BOTANY. 



differs from that of animals in its secretions. And yet these secre- 

 tions are not strictly confined to plants ; cellulose, starch, chlorophyll, 

 and other products of vegetable protoplasm formerly regarded as pe- 

 culiar to plants are now known to occur in undoubted animals. Botanists 

 and zoologists have labored long in vain to discover absolute differences 

 between the animal and the vegetable kingdoms; between the higher 

 plants and the liiglier animals there are great and constant differences ; 

 in none of the higher animals, for ex- 

 ample, is chlorophyll produced ; but. 

 in the lower orders of both kingdoms 

 not one of the differences observed to 

 hold between the higher plants and 

 --_ animals exists. 



2. The exact chemical compo- 

 sition of protoplasm has not hith- 

 erto been made out, but it is 

 known to be an albuminous, 

 watery substance, combined with 

 a small quantity of ash. It is 

 probably a complex mixture of 

 chemical compounds, and not a 

 single compound. It contains at 

 some time or another all the chem- 

 ical constituents of plants. Oil, 

 granules of starch, and other or- 

 ganic substances are frequently 

 present in it, but they are to be re- 

 garded as products rather than 

 proper constituents of pro! oplasm. 



Fig. 1. A little more than half of 



i longitudinal section of the apex of 



yonng root of the Indian corn. 



(a) Water makes up a considerable 



Tlie part above is the body of the part of the bulk of ordinary protoplasm, 

 root, that below it is the root-cap ; , . , . / 



r, thick outer wall of the epidermis; and is much more abundant in its 

 m young pith-cells; /.young wood- active than in its dormant conditions, 

 cells ; g, a young vessel ; , t, inner T , 



younper part of root-cap ; a, a, out- In the protoplasm ot fulif/o tariai.s 



er^oldir part of rootKjap.-After ( one of the S i ime Moulds) just before 



the formation of its spores there is 70 



per cent of water ; in dry seeds, on the other hand, the amount is not 

 more than about 8 to 10 per cent. 



(b) As to its molecular constitution, Strasburger holds* that proto- 

 plasm is composed of minute solid particles (not, however, of a crystal- 

 line form), separated from each other by layers of water (see Cell-wall 



* " Studien tiber Protoplasma," 1876. 



