In 1790 there was 1 person to 1755 square feet. 1800 ” 1 ” 1216 1810 ” 1 ” 933 1820 ” 1 ” 986 1830 ” 1 ” 623 Viewing the wards separately, we find that, in 1830, there was one inhabitant to every 313 square feet of superficies in the eastern division, and one to 979 of the western. Eastern Wards. New Market ward had 1 to 236 Lower Delaware 1 243 Pine 1 248 Upper Delaware 1 318 Chesnut 1 341 Walnut 1 398 High 1 402 Dock 1 416 --- Average 313 In the western wards, where there is a large proportion of unoccupied ground, the density varies from 840 to 1354 square feet to each inhabitant--the average being 979. The propriety of legislative enactments limiting the maximum density of population, and the space allowed to be occupied by buildings, so as to ensure sufficient ventilation, &c. seems to us to be manifest. We shall take a future opportunity of offering some further remarks on this subject. _Injection of Saline Solutions into the Veins._ (Continued from page 55.) No. 4. _Letter from Dr. Lewins, to the Secretary of the Central Board of Health._ _Results of the Injection Practice in the Drummond-street Cholera Hospital, Edinburgh._ SIR,--You will receive from Dr. Latta, the details of two or three cases treated by saline injections. We have both been so much occupied to-day, that we have not had leisure to get our communications ready to be sent in the same envelope. We steal an hour from the time usually allotted for rest to write to you. In case Dr. Latta should omit to mention the circumstance, I beg to mention that his patient, Cousins, the woman who was injected to the amount of three hundred and seventy-six ounces, and who promised to do well, for a considerable time, was a person of very dissipated habits. In the Drummond-street hospital six patients have been injected, and three recovered, or are recovering. In the three that died, extensive organic disease was found on dissection; disease that had existed previously to the attack of cholera. I send herewith the report of two cases, treated by Dr. Craigie of this place, which, at my request, he furnished me to-day for the perusal of the Board. I intended to have sent an account of an interesting fatal case, the only one in which the venous injection may be said to have fairly failed where it was fairly used; that I shall do to-morrow. I have the honour to be, sir, your most obedient servant. ROBERT LEWINS, M. D. _Leith, May 27th._ No. 5. _Details of Two Cases of Malignant Cholera treated by Venous Injection, by Dr. Craigie, of Leith._