Etiology. 781 



hours after ll'A of the total estimated weif^ht of the blood of the body was taken 

 away from t)ie jugular vein in a space of time of from 20 to 70 minutes, without 

 any disturbances being exhibited, except a nio<lerately quickened pulse and pale color 

 of the mucous membrane. The same was noticed in a heifer where 32% of the 

 total quantity of blood was taken away. It was further noticed in two mares ex- 

 ])erimented on, where 42% to 44% of the whole quantity of blood was removed, that 

 the only symptoms exhibited were quivering of the muscles and an anxious look. 

 On the other hand Stahn in a case of fatal hemorrahge into the womb, without rup- 

 ture, in a cow di<l not witness parturient paresis, the clinical picture of paresis 

 ])uerperalis was only observed in such cows (Oebauer, Meier, Eeinhardt, Habicht) 

 where in consequence of uterine or vaginal rupture, not only blood but other matter 

 passed into the abdominal cavity. 



Tt is to be noted, moreover, that as long as the vasomotor apparatus is uninjured 

 it always makes provision that the brain receive the needed amount of blood, not 

 only in case of an increased flow of blood to other organs (with the exception of the 

 very large total area of the abdominal vessels which are snpplied by the splanchnic 

 nerve), but also in case of a vasoconstriction in these organs. On the other hand 

 experiments on dead animals can give no indication as to the total amount of blood in 

 the udder of living animals. Watery solutions easily diffuse through the dead vessel 

 walls into the adjoining udder tissue, while an injection of gypsum into the blood 

 vessels, especially into the veins, causes an abnormally severe dilation of the vessels, 

 since these exert an insuperable resistance in their fine branches. It appears, more- 

 over, very strange that about half the amount of the total blood of the body 

 should be present in the udder after parturition. 



Tt would have to be ascertained whether or not in sudden changes the food 

 contents of the abdominal cavity shortly after parturition a lowering of blood pressure 

 occurs in such a manner that a decided diminution of the internal abdominal pres- 

 sure causes a great determination of blood into the very wide vascular area of the 

 abdominal organs for M'hich even an uninjured vaso-motor apparatus cannot immedi- 

 ately procure efficient compensation. 



Secondly, an infection is accepted as the cause of the disease. 

 Supported by a certain similarity between parturient paresis and 

 ptomaine poisoning, Ziindel, Stockfleth and later also Schmidt-Miilheim 

 assumed a toxic action, the toxins being due to a slowly progressing putre- 

 faction of the lochia. This hypothesis was more or less related to that 

 held by Eloire, Chauveau, Bissauge and Schneidemiihl. — Nocard sought 

 the cause of the disease in an infection proceeding from the womb with 

 a resulting intoxication of the central nervous system, especially of the 

 medulla oblongata, by toxins of staphylococci which increased in the 

 uterus after parturition. In like manner Guillebeau & Hess assume an 

 infection by streptococci and staphylococci through the genital tract 

 injured during parturition; this would be similar to puerperal septi- 

 cemia, but with this difference, that in milk fever only an absorption of 

 the bacterial poisons occur, which then result in paralysis of the 

 vaso-motor centers, and through this a tense filling of the blood vessels 

 of the abdomen, of the uterus, and especially of the udder itself. — The 

 favorable result obtained by Kniisel with oxygen inflations of the 

 udder led him to believe that there was an infection and intoxication 

 proceeding from the udder and caused by anaerobic bacteria. 



Against all these hypotheses many objections can be raised. First of all it 

 has not yet been possible to demonstrate the supposed poison, putrefying lochia or 

 the supposed pathogenic bacteria. (Streptococci, staphylococci and other bacteria can 

 easily gain access to the uterus after parturition without necessarily producing at 

 the same time a pathogenic effect.) Finally between parturition paresis and ptomaine 

 poisoning (botulismus, allantiasis) there is an essential difference, for in milk fever 

 the loss of consciousness is the principal symptom of the disease, whilst in ptomaine 

 poisoning without particularly marked disturbances of consciousness paralysis is a 



