674 



UTERUS AND ITS APPENDAGES. 



upon the mode of its innervation or excite- 

 ment. So that if in a situation where organic 

 fibre is usually found, the intestine, for ex- 

 ample, of cyprinus, the part is composed of 

 striated muscle, then no organic or peristaltic 

 action can be produced in it ; but upon excite- 

 ment, contractions of the kind usually seen in 

 striated muscular fibre ensue.* 



In the same way the peristaltic action of the 

 uterus, although exhibiting certain differences, 

 according to the manner in which it is evoked, 

 is nevertheless to be referred to the peculiar 

 composition of unstriated fibre, and not to 

 the mode of innervation or excitement of the 

 organ. 



For the muscular fibre of the uterus is not 

 bound up in separate sheaths, as voluntary 

 muscles are, nor do the fibres run principally 

 in one direction, nor are they long and con- 

 tinuous conditions all favourable to that 

 quick transmission of nerve influence, and 

 rapid action which occur in voluntary muscle 

 but the fibre cells are for the most part 

 distinct, lying in apposition, or imbedded in a 

 matrix of amorphous tissue (jig. 436.), and 

 forming by their combination intricate laminae. 

 Through a tissue so composed, the in- 

 fluence of a stimulus can only be propagated 

 slowly, and the organ formed of it can only 

 contract after a vermicular or peristaltic man- 

 ner. Nevertheless, the power, the endurance, 

 and the orderliness of the action that ensues, 

 will be, to a certain extent, dependent upon 

 the nature and mode of application of the 

 excitant. It cannot be questioned that, under 

 many circumstances, the direct application of 

 a stimulus to the uterine muscular structure 

 excites its contractions in the same manner 

 that the food does those of the oesophagus 

 and intestines, without any intervention what- 

 ever of nerve. This happens when the hand 

 is passed into the bare uterine cavity after 

 labour, or when the membranes are separated 

 from the inner surface of the uterus by a 

 catheter. 



To bring such an organ into co-ordinated 

 action, all that appears necessary is, that 

 nerve fibres should enter its tissue at a certain 

 number of distinct points or centres, whence 

 the irritation excited at these spots being 

 propagated from fibre to fibre, may spread 

 through the mass, until the whole is brought 

 into harmonious operation. 



And it need not excite surprise if these 

 centres of excitement are few, and the nerves 

 of the gravid uterus consequently not nume- 

 rous ; for a more abundant supply of nerve 

 force, and more rapidly recurring contrac- 

 tions, would be prejudicial in labour, by bring- 

 ing the uterine walls more constantly and 

 violently into contact with the foetus, and by 

 driving out the blood passing through them 

 so rapidly as to cause dangerous regurgita- 

 tion, or so frequently as to produce foetal 

 asphyxia, through too constant interruption 

 of the placental circulation. 



* Weber, in the article Muskelbewegung, in 

 Wagner's Handworterbuch. 1856. 



It is in favour of the views of Wigand, who 

 maintains that uterine action begins at the 

 cervix, and travels upwards, that the cervix 

 receives a larger supply of nerves than the 

 fundus, so that the action may be here first 

 established, and the fundus afterwards ex- 

 cited. But however this may be, it is known 

 that unless all parts of the organ are eventu- 

 ally brought into consent, the labour does not 

 proceed regularly, for if one portion is felt to 

 be hard, and another at the same time soft, 

 irregular action and spurious pains ensue. 

 To ensure, therefore, consentaneous action 

 between- the respective points of the uterine 

 fibre at which the nerves enter its tissue, and 

 to establish and regulate the movements, ap- 

 pear to be the offices of the nerves in relation 

 to the uterine structure. 



Of the rythmic action of the uterus, and its 

 cause. The uterus, like the heart and the 

 respiratory muscles, is time-regulated or 

 rythmic in its action. In this action the 

 usual three rythmic periods are noticeable, 

 viz., a period of contraction, a period of re- 

 laxation, and one of repose. 



The sensible phenomena which accompany 

 the first period are, a gradually increasing and 

 sustained hardness of the uterus, a gradual 

 approach and continuance of suffering, and, 

 after a time, a certain advance of the pre- 

 senting part of the child. These occur- 

 rences do not commence coincidently, but 

 each overtakes the other in the order enu- 

 merated. 



The phenomena of the second period are, 

 the gradual subsidence of the hardness, the 

 gradual passing away of the pain, and the re- 

 tiring of the presenting part, and these are 

 more nearly coincident than the former. 



The third period is marked by an absence 

 of all sensible signs. 



These three periods together constitute the 

 uterine rythm, which observes certain laws, 

 that are in some respects different from those 

 which govern the rythmic action of other 

 parts, as for example, of the circulatory and 

 respiratory organs respectively. 



In the action of the uterus, 'the repeats take 

 place more slowly than in either of the in- 

 stances just named, although between these 

 two, also, there is a proportionate difference, 

 nearly, or quite as great. The heart's rhythm 

 being quickest, the respiratory rythm slower, 

 and that of the uterus slowest of all. 



But the rythm of the uterus does not ob- 

 serve a constant or uniform rate. At the 

 commencement of labour, the order of se- 

 quence of the rythmic motion remains for a 

 time tolerably constant ; but as the process 

 advances the rythm becomes modified, so 

 that, like the example of the heart under 

 violent emotion, the interval shortens, 

 while the force and vigour of the contractions 

 increase. 



It is a matter of great interest to discover, 

 if possible, the determining cause of this 

 rythm ; that which constitutes the regulating 

 as well as the disturbing force. The latter 

 should be rather termed the accelerating 



