366 MR T. ARTHUR HELME ON HISTOLOGICAL OBSERVATIONS ON 



2. Connective Tissue. 

 In the virgin uterus the muscle bundles lie closely together, scarcely separated by any 

 connective tissue, which is present only in very small amount, and is of the fully formed 

 white fibrous variety, with its different form of corpuscles, and with an admixture of elastic 

 fibres. When pregnancy occurs the connective tissue and vessels participate in the 

 general activity, so that there is along with the enlargement of the muscle cells a 

 corresponding and contemporary increase in the amount of connective tissue. But 

 during the first half of pregnancy this is moderate in amount, and the process goes on 

 to complete development, the cells becoming transformed into fully-developed fibrous 

 tissue, so that on examining a uterus at the 



14-th day of Pregnancy, one finds the connective tissne still small in amount, but round the 

 vessels there is young fibrous tissue forming, though there is no excess of cellular elements. 



16th day of Pregnancy. — The connective tissue has developed, especially in the zone between the 

 two muscle layers. Young vessels too are being formed by the connective tissue cells arranging 

 themselves in rows, chiefly at right angles to the circularly arranged layers of muscle cells. The 

 layers of muscle fibres, however, are not much broken in upon, the muscle bundles still lying closely 

 together. 



From this time the cellular character of the connective tissue begins to be more 



marked, there is a striking emigration of leucocytes from the vessels into the perivascular 



spaces; so that the cells increase largely in number, and do not go to complete formation 



of fibrous tissue. 



21st day of Pregnancy. — There has been great activity in the connective tissue. The small 

 vessels are surrounded by patches of connective tissue rich in cells, small leucocytes, and larger cells 

 with clear nuclei, and more protoplasm surrounding the nucleus. The connective tissue has also 

 developed among the muscle layers, so that the bundles lie apart, separated by strands of connective 

 tissue rich in cells. Many of these cells are transforming themselves into fibres, while others 

 retain their cellular character, the nucleus enlarging and becoming clearer. 



There is also a considerable emigration of leucocytes. At this time a very active 

 increase goes on in the connective tissue, especially between the two muscular coats 

 (longitudinal and circular) — the new tissue and vessels push their way in among the 

 muscle bundles, so that instead of the simple arrangement of one external longitudinal 

 and one internal circular coat, an intermediate layer, made up of bundles interlacing 

 in every direction, becomes developed. During the last three or four days there is an 

 entirely new phenomenon, a new variety of cell makes its appearance — colossal cells — 

 many of which are multinucleated. 



26th day of Pregnancy. — Great increase in connective tissue, with preponderance of cell 

 element. A change in the character of the cells is to be noled. In addition to the ordinary 

 connective tissue corpuscles and leucocytes, lying around the blood-vessels (among the connective 

 tissue), are larger cells with finely granular substance, and a single clear large nucleus, which 

 contains one or two very definite nucleoli. These epithelioid corpuscles, which are probably 

 ordinary wandering conneotive tissue cells enlarged, form islands round the vessels, and between the 

 muscle bundles. In other places new cells have appeared, large, granular, with two or three large 

 clear nuclei. 



27lh. day of Pregnancy. — Great increase of the large multinuclear cells. They are four or five 



