24 THE GENERAL CHARACTERS OF CELLS, BY S. STRICKER. 



spherical for hours, without losing their vital properties, as may be 

 seen in the case of the salivary corpuscles, is also in favour of it. 



The coalescence of the spherical cells described by Briicke, Neumann, 

 and Golubew, can then be very naturally explained ; for it may be said 

 that, as a consequence of the stimulus, the opposing influences are 

 diminished, and the protoplasm now follows the laws of ordinary 

 liquids it forms drops, and these coalesce. The act of bursting in 

 water must, then, be regarded as due to a suddenly produced partial 

 coagulation resulting from the more energetic action of the fluid. 



If to the medium in which the spherical cells are contained 

 a one-half per cent, solution of common salt is gradually added, 

 the protoplasm resumes its apparent activity, and recommences 

 the usual changes of form. But if the solution added be con- 

 centrated, the cells shrink up. It has not been, as yet, accu- 

 rately ascertained what strength of solution is compatible with 

 the life of the cells, nor for what length of time the action may 

 be continued. The proportion of water in many protoplasmic 

 substances may undergo great variations without destruction 

 of life. The myxomycetse can even be completely dried up, 

 and yet when again moistened may continue to live. 



Max Schultze and Ktihne have observed similar results 

 to those above described, to result from the action of water 

 after the addition of very dilute acids and alkalies. 



An elegant experiment has been made by Kuhne,* showing 

 the influence of gases on the movements of protoplasm. He has 

 pointed out that the ciliated cells of the gills of Anodonta cease 

 to lash in hydrogen and in carbonic acid, but that it is only 

 requisite to admit atmospheric air in order to effect the re- 

 establishment of the movements. This experiment shows that 

 carbonic acid acts injuriously like other acids. 



Weak alkaline reaction in the fluid in which the cells are 

 contained, is favourable to their movements, but acids tend to 

 arrest them. 



The contractility of the protoplasm is of the greatest im- 

 portance to the entire organism to which it belongs, for ciliary 

 movement depends upon it. 



* Max Schultze's Archiv, Band ii. 



