The Distribution of Oxydases in Plants, etc. 



215 



stration not only of the presence but also of the distribution of oxydases in 

 such delicate tissues as the petals of flowers. 



Further, as will be apparent to all students of Genetics, the application of 

 precise chemical methods to the investigation of the distribution of oxydases 

 in plant- and animal-tissues is of special importance at the present time. 

 For, thanks to the work of Bateson, Baur, Gregory and many others, not only 

 do we possess a detailed knowledge of the modes of inheritance of flower- 

 colour in many different species of animals and plants, but we have also at 

 our disposal many pure-bred strains of animals and plants, the genetical 

 relationships of which are known. Therefore we may hope that precise tests 

 applied to plants or animals of known genetical constitution may throw new 

 light on the physiological roles of oxydases in the organism and may con- 

 tribute also to an understanding of the nature of Mendelian characters, the 

 sum total of which appears to determine specific character. 



The method which we employ consists in the treatment of a tissue with the 

 colour-indicator constituent of the oxydase reagent together with a " hormone " 

 (see H. E. and E. F. Armstrong, 1910, 1911), that is a substance which 

 causes the plasmatic membrane to become permeable to the reagent and also 

 renders active the oxydases and other enzymes present in the cell. When 

 this component of the oxydase reagent is added to the intact petals of a flower 

 the first visible effect is the decolorisation of the flower. As soon as the 

 colourless state has been induced, the second component of the reagent, 

 hydrogen peroxide, is added. Owing to the previous treatment of the tissues 

 the hydrogen peroxide penetrates rapidly into the cells and the colour- 

 reaction indicative of oxydase is produced, generally in the course of a few 

 minutes. By the use of various oxydase-indicators, «-naphthol, benzidine and 

 others, we have been enabled to establish the following facts with respect to 

 (1) the distribution of oxydases in the Chinese primrose (Primula sinensis) 

 and (2) the relation between oxydases and pigment formation in that 

 plant : — 



1. The distribution of pigment in the flower coincides exactly with that of 

 a peroxydase. 



2. The alcoholic solution of the oxydase-indicator brings about decolorisa- 

 tion of the flower. In most cases the decolorisation is rapid and complete ; 

 but in certain colour-varieties the flower-colour is more resistant. Surface 

 sections of such flowers may however be readily decolorised. The colourless 

 state is maintained till hydrogen peroxide is added. Hence the oxydising 

 agents present in the flower in Primula sinensis are to be regarded as 

 peroxydases. 



3. The use of different oxydasic reagents reveals the presence of two 



