On the Psoriasis Or Lepra

to satisfy the earnest inquirer, though, indeed, as to the first named or proximate, writers have for the most part preferred to be silent concerning them. Nor can we hope to resolve all satisfactorily, but nevertheless the fruits of laborious investigation need hardly be thrown away. So, then, as to those that are occasional, external and extrinsic, it is here as with many other disorders, whatever be the organs concerned, these causes may be mostly included under the one head? disturbance. Thus, where the whole system is surfeited with a materies, or primed with a disposition to the dkease, or charged with a capacity for it, it needs but little indeed to throw it into act, to make that manifest which before was scarcely dreamt of. Just as with the concentrated solution of a salt, the mere contact of a glass rod will set it into crystals?just as in water brought slowly to the boiling-point, it may need a little shake before it bursts forth into steam? so where the disposition is strong, as under pressure of a mainspring, it needs but a slight touch to set it going. And thus, indeed, with psoriasis, not otherwise than with eczema, we have seen it come after trifling occasions, as trundling a hoop, or getting wet through in rain, or bathing when hot, or drinking a glass of cold water, or may be after eating spiced food, or playing at snowball and such like?one can scarce enumerate them all; and as to fright from thunderstorm or fire, if we have not such strikin...