There is no doubt that, however absorbed, lead remains stored up in the body in minute quantities in many places, and the close analogy to arsenic is met with in the curious elimination of the metal by the fæces. Cloetta[17], quoted by Dixon Mann, discovered that, although dogs were unable to take a larger dose of arsenic than 0·0035 gramme per day without exhibiting toxic results, they could nevertheless take arsenic in much larger doses if it were given in the solid form, and he was able to increase the dose to as much as 2 grammes per diem without showing any toxic symptoms. Examination of the urine and fæces showed that as the amount of urinary excretion of arsenic diminished, so that in the fæces increased, and in lead poisoning, even in massive doses swallowed in error, the amount of lead excreted by the urine rapidly diminishes in quantity, although the patient may be still suffering from the effects of lead poisoning. The experiments, also, quoted on p. 100 constantly pointed to the elimination of lead by way of the intestine, and in practically all the animals that had suffered from chronic poisoning well-marked dark staining of the upper part of the cæcum due to lead was invariably present. This staining and excretion of lead of the large intestine undoubtedly takes place in man. In a case described by Little[18], where diachylon had been administered, the administration of a large enema containing sulphate of magnesium came away black. A more detailed result of the experiments and a consideration of the elimination of lead are reserved for another chapter, but it is impossible to consider the ætiology of the disease without some reference to the general histological channels of absorption and excretion. =Cutaneous Absorption of Lead.=--A considerable amount of controversy has centred on the question of the absorption of lead through the unbroken skin. It has been shown that such drugs as belladonna applied to the skin alone may produce dilatation of the pupil; an ointment containing salicylic acid spread upon the skin and thoroughly rubbed in is followed by the appearance of derivatives of salicylic acid in the urine; mercury may be applied to the skin, and rubbed in, in sufficient quantities to produce salivation; and a very large number of other drugs may be cited, all of which when applied to the unbroken epidermis with friction produce the physiological action of the drug.