Keegan : The Chemistry of some Commoyi Plants. 399 



soluble salts, 21.9 lime, 3.8 magnesia, 5.7 silica, 4.6 P"0^, 

 8.8 SO^, and 6.3 chlorine. The ' strong- fragrant smell 

 abounding- with a pung-ent volatile salt ' which the Mint tribe 

 evolves, is due to a volatile oil composed of derivatives of 

 the h)'drocarbon menthene C^^H^^ and chiefly of its alcohol 

 menthol C^'^H^^'OH which, combining- with acetic or other 

 organic acids, is mainly responsible for the powerful odour ; 

 another derivative, viz., ketone menthone C^^H^^O occurs only 

 in the flowers. The process by which the scent is produced is 

 called etherification, and is favoured and stimvilated by a great 

 acidity of the sap, and by any conditions (such as full exposure 

 to sunlight, dry air, elevated station, &c.), which strengthen the 

 chlorophyllic function of the leaves, and also tend to diminish 

 the percentage proportion of water in the plant. In Labiates 

 the grains of chlorophyll lie close together in a restricted space, 

 with the result that the process of deassimilation proceeds 

 quickly and the production of volatile oil is specially abundant. 

 Primrose {Primula vulgaris). — This plant, which 'on its 

 sunny bank peeps forth to give an earnest of the Spring,' has 

 challenged the attention of poets much more effectively than 

 that of scientists. And inasmuch as I am not cognisant of any 

 full chemical analysis of its constituents having appeared in any 

 European work, I may perhaps be allowed to tackle the subject 

 in some detail, merely premising that the following summary 

 refers solely to the young plant just evolved in April. The root- 

 stock as regards anatomical structure approaches that of a 

 rhizome, i.e. there is the disappearance of fibres and other 

 supporting apparatus, the appearance of starch (the cells of the 

 cortex are crowded with large granules), the augmentation of 

 the cortical parts, and the reduction of the pith ; it contains no 

 tannin, and very little or no mucilage, mannite, or glucose, but 

 there is a small quantity of a saponin-like glucoside called 

 cyclamin C'^'^H^^O^^ which is a typical hasmolytic (blood- 

 corpuscle dissolving) agent producing local coagulation of 

 fibrin, and thrombosis when introduced into the blood ; there 

 is also a sugar which yields levulose by dilute acids, and 

 1.5 per cent, in dry, of a heptatomic alcohol called volemite 

 CH^'^O^ by Bougault and AUard. The very young smallish 

 leaves contain 2.6 per cent, of a white pasty wax (pseudo- 

 stearoptene), but very little carotin, and no fat or resin ; the 

 amount of chlorophyll is unusually large ; there is only a very 

 little quercitrin, its place being taken apparently by cyclamin ; 

 there is abundant pectosic mucilage, but only a little sugar or 



1906 November i. 



