THE ORGANIC ELEMENTS. 23 



of the forms of wax have not been sufficiently examined. According 

 to the first formula, 10 equivalents of starch (0120 H 100 O 100) 

 forms 3 equivalents of wax (C 120 H96 O30), with the loss of 2 HO 

 and 66 O. According to the second formula, 5 equivalents of starch 

 + 10 HO = C 60 II 60 O 60, which, by losing 56 O, is converted into 4 

 equivalents of wax, C 60 H 60 O 4. 



10. Another class of substances is found in plants, which 

 neither exist in the cell-walls, nor are the cell-walls formed from 

 them, but nevertheless their presence is necessary for the simplest 

 processes of vegetation. They are composed of Carbon, Hydrogen, 

 Nitrogen, and Oxygen, to which are sometimes added Phosphorus 

 and Sulphur. I call them by the collective name Mucus ( Schleini) ; 

 the chemists give them various names, as Albumen, Gluten, Gli- 

 adin, Zymom, Gelatin, Diastase, Gluten vegetabile, Legumin, &c. 



In all the vital cells of plants, besides the substances mentioned in the 

 last section, there is found a semi-fluid or liquid granular matter, of a pale 

 yellow colour, sometimes entirely fluid, sometimes solid, and which, 

 through the action of alcohol, becomes entirely granular, fibrous, or semi- 

 membranous; which is coloured dark brown by iodine; and which, ac- 

 cording to all observation, is a multiform, changeable substance. Many 

 modifications of this substance have been separated from plants by 

 chemists, to which they have given the above names, but which are 

 perhaps seldom pure, and often formed during the process of separation. 

 All of them are characterised by the possession of nitrogen, and also by 

 their action (11.) on the previous substances (9.). They are sparingly 

 present, or are absent altogether, in those parts of plants which contain 

 starch, and which do not easily pass into fermentation, as the tubers of 

 the potato, the fruit of the rye, and the rootstock of the arrow-root plant 

 (Mara?ita arundinaced) ; but in parts of plants which easily ferment 

 they are found in large quantities, as in good wheat, the juice of the 

 grape, &c. 



In the youngest cells of plants, the mucus (Schleim of Schleiden ; pro- 

 tein of chemists *) presents itself as a slight covering over the whole inner 

 surface of the walls of the cells. (See this work on the Motion of the Sap 

 in Cells.) In the seeds of Legummosa, this substance is found in the 

 same cells which contain starch, but in smaller and larger quantities 

 in especial cells, and sometimes apparently filling them entirely. Thus, 

 in the grains of the Cerealia, the layer of cells immediately under the 

 coats of the seed are almost exclusively filled with the mucus, whilst the 

 remaining cells of the albumen (perisperm) contain starch, with only a 

 small quantity of mucus. In the seeds of the almond, the mucus is 

 mixed with oil; but bitter and sweet almonds, under the microscope, 

 exhibit no essential difference. 



Modern chemistry, in consequence of the labours of Liebig and Mulder, 

 divided the forms of mucus into three principal groups : into Albumen 

 (vegetable albumen), Fibrin (gluten of the Cerealia), and Casein 

 (leguinin of peas and beans), and which are regarded as identical with 

 the substances of the same name found in the animal kingdom. Dumas 

 regards as a fourth group Gelatin (gelatina animalis), which should be 

 regarded as a part of the composition of gluten. Mulder has pointed out 

 that these compounds have all a common basis (H31 C 40 N 10 O 12), 



* Frotoplasma of Mulder and others. TRANS. 

 c 4 



