Parturient Paresis in the Cow 929 



The theories regarding the nature of parturient paresis are in- 

 numerable, and difficult of classification. These may be divided 

 into four great classes, according to the belief veterinarians hold 

 as to the organ or system from which the disease takes its 

 origin. 



1. Many hold that the disease has its origin in some essential 

 change in the brain or spinal cord. They believe the disease to 

 consist of a congestion of the entire central nervous system, with 

 overfilling of the veins of the brain and spinal cord. Other veter- 

 inarians hold that the disease consists of anaemia and paralysis of 

 the central nervous system. 



2. Another group of veterinarians believes that the disease 

 has its essential origin in the uterus. In this group each indi- 

 vidual has an opinion of his own, which differs somewhat from 

 that of each of his colleagues. Some of them believe that, from 

 the uterine mucosa, there is absorbed into the system an amount 

 of infectious material or the products of bacterial activity within 

 the uterine cavity, which, acting upon the central nervous sys- 

 tem, produce the disease. The character of this toxic substance 

 has not been revealed, nor has any clear evidence been adduced 

 to show that such exists. It has not been shown why, if the 

 disease consists of the absorption of toxic substances from the 

 uterus, cows which are very thin in flesh, are poor milkers or 

 have suffered from dystokia should not just as readily suffer 

 from milk fever as deep milkers which are in high condition 

 and have calved easily. Others, like Stockfleth, hold that milk 

 fever is the result of embolism of the veins of the uterus, the 

 emboli escaping to other portions of the body. 



3. A third group of veterinarians, including Schmidt of Kol- 

 ding, holds that the disease arises from the mammary gland, and 

 consists of a toxaemia due to the absorption of colostrum, per- 

 haps incompletely formed, or other secretions which possess a 

 highly deleterious character. 



4. Harms holds that the disease is a form of aeraemia, or air 

 in the blood. In his post-mortem examinations he found air in 

 the veins of the brain, spinal cord, lungs and other organs. 

 This view has not been generally accepted. 



As already stated, post-mortem examination has virtually 

 failed to reveal anything definite regarding the actual cause or 

 character of the malady. This and that lesion has been re- 

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