EXPERIMENTAL METAPLASIA 365 



the ovarian tissue, that is to say, cysts Hned with ciliated epithe- 

 lium were produced in a small proportion of these experiments. 

 The implantation of pieces of ovary that have been heated to 30° C. 

 produces the same results as the implantation of unheated por- 

 tions. 



2. Cold. Small pieces of the ovary were frozen (at a tempera- 

 ture of -20° C), and allowed to thaw slowly. The thawing 

 process took about an hour, then after the lapse of 15 minutes the 

 ovary was again frozen. This process was repeated four times, 

 and then the pieces of ovary were implanted in the usual manner. 

 The animals were killed after 35 days, and sections showed that 

 a moderately intense inflammatory reaction had resulted; the 

 implanted tissue was invaded and nearly completely replaced by 

 blood cells, and was surrounded by a thick and compact la^^er of 

 fibroblasts. No ciliated epithelium was present, nor did the inner 

 layer of fibroblasts show any of the changes preliminary to its 

 production. 



3. Chemicals. Pieces of the ovary were treated for one hour 

 with various protoplasmic poisons, then well washed in sterile 

 sea water, and implanted. Solutions of the following substances 

 were tried: 



1 part corrosive sublimate in 2000 parts of sea water. 



2 per cent phenol in sea water. 



2 per cent of 30 per cent formalin in sea water. 



1 part of 20 vols, hydrogen peroxide to 10 parts of sea water. 



0.5 per cent of potassium cyanide in sea water. 



20 per cent alcohol in sea water. 



0.5 per cent of chloroform in sea water. 



In every case the animals died within ten days of the experiment, 

 showing signs of intense inflammation and often liquefaction of 

 the tissues at the site of the implantation. 



4. Degeneration in vitro. The ovary was thoroughly washed 

 in sterile sea water, cut in small pieces, and each piece placed in a 

 sterile test tube with a Uttle sterile sea water. Similar pieces 

 were placed in test tubes containing the blood of Pecten, collected 

 under aseptic conditions. The ovarian tissue was allowed to 

 degenerate in these tubes for three days, then cultures were made 



