42 Veterinary Medicine. 



grayish color and a loss of its normal translucency. The cells of 

 the affected organs are seen under the microscope to be filled with 

 small albuminous granules which may be so abundant as to com- 

 pletely conceal the cell structure. The granules are insoluble in 

 ether, but disappear under acetic acid. This condition of the 

 cells is often associated with the exudative forms of inflammation. 



Cell Proliferation and Change. In the nonvascular organ 

 attacked by inflammation the multiplication of tissue cells and 

 their resumption of amoeboid movements is a constant phenome- 

 non. Virchow insisted on the fundamental relation of the cell to 

 the morbid process, and Goodsir and Redfern showed the rapid 

 increase of the cells of articular cartilage in attacks of arthritis. 

 There is first a sensible increase of the nucleus of the cartilage 

 cell which shows a more extended and deeper staining in carmine 

 or aniline ; then by a special method of division (karyokinesis) 

 the cell and nucleus divide in two ; by a similar process these 

 divide in four and so on in regular order. Meanwhile the carti- 

 laginous substance becomes softened and finally dissolves and dis- 

 appears, leaving in the place a mass of closely aggregated cells. 



In the nonvascular transparent cornea, the membrane of Des- 

 cemet, the epithelium of serous membranes and in the epidermis 

 a similar cell multiplication occurs, also in the lateral cartilages of 

 the horse's foot. 



To follow the indirect cell division by karyokinesis, we must 

 note the cell as a semi-solid mass, formed of protoplasm and 

 nucleus, each having as its framework a network of exceedingly 

 fine inter-crossing filaments, much finer in the nucleus than in 

 the cell protoplasm. The nuclear filaments stain with haematoxy- 

 lon and safranin and are called chromatin threads. The inter- 

 vening non-staining material is achromatine . The nucleus has a 

 membraneous envelope in two layers, of which the inner only 

 stains. When about to divide two poles are formed in the cell 

 protoplasm opposite to each other and near the nucleus the fila- 

 ments concentrating to the poles. The chromatin threads in the 

 nucleus thicken, become convoluted, split and multiply, and draw 

 into their substance the chromatin layer of the envelope. Next 

 the chromatin threads form long loops directed toward an achro- 

 matine centre or pole like a star, and this is followed by the pro- 

 gressive division of the star-shaped mass into two equal parts. 



