251 



development of the chicken lias heen until now bnt little 

 explored. The most important publications on this subject 

 have been silent up till the present time as to w^hat occurs in 

 the oviduct. I allude to the yelk-cleavage. The only (and 

 really very superficial) statements about it proceed from Coste, 

 and these ha\e not much reference to the formation of the 

 layers of the blastoderm. Without any knowledge of yelk- 

 cleavage, theories as to the elementary layers of the blas- 

 toderm are very vague, nor are the researches into the 

 pathology of the tissues which are connected with it less so. 

 It seemed advisable to me, therefore, to put the vvork in 

 question in this volume. 



The papers which follow this introductory essay by Pro- 

 fessor Strieker are as follows : 



1. Rkseakches on Inflammation of the Cornea. By 



William F. Nokris and S. Stricker. 

 The cornea of the frog is inflamed either by boring its 

 centre with a fine point of silver nitrate or by a needle and 

 threail. The structural elements are rendered apparent by 

 staining with gold chloride — five minutes in a half per cent, 

 solution — after which the cornea is placed for twenty-four 

 hours in very dilute acetic acid, and is mounted in glycerine. 

 It may also be studied without staining. The authors de- 

 monstrate the formation of the numerous oblong pus-cells of 

 the inflamed cornea, from the breaking up of the large stellate 

 cells of the normal cornea, and give tour admirably true 

 figures drawn by Dr. C Heitzmann, the artist of Strieker's 

 ' Handbuch,' in illustration. They also treat of the changes 

 of cells of the conjunctival and Descemetiau epithelium, and 

 of the active movements of the cells of the inflamed cornea. 



2. On Cell Division in Inflamed Tissues. By S. 



Stkicker. 

 In this ])aper Stricker describes his method of " draining," 

 by which he is able to keep tissues alive for some time under 

 the microscope, and so observe changes due to living pro- 

 cesses. Draining consists simply in passing in fresh blood- 

 serum at one side of the glass cover, and sucking it out at 

 the opposite side by means of a fine glass tube, so as to pro- 

 duce a circulation of nutritive oxygen-bearing fluid. It was 

 suggested to Stricker by Ludwig's and Schmidt's experiments 

 on the muscles. By this method Stricker has been able defi- 

 nitely to witness and to assert the division of cells. He has 

 seen the division in inflammation of corneal cells, and also of 

 certain cells in the tongue of the frog — a phenomenon which 



