The cause to which the various authorities and Medical Officers of Health directly attributed it was the one immediately before their eyes--namely, the pulling down of houses which hitherto had afforded shelter, of a sort, to the people. As the Medical Officer of Health for St. Olave, Southwark, said (1860-1):-- "To effect street improvements--to build warehouses, or for some other purpose--the habitations of the working classes are broken up without any provision being made for them elsewhere. They are therefore driven by necessity to crowd into other houses in the same neighbourhood perhaps already overcrowded." An actual illustration was the case reported by the Medical Officer of Health for Limehouse:-- "The London Dock Company have, for the purpose of enlarging and improving their docks, pulled down not less than 400 houses in the parish of Shadwell, the homes of not fewer than 3,000 persons of the poorer classes. "... The neighbouring parishes are now suffering from an augmentation of their already overcrowded population." The District Board of St. Saviour, Southwark, stated that the evil of overcrowding "can scarcely be exaggerated, whether it be regarded in a physical, mental, or moral aspect." The principal of the causes are:-- "(1) The arbitrary power exercised by railway companies in ejecting the labouring classes from their homes without any obligation to provide for their domestic convenience. "(2) The existing law of (poor law) removal, any break in the three years' residence in the parish rendering them liable to removal to other distant parishes." The latter had, however, most probably, but very small effect. A great cause was that described by the Medical Officer of Health for Shoreditch:-- "There is a constant and rapid flow of population into Shoreditch. It is in this circumstance that I see one of the most alarming dangers to the health of the district. "The area does not enlarge, and yet year after year dense crowds of human beings are packed and squeezed into that limited area. The growth of the population has far outstripped the growth of the house accommodation. "The immense majority of the immigrants are precisely of that class which most largely increases the dangers of disease by thickening the population. You are largely burdened with the pauperism of other and wealthier districts. The burden is doubly grievous; for it taxes your property, your labour, and gives strength to the elements of disease amongst you. "It is probable that there is no spot in London more crowded with life than many places in Holywell or St. Leonard's. "Typhus--a disease more terrible than cholera--has made itself at home in the parish." And the Medical Officer of Health for Fulham wrote (1857):-- "... The daily necessities of the labourer's family draw so heavily on his earnings as to leave only a very small sum for the payment of rent, and hence the most limited house accommodation is sought for and endured...."