One can not be certain, therefore, from the absence of cedema, of the absence of albuminuria; and the necessity of examining the urine of all pregnant women cannot be too much insisted on.
There remains, then, the last theory: 5th. Eclampsia depends upon a poisoning of the Blood, which renders this Fluid unfit to stimulate regularly the Nervous Centres.—What is the toxic principle ? Is it urea ? Is it the transformation of this urea into car bonate of ammonia ? Is it the extractive or coloring materials of the blood ? Each of these theories have been sustained, and thence the three theories of unemia, of ammomemia, and urimemia.
1. Urcemia—.Although Rostock, Christison and Gregory, first described the presence of an excess of urea in the blood of eclamptic patients, it was Wilson who, in 1833, created the word, and the morbid entity, ura3mia. (Hypolitte.) Adopted since by all authors, this word has re mained in science, but if the word has remained, tt is not so with the theory, which attributes the cerebral phenomena to the presence of an excess of urea in the blood. While Wilson, Hammond, Treitz, Lalesky, consider urea as poisonous, Babington, Bright, O. Rees, Christison, Fre richs, Schattin, Segalas, Hoppe, Gallois, Brown-S6quard, Cl. Bernard, Oppolzer, prove that urea is inoffensive, and the theory of Wilson was overthrown by the experiments of Cl. Bernard, who, injecting urea into the veins without producing convulsions, proved that urea is incapable of producing the nervous complimtions of albuminuria and eclampsia. The fact, itself, of the excess of urea in the blood during the eclamptic attacks, has been confirmed by the analyses of Devilliers and Regnault, Wurtz and Berthelot, Gubler, Ritter, Parkers, Schtittin, Mosier, etc. Moreover, recent researches in regard to the temperature in eclampsia, en tirely overthrows the theory of ura3mia, because the temperature in ursemia is lowered gradually and considerably, while in eclampsia, on the contrary, it continues to rise. Let us add, finally, that in cholera, when an enormous quantity of urea is found in the blood, eclamptic convulsions are not observed.
2. Ammoncemia.—Impressed by the impossibility of explaining these complications by uremia, Frerichs proposed the following theory: It is not urea by itself which leads to these complications, but they are due to the fact that urea, accumulating in the blood, is transformed, by a fer ment, into carbonate of ammonia. It is to this carbonate of ammonia
that the nervous complications are due. According to Mercier, it is not carbonate of ammonia, but urate of ammonia, which is the toxic agent. Finally, Treitz returned to the theory of carbonate of ammonia, but it is no longer, according to him, in the blood that the change of urea into carbonate of ammonia is made. " Whenever the urinary secretion is sup pressed, the excretory matter, especially urea, accumulates in the blood. Now this urea passes from the blood into all the secretions of the econ omy, but it is, above all, the intestinal mucous membrane which eliminates the gre,atest quantity of urea. Poured into the digestive tube, the urea is changed into carbonate of ammonia, and produces many lesions. At this time the ammoniacal salt has been reabsorbed, and it passes into the blood, and the more surely 118 the important function of the intestinal mucous membrane is exactly the absorption of the liquids which bathe it. It is the reabsorption of this ammonia contained in the intestine which produces ammoniacal intoxication or ammontemia. This theory, upheld by Christison, Jaksh, Brettet Bird, Oppolzer, Wieger, &atm, has been attacked by Richardson, Picard, La,lesky, and overthrown finally by Cl. Bernard, who has shown " that the blood of a well or sick person contains almost always carbonate of ammonia; and that, if urea is found in the in testinal fluid as an ammonia salt, and not as urea, it is only because when this substance appears in the intestinal canal, it dissolves in the fluids, in the midst of which fermentation goes on, which continually destroys the ammonia,cal salts, as soon as they are found." 3d. has declared that the kidneys secrete not only urea, but other substances still little known, (creatin, creatinin, leucine, etc.), and designated under the vague name of extractive materials; these accompany urea, remain in the blood, and produce blood poisoning, and consequently convulsions. This theory, upheld by Reuling, Hoppe, Op pier, Perls, Laleaky, Fabius, Fournier, Chalvet and Gubler, has received from the latter authors the name of urinannia, by which it is known to day. The experiments of ChitHan, 1865, have confirmed it, and it is ac cepted by Peter.