The chemical estimations of the quantity of lead found in the kidney of persons who have died of lead poisoning given by different observers, vary exceedingly. Even in cases of definite lead poisoning, where there can be no reasonable doubt as to the diagnosis, many cases are on record where no lead at all has been discovered in the kidney. It is not acute nephritis which is seen in lead poisoning, but the chronic cirrhotic variety. This probably takes a very long time to develop; indeed, animals kept under the influence of lead for two years show very little kidney destruction. It is quite possible that in the kidney disease met with in lead-workers the combined effect of alcohol with lead is really the causative factor. There is not sufficient statistical evidence to make a definite statement on this point, and it would only be possible by comparing the records of the autopsies of a number of persons working in lead who do not die from lead poisoning, and who were non-alcoholic, with a similar number of persons who, in addition to their lead absorption, were alcoholic subjects. It is unusual to find blood in the urine, and the condition of the kidney does not suggest that it would be present. Gull and Sutton[42] have described arterio-capillary fibrosis in which the intima of the larger vessels became greatly hypertrophied, and many of the smaller vessels are practically destroyed by obliterative arteritis. The production of arterio-sclerosis, with attendant thickening of the vessel walls and with the various symptoms commonly associated with arterio-sclerosis, were regarded as secondary symptoms of lead poisoning. The action of lead on the vessel walls themselves thus independently proved by a large number of observers working at different aspects of the problem suggests the pathological change in the vessels as the common element in the cause of these diverse symptoms of lead poisoning--colic, paralysis, mania. Generally speaking, however, the attention of most has been rather focussed on the kidney and the degenerative changes occurring in that organ due to the irritative action of lead in the process of excretion than on the vessels themselves.