868 Malt and Potato Eruption. 



that the potato distilleries are generally in full operation only 

 during the winter and the animals are generally fed only with 

 distiller's slop at this time. Yet it appears not unlikely that 

 the frequent occurrence of the affection in spring is related to 

 the sprouting of the potatoes at that time or with their decompo- 

 sition, or with the strong fermentation of the slop. Musterle 

 has noticed that fermentation and acidification become very ac- 

 tive if slop mixed with raw fodder is allowed to stand several 

 hours before feeding. That this cannot be the only cause, how- 

 ever, is proved by the fact that even fresh tubers and the leaves 

 or stalks of the potato plant can occasion the disease and even 

 produce it in horses, if they are used as litter and come in con- 

 tact with the skin of the fetlock region (Roll). This circum- 

 stance and the fact that malt eczema occurs only in certain years 

 seem to prove that potatoes cause the disease only under cer- 

 tain conditions that are not yet clearly imderstood. 



Concerning the immediate cause there seems to be a connection between the 

 occurrence of the disease, tlie amount of slop or potatoes ingested and the presence 

 of a chemical poison in the potatoes (Johne). The poison is absorbed from the 

 digestive canal and gains entrance to the blood vessels of the skin, producing a 

 similar effect on the papillary bodies and their epi<lermal layer to that of many 

 mineral poisons (mercury, bromine). This view is supported by the relative 

 immunity of milk cows, since these eliminate a great part of the poison through 

 the milk, and if such milk is taken by sucking calves or foals a violent intestinal 

 catarrh or a malt rash is caused in them. The preferable or even almost exclusive 

 localization of the disease in the feet may be due to a mechanical irritation of 

 these parts of the body and to the fact that they are most exposed to the action 

 of liquid feces and soaked litter. 



Solanin has been looked upon as the immediate cause of the disease, since 

 this alkaloid is formed in great quantity in sprouting potatoes. But, apart from 

 the absence of the characteristic nervous symptoms of solanin poisoning ((lepression, 

 reeling, paralysis, retarded breathing) , the correctness of this assumption is contra- 

 ilicted by the fact that the disease occurs also afteB feeding on solanin-free, sprout- 

 ing potatoes as w:ell as on the leafy portions of the plant. 



In like manner the disease has been ascribed to bacterial toxins. Fission 

 fungi may be stored up in the living plant and even more in the tubers and in- 

 crease in time, producing a toxin, especially in the spring. 



On the other hand the injurious effect of fatty acids and fusel oil has been 

 assumed as a cause, yet the circumstance that slops of other origin also contain 

 these substances and are not harmful, and that the complaint can be caused by raw 

 potatoes or by potato leaves are against this view. Johne suspected the relatively 

 large amount of potassium salts in the slop (1 liter of distiller's slop contained 

 a]>out 9.-5 grammes of potassium). The symptoms of potassium poisoning (general 

 nuiscular exhaustion and heart weakness) are, however, completely absent, and the 

 idea of a dermatitis caused by potassium has hitherto not been sujiported by a 

 single observation. 



Ziirn's hypothesis that the disease is caused by fission fungi in the feces 

 gaining access to the extremities cannot be accepted, for the disease is not con- 

 tagious, experiments with the intestinal contents not having proved effective in 

 transmitting the disease to healthy animals. Eabe's view that the disease is really 

 a dermatop)hagus scab cannot be acknowledged as correct, since the mites are fre- 

 quently found on the fetlocks of healthy animals and are demonstrable in only 

 about one-third of the cases in sick animals (Johne). Finally there is no confirma- 

 tion of Brautigam's opinion who found the same micrococcus in the slop, in the 

 intestinal contents and in the fluid of the vesicles, and considered that this caused 

 the inflammation of the skin, owing to its increase in the skin and in the sub- 

 cutaneous tissue when the former is soiled by the feces. 



While experiences in general are in favor of the harnilessness of 

 corn and wheat slops, Schroder noticed a considerable outbreak of the 

 disease in a large herd of cattle and also in a horse from feeding on maize 



