so by preventing the formation of ship-miasma (as easy of accomplishment as the other) ship-fever will in like manner be prevented.
"What, then, are the circumstances which give rise to this typhus-breeding miasma? There are certain conditions essential to its creation, which I will enumerate in the order of their importance, beginning with the least:
"I. The confinement of people in apartments disproportioned in size to the requirements of wholesome respiration.
"II. The retention in the same apartment of the excretions from the bodies of the individuals thus confined; such as the matter of perspiration and other more offensive excretions. These, acted on by the artificial heat of the apartment, or even by the natural heat of the bodies alone, will become decomposed, and produce an effluvium which will react poisonously on the persons exposed to it.
"III. The exclusion of pure air.
"As to the first of these causes, the number of persons and the size of the apartment necessary to produce the miasma are merely relative. An apartment may be crowded without danger from this source, provided that from the first ventilation and cleanliness be thoroughly and constantly maintained.
Explanation of its virulence in steerage"With this brief explanation of the general causes of typhus, the reasons for its prevalence in the steerages of passenger-ships are very apparent. In great numbers of them, all the conditions enumerated above, as necessary for the creation of this disorder, are found to exist, and it is reasonable to infer the existence of Specific causesome specific cause in addition to the general ones which have been mentioned.
"We find ship-fever, within a few years, to have prevailed most frequently and extensively in those vessels which ply between several ports of Great Britain and this country, and this fact, together with an examination of the passengers, points Famine.unerringly to the famine which desolated a large section of that kingdom as the additional cause alluded to.
