DIANA DIARRHCEA. 



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was worshipped there as the symbol of fruitful na- 

 ture, and represented with many breasts, encirclec 

 with numerous bands. 



DIANA of Poitiers, duchess of Valentinois, born 

 in 1499. She was the mistress of king Henry II. ol 

 France, and descended from the noble femily of Poi- 

 tiers, in Dauphiny. At an early age, stie marriec 

 the grand-seneschal of Normandy, Louis de Breze, 

 became a widow at thirty-one, and, some time after, 

 the mistress of the young duke of Orleans. When 

 the duke became dauphin, a violent hostility arose 

 between Diana and the duchess of Etampes, mistress 

 of Francis I., who taunted her rival with her age. 

 Diana satisfied her revenge by banishing the duchess 

 on the accession of Henry II. to the throne, in 1547, 

 in whose name she ruled with unlimited power. Till his 

 death, in 1559. she exercised such an absolute empire 

 over the king, by the charms of her wit and grace, 

 that her superstitious contemporaries ascribed her 

 power to magic. Upon his death, she retired to her 

 castle Anet, where she established a charitable insti- 

 tution for the support of twelve widows, and died in 

 1566. Medals are still to be seen bearing her image, 

 trampling under foot the god of love, with the in- 

 scription, Omnium victorem vifi (I have conquered 

 the universal conqueror). 



DIANA'S TREE (arbor Diance, or silver tree) is 

 formed from a solution of silver in nitrous acid, pre- 

 cipitated by quicksilver, and crystallized in prismatic 

 needles, which are grouped together in the form of a 

 tree. To make this beautiful process of crystalliza- 

 tion visible to the eye, let a quantity of pure silver 

 be dissolved in nitrous acid ; then dilute the saturat- 

 ed solution with twenty or thirty parts of water, and 

 put in an amalgam of .eight parts mercury and one 

 part silver leaf, upon which, after some days, crystals 

 are formed. A little mercury, in fine linen, is sus- 

 pended in this solution by a silk thread, and the tree 

 may then be withdrawn from the solution, and pre- 

 served under a glass bell. Copper filings dropped 

 into a solution of silver in aqua fortis produce the 

 same effect ; and such trees are often found in work- 

 ing silver ore, on the removal of the quicksilver. 

 Since the invention of the voltaic pile, scientific men 

 have succeeded in producing the tree of Diana by 

 its influence on the union of metals with acids. If 

 ,the electric current, for example, is transmitted 

 through nitrate of silver, the needles of silver arrange 

 themselves in the same way on the wire of the pile. 



DIAPASON. By the term diapason, the ancient 

 Greeks expressed the interval of the octave. And 

 certain musical instrument-makers have a kind of 

 rule or scale, called the diapason, by which they de- 

 termine the measures of the pipes, or other parts of 

 their instruments. There is a diapason for trumpets 

 and serpents. Bell-founders have also a diapason, for 

 the regulation of the size, thickness, weight, &c., of 

 their bells. Diapason is likewise the appellation 

 given to certain stops in an organ. See Stop. 



DIAPER (French, diapre); so called from Ypres 

 (J' Ypres) ; linen cloth woven in flowers and other 

 figures ; the finest species of figured linen after 

 damask. Hence, as a verb, it signifies to diversify 

 or variegate with flowers, or to imitate diaper. 



DIAPHRAGM, in anatomy ; a large robust, mus- 

 cular membrane or skin, placed transversely in the 

 trunk, and dividing the chest from the belly. In 

 its natural situation, the diaphragm is convex on the 

 upper side towards the breast, and concave on its 

 lower side towards the belly ; therefore, when its 

 fibres swell and contract, it must become plain on 

 each side ; and consequently the cavity of the breast 

 is enlarged, to give liberty to the lungs to receive 

 air in inspiration ; and the stomach and intestines are 

 pressed for die distribution of their contents ; hence 



the use of this muscle is very considerable. It is tie 

 principal agent in respiration, particularly in inspira 

 tion ; for, when it is in action, the cavity of the chest 

 is enlarged, particularly at the sides, where the lungs 

 are chiefly situated ; and, as the lungs must always 

 be contiguous to the inside of the chest and upper 

 side of the diaphragm, the air rushes into them in or- 

 der to fill up the increased space. In expiration, it is 

 relaxed, and pushed up by the pressure of the abdomi- 

 nal muscles upon the viscera of the abdomen ; and at 

 the same time that they press it upwards, they pull 

 down the ribs, by which the cavity of the chest is dimi- 

 nished, and the air suddenly pushed out of the lungs. 



DIARRHCEA ; a very common disease, which 

 consists in an increased discharge from the alimen- 

 tary canal, the evacuations being but little affected, 

 except in their assuming a more liquid consistence. 

 They are generally preceded or accompanied by fla- 

 tulence, and a griping pain in the bowels, and 

 frequently by sickness ; but this should, perhaps, ra- 

 ther be attributed to the same cause which produces 

 the diarrhoea, than be considered as a part of the 

 disease itself. The symptoms of this complaint are so 

 obvious as seldom to leave any doubt respecting its 

 existence ; but there are two diseases that resemble it, 

 and from which it is important to distinguish it dysen- 

 tery and cholera. For the most part, an attention fo 

 the nature of the evacuations is sufficient to point out 

 the distinction ; or if, as occasionally happens, the 

 diseases appear to run into each other, our remedies 

 must be administered accordingly, always adapting 

 them rather to the symptoms than to a technical 

 nomenclature. 



The exciting causes of diarrhoea are various ; per- 

 haps the most frequent is repletion of the stomach or 

 the reception into it of some kind of indigestible food : 

 cold applied to the surface of the body, and especially 

 to the legs and feet, is also an exciting cause of diar- 

 rhoea ; and it is occasionally produced by impressions 

 upon the nervous system, or even by mere mental emo- 

 tions. In children, the peculiar irritation produced by 

 teething seems to be a frequent exciting cause of diar- 

 rhoea, as well as that which arises from the presence of 

 worms in the alimentary canal. Diarrhoea is often 

 symptomatic of some other disease : of these, one of 

 the most violent is the colliquative discharge from 

 the bowels which occurs in the latter stages of hec- 

 tic fever. It is also a frequent attendant or sequel of 

 the affections of the liver that come on after a resi- 

 dence in hot climates, and is then found to be one of 

 the most unmanageable symptoms of these diseases. 



In its simple form, diarrhoea is not difficult of cure, 

 and, perhaps, in a great majority of cases, would be 

 relieved by the mere efforts of nature. The proxi- 

 mate cause of diarrhoea appears to be an increase ot 

 the peristaltic motion of the intestines, which may 

 depend either upon a stimulating substance applied 

 to them, or upon an increased sensibility in the 

 part, rendering it more easily affected by the ordi* 

 nary stimuli. In cases of the first description, which 

 constitute a great majority of those that fall under 

 our observation, the most effectual remedies are mikl 

 purgatives, given in small doses, and frequently re- 

 peated. Along with the purgatives large quantities 

 if mild diluents will be found serviceable ; and the 

 food should be of the least stimulating kind, and 

 3e composed as much as possible of liquids. The 

 ihoice of the purgatives will depend upon the state 

 of the stomach, and various other circumstances : 

 leutral salts, castor oil, rhubarb and magnesia, are, 

 jerhaps, among those that are the most generally 

 ipplicable : the last will be especially proper when 

 we have reason to suspect an acid state of the ali- 

 mentary canal. After the due exhibition of purga- 

 tives, we shall generally find the complaint to subside 



