For the purposes of controlling the experiments of inhalation, two other series of experiments were undertaken. In one instance an animal was fed for two years on white lead; the animal was given 0·1 gramme per day, and this was increased up to 0·5 gramme, and ultimately 1 gramme. This animal exhibited no symptoms whatever of lead poisoning, and when it was killed, at the end of the time of experiment, showed no apparent lesion, with the exception of very marked staining of the colon and vermiform appendix. This staining of the large intestine and the appendix, the engorgement of the vessels, particularly of the omentum and mesentery, the enlargement of the lymphatic glands in the neighbourhood of the colon, ileo-cæcal valve, and appendix, suggest the absorption of lead in the upper part of the intestine, and its discharge or elimination into the large intestine. That lead is absorbed into the upper part of the intestine was demonstrated in the following manner: An animal was anæsthetized, an incision made, and a loop of intestine pulled up and clamped off, a solution of lead chloride being run into the loop by means of a hypodermic syringe. The mesenteric vein passing from this loop of intestine was then carefully secured, a small opening made in it, and the blood collected drop by drop until some 40 c.c. had been collected, the time occupied being about three-quarters of an hour. The blood thus collected was submitted to chemical examination, and lead was demonstrated to be present. Lead therefore passes direct from the intestine into the portal circulation. In only one of the feeding experiments with solid compounds of lead was any definite symptom of lead poisoning produced, and in this instance the compound used was dust collected from the flues of a blast-furnace. This dust was afterwards found to contain a considerable quantity of arsenic. The experiment cannot therefore be regarded as conclusive. With the more soluble salts of lead, however, such as the acetate, lead poisoning may be set up by means of lead administered via the intestinal canal: 1 gramme of lead acetate administered by means of a hypodermic syringe through a catheter passed into the stomach of a cat produced abortion in ten days, and death in three weeks. Four grammes of acetate produced a similar effect in a dog in four weeks. PLATE III [Illustration: FIG. 1.--KIDNEY OF ANIMAL POISONED WITH WHITE LEAD (INHALATION), SHOWING MICROSCOPICAL HÆMORRHAGES. (STAINED HÆMATOXYLIN AND EOSIN.) × 250.] [Illustration: FIG. 2.--KIDNEY OF MAN DYING OF CHRONIC LEAD POISONING. (STAINED HÆMATOXYLIN AND EOSIN.) × 250.] [Illustration: FIG. 3.--BRAIN OF YOUNG WOMAN DYING OF ACUTE LEAD ENCEPHALOPATHY, SHOWING SMALL CEREBRAL HÆMORRHAGES. (STAINED HÆMATOXYLIN AND EOSIN.) × 250.]