CHANGES IN NON-PREGNANT UTERUS 93 



-It is seen that oestrus, or the time of desire, begins normally 

 about the close of the period of destruction. With the ferret it 

 may be very prolonged, extending until the end of the recuperation 

 period, or even considerably beyond it. Consequently there may be 

 no metoestrum (strictly speaking) with the ferret, since the period 

 during which copulation can occur is liable to persist until the uterus 

 has reached the resting stage. 



(1) Period of Eesi.— The uterine mucosa in both the dog and the 



Fig. 13. — Section through prooestrous uterine mucosa of dog, showing 

 congested vessels between the glands. (From Marshall and Jolly.) 



ferret is bounded at the surface by an epithelium consisting of a 

 single row of columnar or cubical cells, and is continuous with that 

 of the glands and crypts. The latter are pits in the mucous mem- 

 brane. The stroma is a connective tissue, containing numerous 

 fusiform' cells. Blood-vessels of small size are fairly common. 

 Leucocytes do not appear to occur in the mucosa outside of the 

 vessels. Pigment is not present at this stage, at least ordinarily. 



(2) Period of Ormoth and Congestion. — The mucosa at this period 

 becomes slightly thickened, and tends to be mo^e compact. This is 

 .effected by cell divisions, but mitoses have not been observed. 

 Eetterer,^ who has contributed a short account of the changes in 



1 Eetterer, " Sur lea Modifications de la Muqueuse Uterine a I'Bpoque du 

 But," C. R. de la Sov. de Biol., vol. iv., 1892. 



