“When I visited last year the prisons of Paris with my friend Villermé, who was interested in prisons generally, I was extremely surprised at the proportion of sick in the hospital of St. Lazarus, relatively to the whole population of the prisons. The prison, uniting all the conditions necessary to health as regards its position, construction, the dress and food of the prisoners, who were constantly kept at work, how explain the much greater proportion of sick to what we remark in other prisons of a bad condition, and in which are found united all the apparent causes of unhealthiness?—This, I must confess, has baffled all calculation, and has driven every one to say that there must be a cause for the peculiarity, but that it could not he discovered. I do not despair to have hit upon that cause, and I believe it is to be recognised in the nature of the water drunk by the prisoners. Having tasted it in the wooden reservoir behind the house, which was in bad order, and full of plants of the genus confervæ, I found it had a detestable and truly repulsive taste, a circumstance which does not appear to have been hitherto remarked. Might not the cause, then, he detected in the chemical nature of the water of Belleville and of the neighbourhood of St. Gervais, of which the prisoners drink exclusively? What proves it is the striking resemblance which exists in this respect between the water of Belleville and that in the wells of the entrance-court of the hospital of the Salpêtriere, which both contain a very great proportion of sulphate of lime, and other purgative salts. Now the venerable Professor Pinel and his pupil Schwilgué have remarked for more than 20 years the influence that the water of the wells of which I speak has upon the portion of the population of the hospital who make use of it, and they believe that certain affections connected evidently with locality cannot be attributed to any other cause, and particularly the disposition to chronic diarrhœa which is so often observed in this hospital. It turns out upon examination _that the greater part of the sick who fill the infirmary of the prison of St. Lazarus are brought there for illnesses of the same identical nature_. In the prison they are obliged to have recourse to the water of the Seine to cook the vegetables and other food, an evident proof of the truth, or at least the probability, of all I have just advanced.”