THE MUSCULAR FIBRE AND CONNECTIVE TUSSUE OF THE UTERUS. 367 



times the size of the large epithelioid connective tissue cells, but their size varies considerably ; the 

 shape also varies, but they are generally spheroidal, with an even or irregular outline. The cell 

 substance is very granular, but the nuclei, which vary from one to three or four in number, are 

 particularly clear, and possess two or three very definite nucleoli. These huge cells are found 

 chiefly in groups in the strands of connective tissue separating the muscle bundles; some of the 

 cells, however, lie almost isolated, and others again seem to have wandered in among the smaller 

 muscle bundles. Where these cells are in greatest number, there is a corresponding diminution 

 in the number of the smaller single nucleated cells, giving the impression that these plasmodia 

 are formed by growth, and then fusion of the above single nucleated cells. 



Being developed then in these large numbers at this special period, these plasmodia 

 must have some definite object, and it is natural to conclude that it must be in prepara- 

 tion for the puerperal changes. As to their origin, it is probable they arise from the 

 smaller cells with single large clear nuclei, which again have had their origin in the 

 emigrated leucocytes. 



3. Vessels. 



With regard to the development of new vessels, it is impossible to make out com- 

 pletely all the processes. But that they increase by multiplication of the existing endo- 

 thelial cells is demonstrated in several of my specimens (fig. 1), this multiplication 

 being originated by the usual nuclear movements— not a process of budding with subsequent 

 subdivision of the nucleus. It is an interstitial increase. But these dividing cells are not 

 sufficiently numerous to account for the great increase of capillary vessels, and several 

 preparations show appearances that suggest the new vessels are largely formed by the 

 arrangement and junction of the endothelioid cells of the connective tissues. An active 

 process of growth goes on in arteries, veins, and capillaries. 



An interesting fact is the sinus-like character of the veins which in many cases 

 appear as periarterial sinuses (fig. 4), large spaces lying alongside of and sometimes almost 

 encircling the arterial tube, and having merely a thin wall made up of endothelial cells 

 and devoid of muscular tissue. 



An important point is the fact that during the last two or three days of pregnancy, 

 the lining cells of the vessels and the muscle cells of the arteries undergo a rapid swelling, 

 becoming clear and hyaline. This is of a most pronounced character, and is important, as 

 it must tend to diminish the amount of blood supply to the contractile and connective 

 tissue elements of the uterus. 



Looking then at the uterus as a whole, we find a gradual increase in its volume, due to 

 the growth of all its constituent elements : the connective tissue, vessels and glands by 

 an increase in their amount, i.e., a development of new elements or new formation : the 

 muscular tissue by a process of simple hypertrophy of pre-existing cells. Towards the 

 last days of pregnancy, we find evidences of even greater activity of a remarkable three- 

 fold character : — 



1. The swelling of the muscle cells till they become distended and hyaline. 



2. The swelling of the lining endothelium and of the muscle cells of the vessels. 



3. The appearance of numerous plasmodia. 



VOL. XXXV. PART 8. 3 P 



