516 



DISEASES OF THE SKIN. 



marked according to age, seems also to depend upon a number of 

 conditions: variations in fermentation and its products, diversity 

 of species or growth of the potato, composition of the soil, manuring, 

 etc. ; it is possible that, as with lupin, the injurious quality varies 

 with the soil where the tuber has grown. According to Peiffer, 

 malts which have been subjected to a too rapid distillation would 

 be particularly hurtful ; their acidity does not seem to play any 

 etiological rôle. According to Baranski the disease made its ap- 

 pearance in Galicia after the introduction of Gleason's potato in 

 that country. 



The disease which is here considered is not exclusively produced 

 by malts ; raw or cooked potatoes, especially those in course of 

 germination, stalks of the plant, water used for cooking purposes, 

 and acid fermented matters may also occasion it. From this fact 

 we must infer that the potato itself contains a noxious agent, which 

 remains in the residues in a quantity relatively more considerable 

 than in the tuber itself, the carbo-hydrates of which have passed 

 into alcohol. ÎTothing certain is known concerning the nature of 

 this agent ; it is generally admitted that at the time of its elimina- 

 tion by the skin it irritates the latter, inflames it, and thus deter- 

 mines an eczema. If milch cows are rarely affected, it is probably 

 due to the elimination of the toxic principle through the very 

 active lacteal secretion. Among the facts establishing that milk 

 from sick cows is certainly harmful, we may mention that it pro- 

 duces diarrhea in calves (Johne), and occasions an eruption in 

 children.^ We have observed that the affection is generally of a 

 benign character in working animals ; it is very likely that cuta- 

 neous excretion of the pathogenic agent diminishes its force, aided 

 also by a corresponding elimination on the part of the various 

 secretory organs under the influence of exercise. This theory has 

 been objected to on account of the ordinary appearance of eczema 

 on the hind legs. But this may first invade different regions of 

 the body ; and, on the other hand, we must take into account the 

 relative delicacy of the skin of the extremities compared with that 

 of the trunk, as well as the irritation exerted upon the posterior 

 extremities by the liquid and even diarrheal excrements dejected by 

 animals fed on malts, in which condition these members are kept 

 in a constant state of dampness and uncleanliness. This weakened 

 resistance of the skin of the extremities to medicamentous exanthema 



1 Hering : Jahrbuch fiir Kinderheilkunde, 1873. 



