CHAPTER V. 



PHOSPHORUS — PHOSPHORETTED HYDROGEN — ARSENIURETTED 

 HYDROGEN— ARSENIOUS SULPHIDE— ARSENIOUS ACID— WHITE 

 ARSENIC— ARSENIC ACID— BORIC ACID. 



II. Phosphorus. — Preparation. — Phosphorus does not occur in 

 nature in the free state, hut as phosphoric acid combined with various 

 metallic oxides, lime, magnesia, soda, etc. In the industrial manu- 

 facture hones form the raw material. 



Properties. — Phosphorus insoluble in water and alcohol dissolves 

 in carbon disulphide. It is combustible. It oxidizes in the air at the 

 ordinary temperature but does not ignite below 60° C. (140° F.). It 

 melts at 44° C. (111-2° F.). It is preserved under water. Phosphorus 

 is a violent poison which, when absorbed even in very small doses, 

 induces vomiting and epigastric pains. It may act if it continue to be 

 absorbed on the nervous system, which it depresses, and by paralysing 

 the heart's action, it rapidly causes death. The intensity of the action 

 of phosphorus depends on the form under which it is ingested ; dis- 

 solved in oil, for example, it is much more poisonous than when in 

 solution in other solvents, because in this form it is precipitated less 

 easily in the aqueous juices of the stomach. 



Use. — Phosphorus is as violent a poison for mammals as for 

 insects. It is used everywhere where pastes can be used to destroy 

 noxious animals. To prepare these pastes 50 oz. of boiling water 

 are run into a porcelain mortar, then 2 oz. of phosphorus which soon 

 melt therein ; 40 oz. of flour are then added whilst stirring with a 

 wooden spatula. When the mixture is almost cold 40 oz. of molten 

 tallow still tepid are run in and 20 oz. of sugar. This paste may be 

 used indifferently against rodents and certain injurious insects. The 

 Murides, such as Arvicola (field mice), Miis musculus (domestic 

 mouse), Mtis agrarius (field mouse), Mus ratus (ordinary rat), Mus 

 decimiamcs (Surmulot rat), are destroyed by the phosphorus pastes, 

 the preparation of which is given above. Mohr adds a little glycerine 

 which preserves them longer in the air. With this poisonous paste 

 slices of toasted bread are coated which the rodents eat without sus- 

 picion. According to Crampe it suffices to prepare a paste of boiled 

 flour which is cooled to 43' C. (109-4° F.) before mixing in the phos- 

 phorus ; pieces of straw are then dipped into the paste and laid in the 

 burrow or in the run of the rodents. The latter in trying to remove 

 them or in walking on them get daubed with pieces of paste on the 

 hair, and are poisoned by licking themselves. 



Amongst the insects killed by phosphorus are : Perlplaneta orien- 

 talis (cockroach). This insect does great damage in hothouses by 



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