ECZEMA DUE TO FEEDING WITH POTATO PULP.
Among the forms of eczema due to toxins, several varieties may be recognised. Some result from the administration of drugs such as iodine, others from special forms of food. The only one of clinical importance is that following the consumption of excessive quantities of potato pulp.
Causation. The disease is seen in all districts in which potatoes are employed for the manufacture of alcohol and starch, more especially in Germany. The disease seems to be a direct consequence of feeding with residual products of distilleries and starch manufactories.
Spinola states that 160 lbs. of potato refuse per day to 1,000 lbs. of body weight would certainly produce eczema: 60 to 80 lbs. only produce it in rare cases and 20 to 40 lbs. are harmless.
There is a further point to consider as regards the variation of potato pulp in toxicity. Potatoes yield a more or less active residue, according to the year in which they are grown, their state of germination, and the variety to which they belong. Raw or cooked potatoes may produce eczema if given in large quantities or for long periods.
Numerous theories have been advanced as to the nature of the morbid disturbance producing eczema. Some authorities declare the appearance of the disease to be due to the presence of a toxic principle contained in potatoes, viz., solanin. It might be objected that this chemical principle only exists during germination while potatoes that have not undergone germination produce the disease. Further, the symptoms of poisoning by solanin differ from those of this form of eczema, among which loss of appetite, for instance, or stupefaction, or narcosis is never observable.
According to other writers eczema is due to the action of the lower alcohols contained in the refuse pulp, but again these properties exist in brewers’ and distillers’ grains, the consumption of which produces no bad results. Similar objections might be made regarding the suggested action of the acids of fermentation (lactic, butyric, and acetic acids, etc.).
Johne blames the salts of potassium, which, however, can only act as digestive irritants, and Zürn suggests mycosic inflammation.
Whatever the toxic principle, its effects are most marked in animals undergoing fattening, and are rarely found in working oxen, still more rarely in milch cows. In the last named the injurious principle appears to be eliminated in the milk, and this theory is supported by the fact that the liquid has purgative properties; the calves which consume it suffer from diarrhœa, which ceases when the feeding is altered.
Finally, it has been proved that different animals show different degrees of susceptibility to the action of potato pulp.