-b llli: .loLKNAI, UF iJUTAXV 



This chemic'iil knowledi^e is accumulating rapidly. We know that 

 the mother substance of the anthocyanin pigment is a flavour. There 

 is evidence that either oxidation or reduction or both are concerned in 

 the production of the pigment, and if we accept Willstatter's and 

 Everest's conclusions we must regard the pigment, e. (j. in the Corn- 

 flower, as a glucocide. In the free state it is purple, in the presence 

 of acids it yields a red pigment, and when it fonns a salt with an 

 alkali — with i)otash for example — it becomes blue. 



It is not, however, easy to reconcile Willstatter's conclusions with 

 all the known genetical or even chemical facts ; but, on the other 

 hand, it is not "impossible to form a mental scheme which might 

 harmonize them. Assume that the anthocyanins are produced in 

 special " vacuoles," and assume further that the fundamental purple 

 pigment escapes from these vacuoles into the cell-sap. Then if the 

 sap be rich in organic acids the purple will change to red ; if, on 

 the other hand, the sap contains a large amount of potassium salts the 

 ])urple will change to blue. In support of an h^^Dothesis — which it 

 should be stated must be charged upon the reviewer and not on the 

 author — it may be mentioned that Pick, or some other contemporary 

 of the present writer, published evidence in support of this " special 

 vacuole " cloistering of anthocyanin pigments, and, moreover, in early 

 stages of ])etal formation in the Chinese Primula, the anthocyanins 

 may be seen as small droplets sharply marked o:ff from the geneml sap. 



vSuch an hy])othesis would, moreover, help to explain the curious 

 facts of correlation between colour and constitution : the association in 

 Stocks of hoariness of leaf with colour of flower, the superiority 

 in riavour of yellow over red-skinned tomatoes, the Aveakliness of 

 certain albinos and the coarse flavour of red as compai'ed with 

 ordinary cabbages. Evidentl}^ colom* is but an outward sign of an 

 inward grace. 



Miss Wheldale has performed a laborious and difficult task with 

 remarkable skill and judgement. Although she herself has done inucli 

 to elucidate the genetical behaviour and chemical nature of the antho- 

 cyanins, she has, nevertheless, brought to her work a detached and 

 judicial mind. As a result her pages do not smell of the laboratory 

 nor savour of specialized pedantry : and what praise higher than this 

 can be bestowed on records of contemporary research r' 



F. K. 



BOOK-NOTES, NEWS, Etc. 



At the meeting of the Linnean Society on November 16th, 

 Dr. H. Daydon Jackson gave an account of the Codex Anicice JiiUance 

 in the lm])crial Libniry at Vienna, of which a copy in collotype was 

 lat^'ly jjrescnted to the Society by Sir Frank Crisp. Pedanios (or 

 l*edakios) Dioscorides was born at Anazarba in Cilicia, and received 

 his education at Tarsus and Alexancb'ia. Details of his life are 

 wanting, but it seems certain that he was physician to the Poman 

 legions, and accompanied them into nearly every country on the north 

 of the Mediterranean. He was a contemporary of Pliny the elder. 



