EXPERIMENTAL METAPLASIA 359 



through the semi-transparent muscle. A small cube of the muscle 

 containing the ovarian tissue in the middle was cut out and placed 

 for about three hours in Zenker's fluid, well washed, treated with 

 dilute iodine, and finally embedded in paraffin. Serial sections 

 were then cut, and stained in very dilute Delafield's ha^matoxy- 

 lin. Other stains and fixatives were used for especial purposes, 

 but the above procedure was found to be the most satisfactory 

 as a routine method. 



It is noteworthy that even after the ovarian tissue has been im- 

 planted into the muscle for as long as four months, the orange 

 color is not lost or even diminished in intensity, so that the site 

 of the implantation can always easily be distinguished. 



RESULTS OF THE IMPLANTATION OF PIECES OF THE MATURE 

 OVARY INTO THE ADDUCTOR MUSCLE, AND THE SUBSEQUENT 

 DEVELOPMENT OF CILIATED EPITHELIUM FROM THE FIBRO 

 BLASTS FORMED AROUND IT 



The sequence of events after the implantation of pieces of the 

 ripe gonad of one specimen of Pecten maximus into the adductor 

 muscle of other animals of the same species is identical with that 

 occurring when the same experiments are performed on Pecten 

 opercularis. 



Pieces of the ripe ovary after ejection from the transplanting 

 needle into the muscle, are roughly spherical in shape, and measure 

 from 1 mm. to 0.5 mm. in diameter according to the size of the 

 needle used. Very soon after implantation such a piece of ova- 

 rian tissue becomes surrounded by a thin layer of agglutinated 

 blood corpuscles, and the track of the needle is closed by a similar 

 mass of blood corpuscles forming a plasmodial mass, which, by its 

 contraction, draws together the tissues that have been displaced 

 by the passage of the needle (Drew, '10). This condition can be 

 seen in sections from animals that have been killed about one hour 

 after the implantation has been made. If the operation has been 

 conducted aseptically, the resulting inflammatory reaction is very 

 slight. There appears to be a definite determination of the blood 

 cells towards the ovarian tissue, but there is nothing approaching 



