THE IXCO:\i PLETJi 47 



several of the older writers, reliable in man}^ respects, 

 liave spoken in praise of tlie culinary qualities of the 

 rhubarb leaf-blade. With regard to the second point, 

 we find in the famous Herhall of Gerard the name of 

 Hippolajxtthitvi sativuTYi or Munkes Ritharbe, Avhich 

 he describes as a " holsome potherbe". This plant is not 

 a Rhubarb but a Dock, and has been referred by experts 

 to Runcex Patienta, a dock from Southern Europe. But 

 the evil has been done in that the name "Rhubarb" 

 has been associated with the term "holsome potherbe". 

 Again, "Monk's rliubarb" appears in Syme's edition of 

 EiKjlish Botany for Riiviex alpinios, which is also a 

 Duck, It is not, therefore, surprising that the idea 

 should be prevalent that rhubarb leaf-blades could be 



eaten with impunity. 



With regard to the difference in the character of the 

 stalk as compared with the leaf, the problem is one 

 which can be settled by a consideration of the nature 

 of the blade's activity. It has been stated that sugar 

 is formed in the green parts of plants. Now in the 

 multifarious activities which subsequently take places 

 the production of oxalic acid is a feature in the meta- 

 bohsni of most, if not all, green plants. It may arise by 

 the oxidation of the sugar that is formed in the leaf, or 

 by the decomposition of the proteins. In the Rhubarb 

 its formation is more abundant than in most other plants. 

 Now, the presence of oxalic acid is a source of danger to 

 the plant itself, and for that reason a plant does not 

 thrive unless some substance like lime is presented to it 

 to neutralize this oxalic acid, and cause the formation 

 of a neutral substance like calcium oxalate. The last- 

 named substance is carried away in solution. If the 

 oxalic acid enters into combination^ not with calcium," 

 but with another somewhat similar substance, namely 

 potassium, the formation of the higlily poisonous bin- 



