152 DR. E. KLEIN AND PROFESSOR BURDON SANDERSON. 



the cover glass to and fro over it with a needle ; when this 

 is done, these " spindle-cells," whose long axis is parallel to 

 the side of the cover glass at which disturbance was applied, 

 turn round, show their flat sides and are then seen to be 

 plates, when the glass returns to its former position. They 

 again show their edges, appearing spindle-shaped and gra- 

 nular. Preparations from the same part also show very 

 beautifully the development of fiit, &c. 



b. Pathological conditions of the Omentum. 



In chronic inflammations the following alterations gene- 

 rally take place. The endothelium of the surface is in a 

 state of active proliferation, and especially at those spots 

 where we already observed proliferation in the normal state, 

 that is, at the stomata. The endothelium multiplies here as 

 it does in the centrum tendineum, so as to form buds and 

 cones raised above the surfoce. 



The plasmatic canal-cells undergo alterations of the same kind 

 as were described in the case of the centrum tendineum. One 

 phenomenon seen in certain parts of the parietal peritoneum 

 in young rabbits and guinea-pigs must be mentioned The 

 plasmatic cells which were swollen and also sometimes showed 

 division of the nucleus, shoAved also in their interior larger 

 or smaller molecules of fat and sometimes a vacuole. This 

 vacuole again contained, though it was not completely filled 

 by, a fat-globule, together with several young cells. The 

 envelope of protoplasm surrounding the vacuole was thin, 

 granular, nucleated, and connected by processes with the 

 neighbouring cells. Some of the young cells contained therein 

 were, doubtless, derived by division from the protoplasmic 

 envelope, but others were, in all probability, migratory cells 

 which had found their way in. 



In a certain stage of chronic inflammation produced by 

 the methods already enumerated, systems of nodes, cords, 

 and bridges, are found stretched over the surface of the 

 omentum and detached from it. 



These structures are wholly or in part covered with young 

 endothelium, and when they have reached a certain size are 

 provided with vessels, lymphatic sinuses, and a variable 

 number of migratory cells. 



The development of the above structures exhibits the 

 following stages : — 



{a) First of all, at places where there is a pseudo-stoma 

 the plasmatic cell constituting the pseudo-stoma puts out an 

 abruptly projecting homogeneous process ; the endothelium 



