10 



BVTANT. 



perature of 30° C. to one of 30° C. ((38° to 86° Falir.), witlidra us its poeuil- 

 opodia and ceases its activity in the space of five minutes. In an hour 

 after the restoration of tlie normal temperature (20° C.) the movements 

 beirin again. If the temperature is raised to 35° C. (95° Fahr.) the 

 organization of the plasiuodium is destroyed. 



The Plasmodium uf Fuligo variana, Bonjuif. {JEtlMlium septicum. 

 Ft.), when placed in a cliamber eurnjunded by ice, contracts into a 

 rounded form and ceases all moiiou ; upon gradually raising the tem- 

 perature again the normal state is resumed. 



(d) In glycerine, a concentrated solution of sugar, a five per cent solu- 

 tion of potassium nitrate, orafive perceut solution of sodium chloride, a 

 Plasmodium contracts, and becomes rounded and motionless. A sudden 

 decrease in the concentration of the solution by vpliicli a plasiiiodium 

 is surrounded also results in a stoppage of its movements. A Plasmo- 

 dium of i)j(?y?n»«?» gerpMto, when placed in a one per cent solution 

 of potassium nitrate, and allowed time to regain its activity, suddenly 

 rounds itself up and stops its movements when the preparation is 

 washed out with distilled water ; after the lapse of a few minutes (ten 

 to twelve) the activity begins to show itself again, and in half an hour 

 the normal state is restored. 



10.— Ciliary Movement. The swimming of swarm-spores, 

 spermatozoids, and many other naked protoplasmic bodies, is 

 due to the rapid vibratory motion of extremely small whip- 

 like extensions of the hyaline portion of the protoplasm. 



Examples of ciliary movement are very common. In some swarm- 

 spores, as in those of Vauclieria, the whole surface is covered with short 

 cilia ; in others, as in (Edogonium, tlie cilia form a crown about the hya- 

 line anterior extremity ; those of Pandorina and Cladophora, and the 

 spermatozoids of Bryophytes and Pieridophytes, have two or more cilia ; 

 while the swarm-spores of Myxomycetes have but one. 



The rapidity of the swimming motion produced by cilia is consider- 

 able, as sliown by measurements made by Holmeisler* in the case of 

 swarm-spores, viz. : 



fuligo varians {JEthalium septicum). .. .7 to .9 mm. per second. 



Lyeogola epidendrum .33 mm. " " 



(Edogonium msicatum 15 to .30 mm. " " 



Vaueheria sp 10 to .14 mm. " " 



1 1 .—The Activity of Protoplasm Enclosed in a Cell-wall. 



The movements of protoplasm in closed cells differ but 

 little from those in naked ones ; the differences are such as 

 are due to the fact that in the latter case the protoplasm is 



* " Lehre von der Pflanzenzelle," p. 30. 



