STRUCTURE OP PROTOPLASM. 211 



cells in which the movements were plainlj- seen, in olive-oil, in 

 order to exclude the air. A short time after this was done the 

 movement stopped. In Hofmeister's ^ repetition of Corti's ex- 

 periment the arrest of the protoplasmic movement occurred in 

 five minntes in olive-oil ; after the oil had been carefully- poured 

 off, the movements recommenced in thirt}- minutes. 



583. Kiihne experimented also upon the replacement of the 

 ox3-gen needful for protoplasmic movements bj- carbonic acid, 

 and found this gas much better than oil for excluding air. 

 Upon removal of the plant-hairs from oil, it is difficult to take 

 away the last trace of adherent oil. 



584. The ordinary auiesthetics, chloroform and ether, arrest 

 the movements of protoplasm.^ 



585. The strnctnre of protoplasm. Having thus briefl\- ex- 

 amined some of the more striking phenomena of protoplasmic 

 movement, the question must now be asked. What is the struc- 

 ture of a substance which exhibits these phenomena? 



B^^ the highest power of the microscope it appears as a homo- 

 geneous lyaline mass holding in its substance, but apparently 

 as foreign bodies, ver}- minute granules. But when the proto- 

 plasmic matter is stained bj- the skilful use of pigments, its 

 homogeneous cliaracter disappears. 



586. Schmitz has confirmed and extended the observations 

 of Frommann, which show that in some cases at least the pro- 

 toplasmic bodj' is a reticulated framework of extremely delicate 

 fibrils, between the meshes of which is a homogeneous liquid. 

 There is unobstructed communication between the different 

 meshes, so that the whole of the liquid may be regarded as 

 practically one mass. The network of fibrils does not possess 

 any rigidity, bat is constantly mobile under favorable condi- 

 tions, and undergoes manifold changes of form. The reticulated 

 structure is most clearly- seen in the parietal protoplasm, and the 

 larger bands of cells which contain relativel3' considerable sap. 



When, after hardening, protoplasm is carefully stained with 

 haematoxylin, the whole mass appears to be equally and evenly 

 colored ; but it is in reality- only the network which takes up the 

 color, the liquid in the meshes remaining uncolored. 



Imbedded in the protoplasm, especially in the inner portions, 

 there are generally minute granules which have a high degree 

 of refringency, and which stain ver^- deeply with the dye ; these 

 are the microsomata of Hanstein. 



1 Die Lehre von der Pflanzenzelle, p. 49. 



2 Claude Bernard : LcQons sur les Phenomeiies de la Vie, 1879. 



