PROTOPLASMIC MOVEMENT. 383 



movement. The threads themselves often at times show no 

 movement, and at other times only slow changes of form which 

 consist in lengthenings and shortenings, in the formation of 

 nodules, also of curved or irregular bends and branchings. 

 They may be quite withdrawn into the protoplasmic mass. 

 When they touch each other they fuse together, very easily 

 forming sheets. 



The characteristic phenomenon of the movements of granules 

 is described by Max Schultze ^ in the following way : — ''It is a 

 gliding, a flowing of the embedded granules in the substance of 

 the threads. With greater or less rapidity these granules 

 move in the threads either towards the periphery or in the 

 opposite direction, and often, even in the thinnest fibres, in both 

 directions at once. They may either simply pass one another 

 or may move round one another, and after a short pause move 

 on in the original direction, or the one granule may carry the 

 other along with it. Like pedestrians in a broad street, the 

 granules may swarm together in a broad fibre, many of them 

 stopping from time to time and shaking or trembling merely, 

 always, however, following a direction corresponding with the 

 long axis of the threads. Often they stand still in the midst 

 of their course and reverse their direction, the most (? Engel- 

 mann), however, succeed in reaching the extremity of their 

 threads and here first change their direction. 



" All the granules in a thread do not move with the same 

 rapidity, so that one often overtakes another, the more rapidly 

 moving granules pushing the others on, or, the latter stopping 

 the former in their course. Where threads join one another, 

 granules often pass over from one into the other, and at such 

 places there are often broad expanses which have been formed 

 out of agglomerations of thread substance out of which then, as 

 independent processes, further threads are formed, or into 

 which, already existing ones are, as it were, absorbed. Many 

 granules quite evidently run in the most superficial layers of 

 the threads from which they may be seen projecting. Possibly 

 they all have a superficial position. Besides the small granules 

 1 Max Schultze, 'Das Protoplasma,' &c., p. 11. 



VOL. XXIV. NEW SER, D D 



