MANUFACTURE OF ORGANIC FOOD 43 



of chloroplasts in its cells, quite as green as any plant, 

 and behaves, from the nutritive point of view, exactly 

 like a green plant. Some forms allied, though dis- 

 tantly, to Amoeba, to which we have referred above, 

 also possess chlorophyll as do also some of the lower 

 worms. It does not affect the physiology of the 

 process whether these green par- 

 ticles are, as some biologists have 

 attempted to show, plants living 

 in intimate association with the 

 animals in question, or, actual 

 constituents of the animal itself, 

 i.e., not introduced from without. 

 Let us examine a chloroplast 

 from the cell of a leaf. What is 

 it made of, and how does it 

 operate ? In the first place, we 

 may note that although some 

 plants have chloroplasts in the 

 forms of bands, stars, &c., in the 

 vast majority of cases the chloro- 

 plasts are minute ovoid bodies, . 



i ' FIG. 16. 

 occurring singly or in large 



numbers in the cells which con- 

 tain them (Fig. 16). Each con- 

 sists of a basis of protoplasm permeated by an 

 oily matter in which the chlorophyll, or pigment 

 proper, is dissolved. The chloroplast is, further, in 

 intimate relation with the protoplasm of the cell. 

 Chemically, the pigment which can be extracted 

 from the plastid by means of alcohol, ether and a 

 variety of similar substances, is of extremely complex 

 composition ; indeed, it is probable that it is a mixture 

 of several compounds. This apparatus does not 

 perform its function of manufacturing organic sub- 



Plant cells 

 with chloroplasts. 

 ( x 300.) 



