732 THE POPULAR SCIENCE MONTHLY. 



stem commencing at some distance above the point to which the stroke 

 had been applied ; its strength appears to have here suddenly left it ; 

 it is no longer able to bear its own weight, and seems to be dying. 

 The protoplasm, however, of its cells, is in this instance not killed, it 

 is only stunned by the violence of the blow, and needs time for its res- 

 toration. After remaining, it may be for some hours, in this drooping 

 and flaccid state, the stem begins to raise itself, and soon regains its 

 original vigor. This experiment will generally succeed well in plants 

 with a rather large terminal spike or raceme, when the stroke is ap- 

 plied some little distance below the inflorescence shortly before the 

 expansion of the flower. 



In the several instances now adduced, the protoplasm is in the ma- 

 ture state of the plant entirely included within a wall of cellulose. 

 Some recent beautiful observations, however, of Mr. Francis Darwin 

 have shown that even in the higher plants truly naked protoplasm may 

 occur. From the cells of certain glandular hairs contained within the 

 cup-like receptacles formed by the united bases of two opposite leaves 

 in the teasel (Uipsacus), he has seen emitted long, pseudopodia-like 

 projections of the protoplasm. What may be the significance of this 

 very exceptional phenomenon is still undetermined. It is probably, as 

 Mr. Darwin supposes, connected with the absorption of nitrogenous 

 matter. 



That there is no essential difference between the protoplasm of 

 plants and that of animals is rendered further evident by other motor 

 phenomena, which we are in the habit of regarding as the exclusive 

 attribute of animals. Many of the more simply organized plants give 

 origin to peculiar cells called spores, which separate from the parent, 

 and, like the seeds of the higher plants, are destined to repeat its form. 

 In many cases these spores are eminently locomotive. They are then 

 termed " swarm-spores," and their movements are brought about, 

 sometimes by changes of shape, when they move about in the manner 

 of an Amoeba, but more frequently by minute vibratile cilia, or by 

 more strongly developed flagella or whip-like projections of their pro- 

 toplasm. These cilia and flagella are absolutely indistinguishable from 

 similar structures widely distributed among animals, and by their 

 vibratory or lashing strokes upon the surrounding water the swarm- 

 spores are rapidly carried from place to place. In these motions they 

 often present a curious semblance of volition, for if the swarm-spore 

 meet with an obstacle in its course, it will, as if to avoid it, change the 

 direction of its motion, and retreat by a reversion of the stroke of its 

 cilia. They are usually attracted by light, and congregate at the light 

 side of the vessel which contains them, though in some cases light has 

 the opposite effect on them, and they recede from it. 



Another fact may here be adduced to show the uniform character 

 of protoplasm, and how very different are its properties from those of 

 lifeless matter, namely, the faculty which all living protoplasm possesses 



