THE PLANT-CELL 39 



A number of the metals Lead, Copper, Silver, and several others 

 are also occasionally met with. 



The extraordinary complexity of the compounds which make up 

 the protoplasmic mass may be illustrated by the formula for Albu- 

 men (CjoHnaNuOso). The result of an analysis of the plasmodium 

 of a Slime-mould (jfflihalium septicum) showed 71.6% water, and 

 28.4% solid matter. The latter was composed of 30% of nitrogenous 

 compounds : plastine, vitelline, myosine, pepsine, lecithine, guanine, 

 sarcine, xanthine, and ammonia carbonate; 41% was composed of 

 ternary compounds, including paracholesterine, resin, and a yellow 

 pigment, sugar (non-reductive), various fatty acids, and neutral fatty 

 substances. The remainder was composed of mineral substances, 

 including calcium combined with various acids, phosphates of potas- 

 sium and magnesium, and chloride of sodium. While this probably 

 does not represent the constitution of the ordinary protoplast, it 

 illustrates the extraordinary complexity of the protoplast, and the 

 impossibility of obtaining more than an approximation of its chemi- 

 cal composition. 



Physiological Properties of Protoplasm 



Protoplasm being the essential living part of all organisms, it is 

 in the protoplasm that the peculiar physiological properties of living 

 things reside. These properties are motility, nutrition, respiration, 

 irritability, adaptability, and reproduction. 



Motility. Whether the protoplasm occurs as a naked protoplast, 

 or whether it is enclosed within a membrane, one of its most marked 

 characters is its power of spontaneous movement. This is espe- 

 cially marked in such naked protoplasts as an Amoeba or zoospore. 

 In the former, movement of the whole mass is effected by the pro- 

 trusion of arms or pseudopodia, which is followed by the contraction 

 of the rest of the mass, resulting in a slow creeping movement by 

 which it progresses. Such a movement only takes place when the 

 protoplast is applied to a solid surface. The amoeboid movement 

 involves two kinds of movement, the extension of the outer hyalo- 

 plasm, of which the pseud opodium is at first composed, and second, 

 a rapid streaming of the softer granular plasma into the extended 

 pseudopodium. The amoeboid movements serve two purposes, the 

 shifting of the position of the protoplast, and the ingestion of solid 

 food, which is surrounded by the extended pseudopodia and thus 

 taken into the protoplast. 



Ciliary Movement. Small naked protoplasts more commonly show 

 another type of movement, the ciliary movement. Ciliated cells 

 are very common among the lower organisms, Bacteria, Infusoria, 

 and Algae, but also occur in higher ones ; e.g. the spermatozoids, or 



