ON PUOTRUSION OF PROTOPLASMIC FILAMENTS. 265 



C( l!-\vall of one of the Iiigher plants. But the balance of pro- 

 babilities is reversed when we inquire into the causes that induce 

 the movements. For it is inconceivable that violent contraction 

 should be mechanically or chemically produced by such different 

 reagents as very dilute acids, alkalies, solutions of chloride of gold, 

 sul|)hate of quinine, camphor, or by a temperature below 57° C. 

 On the other hand, the whole behaviour of the filaments 

 (except the results of irrigation with alcohol) points to the 

 conclusion that the movements are connected with living matter. 

 In this point of view the more important features in the beha- 

 viour of the filaments are the following : 



1. The "spontaneous" movements. 



2. Contraction being produced by various reagents, such as 

 acetic acid or sulphate of quinine in very dilute solutions, and 

 by the vapour of chloroform. 



3. Death in an extended or not fully contracted condition 

 being produced by solutions of osmic acid and acetate of 

 strychnine. 



4. Contraction being produced by subjecting the filaments to 

 a temperature below 57° C. ; to the action of the induced 

 current ; to mechanical violence. 



5. Not only do these agencies cause contraction, but 

 the filament is reduced by them to a motionless condition, 

 in which no farther contraction can be induced, and in which 

 the filament swells up in consequence of the imbibition of water. 



On the whole, the balance of evidence seems to me to be 

 strongly in favour of the view that the filaments of the teasel 

 consist of protoplasm in which a large proportion of resin is in 

 some way mingled. 



Probable functions of the filaments. — I shall now endeavour 

 to connect the above-described phenomena with known facts in 

 physiology, and to make a conjecture at what seems to be the 

 most probable function of the filaments. The class of facts 

 which appears to be most nearly related to the phenomena is 

 that of secretion. There can be little doubt that the protrusion 

 of filaments is closely related to the secretion of resin, for caps of 

 accumulated resin are found on the summits of the glands, while 

 inside the cells are spheres of the same substance. Ko one 

 would hesitate to consider these crusts as resin secreted by the 

 glands. But the filaments resemble these crusts in several ways, 

 €. g. in refusing to be stained by ordinary dyes, in being coloured 

 by alkanet and by iodine, and in being largely soluble in alcohol. 

 Moreover, incrustations of resin are only found on that variety 

 of gland from which filaments are protruded. The view is main- 

 tained by many physiologists that an act of secretion consists in 

 the disintegration or death of protoplasm. Every mass of what is 



