THE VITAL PROPERTIES OF THE CELL 147 



with this original material, and thus to produce quaternary com- 

 pounds. 



It is as yet impossible to say what chemical processes occur in 

 the green protoplasm, when, under the influence of the sun's vital 

 energy, carbon dioxide and water are taken up, and oxygen is 

 given off. The first product of assimilation, which can be 

 definitely made out, is starch, or perhaps, as a preliminary stage, 

 sugar. It is almost inconceivable that either of these could be 

 formed by a direct synthesis of carbon and water ; apparently a 

 number of intermediate substances are formed during the course 

 of a complicated process. " Indeed, it is not impossible," as Sachs 

 (IV. 32a) remarks, " that certain closely-connected constituents of 

 the green plasma themselves participate in the process ; that, for 

 example, the molecules of the green protoplasm become split np, 

 and that certain atoms are given up and others substituted for 

 them. The theory has a certain degree of probability from the 

 observation that in many, though not all cases, the mass of 

 chlorophyll substance gradually decreases, and finally quite dis- 

 appears, whilst the starch granules which it contains become 

 larger and larger." 



The carbo-hydrates (starch) which, by means of the chloro- 

 phyll function, have accumulated in the body of the plant, form 

 the material which is converted in the protoplasm into the 

 vegetable oils. The ternary non-nitrogenous, organic compounds 

 supply further the basis for the synthesis of quaternary albumin- 

 ous substances, and thus assist in the completion and increase of 

 the protoplasm. However, for these processes, nitrates and sul- 

 phates are necessary, and these are obtained by the plants from 

 the earth by means of their roots. 



That proteid substances can be formed by the living cell out of 

 such material has been experimentally proved by Pasteur. He 

 cultivated low Schizomycetes, such as Mycoderma aceti, Yeast, etc., 

 in artificially prepared nutrient solutions. Thus he showed that 

 Mycoderma aceti can multiply actively in the dark, if only a few 

 cells are placed in a nutrient solution, composed of a salt of 

 ammonia, phosphoric acid, potash, magnesia, water, and alcohol or 

 acetic acid of suitable strength. Hence the fungi cells, if they 

 have multiplied to a considerable extent, must have formed proteid 

 materials by means of the decomposition of these substances, in 

 addition to cellulose and fats. 



Thus plants, which by means of their chlorophyll produce carbo- 



