THE MUSCULAR FIBRE AND CONNECTIVE TISSUE OF THE UTERUS. 365 



These observers excised small bits of the muscular coat of the Triton's stomach, and after 

 allowing the process of healing to go on for various periods (a few weeks to six months), 

 examined the site of injury. They found at the edges of the cut muscular layers 

 numbers of muscle cells, whose nuclei presented the characteristic karyokinetic figures, 

 showing that the renovation of non-striped muscle takes place by the development of 

 new cells from parent muscle cells. We may then dismiss from our minds the possibility 

 of any development of muscle fibres from leucocytes or embryonal elements, &c, and 

 take as proof of the occurrence or non-occurrence of the development of new muscle 

 fibres the presence or absence of dividing nuclei of the existing cells. Accordingly, 

 preparations of the uterus at all stages of pregnancy were made with this single object 

 in view — to examine the nuclei for division. The method I employed was that employed 

 by Stilling and Pfitzner, and also the picric acid method. That the methods were 

 not faulty is shown by the numbers of karyokinetic figures observed in the somewhat 

 large nuclei of the clear glandular epithelial cells ; but in the muscular tissue not a 

 single dividing nucleus was seen at any stage of pregnancy. The cells presented a 

 gradually advancing growth in all diameters, in the nucleus as well as in the cell-body. 

 It is also noteworthy, that as the cells increase in size they begin to present longitudinal 

 striations and transverse rings — the former so marked towards the end of pregnancy 

 that the transverse sections of the muscle cells may be easily mistaken for the prickle 

 cells of the skin. During the last few days a very rapid increase in the size of the 

 individual cells, and a marked change in their appearance, are to be noticed. The cells 

 increase rapidly in volume, and assume a clearer, glassy aspect, looking as if the pro- 

 toplasm were saturated and distended with water. At the same time, some of the cells 

 present the appearance of " vacuoles," clearer spaces with a definite outline, generally 

 by the side of the nucleus ; the latter being pushed outwards and curved, as it were, by 

 this vacuole, so that it, the nucleus, seems to form part of the periphery of the vacuole. 

 The appearances remind one of those of cells which have undergone what pathologists 

 describe as serous degeneration — their refractile character also suggesting an early stage 

 of hyaline degeneration.* 



The importance of these changes I shall speak of shortly, but with regard to the 

 question at present before us, my observations show that the increase of the uterine 

 musculature during pregnancy is brought about, not by a double process, but only by the 

 increase in volume of the existing muscle cells. 



One uterus which T examined at the 21st day of pregnancy had only one horn 

 impregnated — the unimpregnated horn, however, had undergone a similar hypertrophy 

 in all its parts. 



* I find that this appearance has heen noted by Dr Julius Elischer, who, in a paper on " The Finer Anatomy 

 of the Muscle-fibre of the Uterus" (Arch. f. Gynec. Band ix., 1876, s. 15), says — "My observations of the contractile 

 substance show a decided difference according as the muscle of a non-pregnant, or, on the other hand, of a pregnant 

 uterus is taken. Without further treatment with reagents, only teased in amniotic fluid, the muscle fibres of the non- 

 pregnant uterus show the contractile substance more markedly striated, ami have an appearance (Glanz) much darker 

 than those of the pregnant organ, whose appearance, I might say, reminds one of that of slight amyloid degeneration." 



