. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 650 UTERUS AND ITS APPENDAGES. condition. These, up to the time of impregna- tion, form the special and sole elements of the muscular tissue ; yet some physiologists even of the present day refuse to recognise in these a muscular character, although it is plain that the uterus so constructed has a contractile power. The occurrence of ab- ortion, sometimes at the very beginning of pregnancy, the expulsion of polypi and dys- menorrhceal membranes, and the painful con- tractions termed uterine colic, prove that the unimpreg
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 650 UTERUS AND ITS APPENDAGES. condition. These, up to the time of impregna- tion, form the special and sole elements of the muscular tissue ; yet some physiologists even of the present day refuse to recognise in these a muscular character, although it is plain that the uterus so constructed has a contractile power. The occurrence of ab- ortion, sometimes at the very beginning of pregnancy, the expulsion of polypi and dys- menorrhceal membranes, and the painful con- tractions termed uterine colic, prove that the unimpregnated uterus is so endowed. This non-recognition of a muscular character in the uterus before pregnancy has arisen from the minute size of the individual fibres, and from the difficulty of explaining why tliese should grow to a given point, and then cease to be developed. But F. M. Kilian has given a happy illustration of this point, de- rived from the observation of Kolliker, that the contractile fibre cells which are found in the coats of the smaller blood-vessels, pre- serve a relative proportionate size to those of the larger ones, wherein they are more fully developed. So also the contractile fibre cells of the uterus proceed to a certain point of development in the unimpregnated organ, and there stop. And in this respect it makes little or no difference whether the organ exa- mined has been taken from an infant or an adult. But when pregnancy takes place, the fibres proceed to a further stage of development. Their growth is now so considerable, that the contractile fibre cells, instead of a length of 0-002—0-003"', and width of Q'002"', in the fifth month, present a length of 0'06—Q-12'", and width of 0'0025—O'OOG'", or even O'Ol'", and in the second half of the sixth month, a length of 0-1—0-25'", a width of 0'004— 0-oby", and a thickness of 0'002—G'0028'"; consequently their length is increased from seven to eleven ti
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