucosides, but from some other 

 source; and since there is also an increase in chromogens 

 (Palladin) therefore anthocyan is not derived from 

 chromogens already existing, but its formation must be 

 provoked by the accumulation of sugars, which increases 

 the respiratory exchanges and appears to determine the 

 acceleration of oxidation processes. Under these condi- 

 tions the production of glucosides is increased, and these 

 are, in part at least, anthocyanins. 1 



It is scarcely necessary to point out that, whatever may 

 be the chemistry and physiology of anthocyanin produc- 

 tion, in the case of (Enothera rubricalyx there must have 

 been a fundamental change in the germ plasm by reason 



