PROTOPLASM OF PLANT CELLS 123 



strands of protoplasm that traverse the cell sap in various 

 directions. In these strands the fibrillae always run parallel 

 to the direction of the long axis, i.e. to the direction in which 

 the strand is stretched. In favourable spots it is possible to 

 convince oneself even in the living object, that one is not 

 dealing with isolated fibrillse, but with fibrillse connected into 

 a mesh work. The structure is everywhere the same as 

 that which we met with in the stronger pseudopodial stems 

 of the Ehizopods. Of course, the observation is also 

 considerably hindered here by the continuous displacements 

 and alterations of the extended mesh work. 



In general I found the appearances more distinct in the 

 hairs of Malva and Urtica than in Tradescantia. Where 

 the streamings have temporarily slowed down, or especially 

 where portions of the protoplasmic strands have come to rest 

 for a time, one obtains especially favourable opportunities 

 for studying the meshwork, which alters its structural 

 character distinctly in the slight aggregations of protoplasm 

 arising from stoppage of the currents. It then passes from 

 the fibre-like meshwork into the ordinary reticulate mesh- 

 work, and vice versa portions with such a net-like meshwork 

 can be observed to pass over into the fibrous condition, when 

 they become drawn out into strands again. Fig. 9, Plate 

 IV. represents the marginal portion of a streaming proto- 

 plasmic strand of Malva, into which another strand opens 

 laterally ; in the latter the streaming has come to a stop at 

 the point of junction with the former. Hence this slightly 

 swollen spot appears distinctly composed of a reticulate 

 meshwork, while on the other hand the continuation of the 

 strand, as also the strand that is streaming, exhibit to per- 

 fection a structure of fibre-like meshes. In Malva, as 

 occasionally also in other objects, I further convinced 

 myself completely that the structure of the protoplasmic 

 strands, after killing with proper reagents, such as alcohol, 

 picro-sulphuric acid, etc., undergoes no alteration, apart from 

 the fact that it becomes sharper and more distinct. Oppor- 

 tunity is frequently offered of making observations on 

 threads of protoplasm drawn out to extreme fineness, in 

 which nothing is to be observed in the way of structure. On 



