IN CHEMISTRY. 1 17 



13. Why are matches poisonous ? What is the anti- 

 dote? 



(See Physiology, page 209.) 



Because of the phosphorus in the match. 



virtue of this character, it u may follow the blood in its changes, may oxidize 

 in the one great set of capillaries, and be indifferent to oxygen in the other ; 

 may occur in the brain, in the vitreous form, changing as quickly as the 

 intellect or imagination demands, and literally flaming that thoughts may 

 breathe and words may burn ; and may be present in the bones in its amor- 

 phous form, content like an impassive caryatid, to sustain upon its unwearied 

 shoulders the mere dead weight of stones of flesh. And what is here said of 

 the brain as contrasted with the bones, will apply with equal or similar force 

 to many other organs of the body. All throughout the living system, we 

 may believe that phosphorus is found at the centres of vital action in the 

 active condition, and at its outlying points in the passive condition. In the 

 one case it is like the soldier with his loaded musket pressed to his shoulder 

 and his finger on the trigger, almost anticipating the command to fire ; in the 

 other it is like the same soldier with his unloaded weapon at his side standing 

 at ease." 



" Further, phosphorus forms with oxygen a powerful acid, capable even of 

 abstracting water from sulphuric acid, and yet perfectly unirritating to the 

 organic textures. Taking up varying quantities of water, phosphoric acid 

 assumes no fewer than three distinct forms, which will unite with one, two, 

 or three atoms of alkali respectively, giving an acid, neutral or alkaline reac- 

 tion. Thus it is available for the most varied uses in the body. A child is 

 beginning to walk, and the bones of its limbs must be strengthened and 

 hardened ; phosphoric acid, accordingly, carries with it three units of lime to 

 them, and renders them solid and firm. But the bones of its skull must 

 remain comparatively soft and yielding, for it has many a fall, and the more 

 elastic these bones are, the less will it suffer when its head strikes a hard 

 object ; so that in them we may suppose the phosphoric acid to retain but two 

 units of lime, and to form a softer, less consistent solid. And the cartilages 

 of the ribs must be still more supple and elastic, so that in them the phos- 

 phoric acid may be supposed to be combined with but one unit of base. On 

 the other hand, its teeth must be harder than its hardest bones, and a new 

 demand is made on the lime-phosphates to associate themselves with other 

 lime-salts (especially fluoride of calcium), to form the cutting edges and 

 grinding faces of the incisors and molars. All the while, also, the blood must 

 be kept alkaline, that oxidation of the tissues may be promoted, and albumen 

 retained in solution ; and yet it must not be too alkaline, or tissues and albu- 

 men will both be destroyed, and the carbonic acid developed at the systemic 

 capillaries will not be exchanged for oxygen when the blood is exposed to 

 that gas at the lungs. So phosphoric acid provides a salt containing two 



