It has been shown, he says, that the sensory nerves, extending int,o the walls of the uterus, may at once, by irritation excited in them during pregnancy and labor, produce a reflex action on the motor nerves which are given off from the spine. Admit this, tad it is no longer doubted that this reflex action, under the influence of extreme congestion, (renal hyperzemia), which may increase the excitability of the general nervous system, may go beyond its normal limits and produce contractions, con vulsions, of the muscles supplied by these nerves. If the excitation pro duced in the sensory nerves of the 'uterus is not extreme, or even limited to a small part of the sensory nerves, these reflex movements will be pro duced in the voluntary muscles only to a very limited extent. This is con firmed every day by cramps that are observed in the lower extremities, where terminal spinal nerves are distributed. If the irritation increases and extends, reflex convulsions muy be seen in the muscles of the trunk. This increase of sensory uterine irritation during labor may be produced by all the causes which may make traction on or compress the nervous filaments during the uterine contractions. Thus we see these convulsions occur in parturient women, in cases of mechanical obstruction to labor, which exerts on the uterus a greater force than customary; when the uterine wall is in close apposition to the child, and makes considerable pressure.
It is the same when it is an isolated part of the organ which is exposed to those causes of excitement, (inferior segment of uterus in the vicinity of the os internum.) All the causes which lessen dilatation may also provoke convulsions, partly because the inferior segment of the uterus is compressed in a marked degree by the uterine contents, and, partly, because the longitudinal fibres which produce the dilatation are exposed to in creased tractions. This is one of the reasons which explain the greater frequency of eclampsia in primiparge. Finally, as a cause favoring con vulsions, we must mention spasmodic contractions of the os ext,ernum, and all those causes which produce rigidity. Moreover, extraneous causes, foreign to the mother, may produce this excessive irritability of the uter ine nerves, and lead to convulsions by reflex action, i.e., manual or in strumental dilatations of the cervix. The central nervous irritation may react either on the spine or brain.
As for the spine, we must consider hypertemia of the cord and its mem branes. A priori, it may be admitted, that the same causes which, dur ing pregnancy and confinement, lead to congestion of the abdominal viscera, and particularly the kidneys, may produce congestion of the lower segment of the cord; and experience has shown that pregnancy is accom panied almost always by congestion in the lower part of the cord. But
no doubt, hyperaemia in this part of the cord does not favor convulsions. We must admit that a woman, during pregnancy, confinement and the puerperal state, is predisposed more than in all other conditions to these convulsions. It is, however, understood that these congestions, to cause these convulsions, must not exceed a certain degree, and must not be ac companied by exudations into the medullary tissue or the arachnoid sae, for otherwise we would not have convulsions, but paralysis. Finally, no one doubts but that the medullary irritation causing convulsions must have its origin in the brain.
Eclampsia then may, according to Scanzoni, show itself in three forms: 1st. Reflex convulsions arising from the peripheral extremity of the uter inc sensory nerves; 2d. Spinal convulsions arising from the direct irrita tion of the spinal cord, an irritation which is referred to the peripheral extremities; 3d. Cerebral convulsions, when the irritation arises in the brain, and is referred to the spinal cord.
Cazeaux says that this last form may be controverted, and, according to him, spinal irritation is always the origin of eclampsia. " It is a fact established by all physiologists, that the irritation of the cord, medulla, or tubercula quadrigemina, alone causes convulsions, while irritation of other points of the cerebrum or cerebellum produce nothing similar. Cerebral lesions may indeed destroy voluntary movements, but the involuntary con tractions, those of which the excess and irregularity constitute eclampsia, are not affected. These last may still be produced by spinal irritation or of its nerves when the brain and cerebellum have been destroyed." In 1875 Cohen of IIamburg proposed two original ideas, of which we will speak in a few words. According to him there are two kinds of eclampsia: " Uterine eclampsia, which may be produced by irritation of the uterus, referred secondarily to the brain; cerebral eclampsia, which, on the contrary, originates in the brain, and is referred secondarily to the uterus, thus causing convulsions. These two forms are found clinically. Uterine eclampsia is divided into two classes, one which is called uterine eclampsia at term, which results in phenomena which occur during labor and confinement; the other eclampsia before term, which depends upon the contact. at the end of the sixth month, between the fmtus and the inferior segment of the uterus, and on the distension and change of form which the lower uterine segment undergoes. This form will give a favorable prognosis for mother and child; the other, cerebral eclampsia, depends upon a cerebral affection, and presents some of these signs from the outset.