Such are some of the eddies in which we are liable to become involved and carried back out of the broad stream of philosophical, or, in other words, truth-loving, investigations.  The causes of disease, in the mean time, have been less earnestly studied in the eagerness of the search for remedies.  Speak softly!  Women have been borne out from an old-world hospital, two in one coffin, that the horrors of their prison-house might not be known, while the very men who were discussing the treatment of the disease were stupidly conveying the infection from bed to bed, as rat-killers carry their poisons from one household to another.  Do not some of you remember that I have had to fight this private-pestilence question against a scepticism which sneered in the face of a mass of evidence such as the calm statisticians of the Insurance office could not listen to without horror and indignation? ["The Contagiousness of Puerperal Fever.”—­N.  E. Quar.  Jour. of Medicine and Surgery, April, 1843.  Reprinted, with Additions.  Boston:  Ticknor & Fields. 1855.] Have we forgotten what is told in one of the books published under our own sanction, that a simple measure of ventilation, proposed by Dr. John Clark, had saved more than sixteen thousand children’s lives in a single hospital?  How long would it have taken small doses of calomel and rhubarb to save as many children?  These may be useful in prudent hands, but how insignificant compared to the great hygienic conditions!  Causes, causes, and again causes,—­more and more we fall back on these as the chief objects of our attention.  The shortest system of medical practice that I know of is the oldest, but not the worst.  It is older than Hippocrates, older than Chiron the Centaur.  Nature taught it to the first mother when she saw her first-born child putting some ugly pebble or lurid berry into its mouth.  I know not in what language it was spoken, but I know that in English it would sound thus:  Spit it out!

Art can do something more than say this.  It can sometimes reach the pebble or berry after it has been swallowed.  But the great thing is to keep these things out of children’s mouths, and as soon as they are beyond our reach, to be reasonable and patient with Nature, who means well, but does not like to hurry, and who took nine calendar months, more or less, to every mother’s son among us, before she thought he was fit to be shown to the public.

Suffer me now to lay down a few propositions, whether old or new it matters little, not for your immediate acceptance, nor yet for your hasty rejection, but for your calm consideration.

But first, there are a number of terms which we are in the habit of using in a vague though not unintelligible way, and which it is as well now to define.  These terms are the tools with which we are to work, and the first thing is to sharpen them.  It is nothing to us that they have been sharpened a thousand times before; they always get dull in the using, and every new workman has a right to carry them to the grindstone and sharpen them to suit himself.