174 



DEFINITION OF TERMS. 



then a maximum; the metal acquires the 

 color of silver, loses its granulated ap- 

 pearance, and assumes a crystallized form. 

 If more carbon is added to the compound, 

 the hardness diminishes in the proportion 

 of its quantity. The affinities of iron 

 and its oxides are arranged by Bergman 

 as in the following table: 



Iron. Oxide of Iron. 



Nickel, Oxalic acid, 



Cobalt, Tartaric acid, 



Manganese, Camphoric, 



Arsenic, Sulphuric, 



Copper, Saciatic, 



Gold, Muriatic, 



Silver, Nitric, 



• Tin, Phosphoric, 



Antimony, Arsenic, 



Platinum, Fluoric, 



Bismuth, Succinic, 



Lead, Citric, 



Mercury, Lactic, 



Acetic. 

 Boracic, 

 Prussic, 

 • Carbonic. 



Irritability {irritahililas ; from irri- 

 to, to provoke; visinsilu of Hailer; vis 

 vita/is of Garter ; oscillation of Boor- 

 haave; tonic power of Stahl; muscular 

 power oi Bell; inherent power oi Cul- 

 len;) the contractility of muscular fibres, 

 or a property peculiar to muscles, by 

 which they contract upon the application 

 of certain stimuli without a consciousness 

 of action. This power may be seen in 

 the tremulous contraction of muscles 

 when lacerated, or when entirely separat- 

 ed from the body. The action of every 

 stimulus is in the inverse ratio to the 

 frequency of its application. A small 

 quantity of spirits, taken into the stomach, 

 increases the action of its muscular coat 

 and also of its various vessels, so that 

 digestion is thereby facilitated. If the 

 same quantity, however, be taken fre- 

 quently it loses its effect. The more the 

 irritability of a part is accumulated, the 

 more that part is disposed to be acted 

 upon. It is on this account that the 

 activity of all animals while in perfect 

 health, is much livelier in the morning 

 than at any other part of the day, for 

 during the night the irritability of the 

 whole fram.e, and especially that of the 



muscles destined for labor, viz: the mus- 

 cles for voluntary action, is reaccumuiat- 

 ed. The same law explains why digestion 

 goes on more rapidly the first hour after 

 food is swallowed than at any other time, 

 and also accounts for the danger that ac- 

 crues to a famished person upon first 

 taking food. 



Irritation {counter,) m medicine con- 

 sists of blisters, hot water, preparations 

 of mustard, and such other substances as 

 cause irritation when applied externally 

 to the human system. 



The principle upon which this class of 

 remedies operate is still a subject of 

 discussion amongst medical practitioners; 

 Cases are stated, where dropsy has been 

 cured by the spilling of boiling water 

 upon the leg of the patient. Another 

 where a person took ten grains of opium. 

 Hot water was applied to the thighs, legs 

 and arms alternately for twenty-four 

 hours; when the patient recovered. He 

 was found at first by his medical attendant 

 in an apoplectic state; tartar emetic and 

 white vitriol failed to produce vomiting. 

 Another person had taken a quantity of 

 prussic acid ; boiling water was poured 

 over his legs without any effect. The 

 legs were then scarified in numerous 

 places and another quantity of boiling 

 water poured over the limbs thus scarified. 

 The first sign of restoration was a slight 

 spasmodic contraction of the muscles, and 

 in a short time spasmodic action took 

 place in many parts of the body. He 

 was ultimately restored to health. The 

 oil of mustard is applied by moistening 

 a piece of flannel or linen with it — the 

 parts contiguous to those effected are 

 selected for the application. The oil is 

 previously diluted. Thirty drops in an 

 ounce of Spt. Vini. or 6 or 8 drops in a 

 dram of ol. amygdalse. It is recommend- 

 ed in chronic rheumatism, neuralgia, pa- 

 ralysis, cholic, &c. If given internally 

 the proportion is 2 drops to a six-ounce 

 mixture. Dose, 5SS. 



Ivory, in natural history, &c. a hard, 

 solid, and firm substance, of a white 

 color, and capable of a very good polish. 

 It is observed that Ceylon ivory and that 

 from the island of Achem do not become 

 yellow from wearing, as all other ivory 

 does. To soften ivory and other bones, 



