STRUCTURE OF PROTOPLASM. 211 



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

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

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

 periment the arrest of the protoplasmic movement occurred in 

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

 off, the movements recommenced in thirty minutes. 



583. Kiihne experimented also upon the replacement of the 

 oxygen needful for protoplasmic movements by 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 anaesthetics, chloroform and ether, arrest 

 the movements of protoplasm. 2 



585. The structure of protoplasm. Having thus briefh" 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? 



By the highest power of the microscope it appears as a homo- 

 geneous hyaline mass holding in its substance, but apparently 

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

 plasmic matter is stained 1>3 T the skilful use of pigments, its 

 homogeneous character disappears. 



586. Schmitz has confirmed and extended the observations 

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

 toplasmic body 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, but 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 relatively 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 realit}- 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 very deeply with the dye; these 

 are the microsomata of Hanstein. 



1 Die Lehre von der Pflanzenzelle, p. 49. 



2 Claude Bernard : Lemons sur les Phenomeues tie la Vit>, 1879. 



