But, neither agriculture, commerce, nor manufactures are the only things necessary to build up a large city. Healthiness is more important than either. Here again, Mackinaw has more advantage over Chicago. Mackinaw has been proved by two hundred years experience to be one of the healthiest points in America. Chicago is generally healthy, but is subject to more severe epidemics. The cholera visited it in 1832 and in 1849, with fearful force; while its very low position and muddy streets expose its inhabitants to those diseases which arise from damps. The Legislature of Michigan, recently passed a bill to provide for the drainage and reclamation of the swamp lands of the State by a system of State roads, accompanied by a lengthy and able report. The bill provides among others, a road from Ionia north to the straits, and thence to Saut St. Mary. They also passed a bill entitled the "Forty Acre Homestead Act." This act requires the commissioners of the State Land office to issue a certificate of purchase to every settler on the swamp lands belonging to the State, for forty acres of said lands, whenever such settler shall have resided upon it for five continuous years, and when he has drained the same so as to comply with the provisions of the Act of Congress making this grant to the State. Before the settler can acquire the right thus to occupy and drain any of the swamp lands, he is required to file with the commissioner his application, accompanied by an oath of his intention to settle upon and drain it for the purpose of obtaining a title thereto. And he must also make oath that he is not already the owner of forty acres of land in any State of the United States. It is also expressly provided that he shall not cut or carry away any timber from said land, unless it be to clear it for cultivation, under such penalties as are now prescribed for trespassing upon State lands. It will be seen, therefore, that the object of the law is to provide homes for the homeless, and at the same time promote the actual, _permanent_ settlement of the northern portion of the State. No man who possesses forty acres of land either in Michigan or anywhere else, is entitled to the benefits of the act. It is emphatically a law for the poor man. To all such it secures a _home_, without money and without price. All it requires of him is to settle upon and cultivate it. How many are there in Detroit and other portions of the State, who will avail themselves of this beneficent republican measure? CHAPTER XII. The Great Western Valley -- Its growth and population -- Comparison of Atlantic with interior cities -- Relative growth of river and lake cities -- Centre of population -- Lake tonnage -- Progress of the principal centres of population. The following chapter on the population and growth of the Great Western Valley is taken from De Bow's Review:--