724 POISONS : THEIR EFFECTS AND DETECTION. [§§ 936 - 938 . 
out, also, that with regard to the possible lethal effect of a non-corrosive 
salt of alum, presuming that the lethal dose for man is the same as that 
for a cat, the amount of alumina to kill a 68-kilogramme man would 
have to be equal to 17 grins., or about 3 ozs., of ammonia alum. This 
important question can only be settled by careful feeding of animals 
carried on for a long period of time. 
§ 936. Post-mortem Appearances. —In the few cases in which 
persons have been killed by large doses of alum or its salts there have 
been found corrosion of the mouth, throat, and stomach, and hypereemia 
of the kidneys and intestine. In the animals experimented upon by 
Paul Siem, hyperiemia of the intestine, fatty degeneration of the liver, 
and hyaline degeneration of the kidneys were the chief changes noted. 
§ 937. Detection of Alumina. —In all operations for the detection 
of alumina, glass and porcelain vessels are to be avoided. The sub¬ 
stances should be burned to an ash in a platinum dish, the ash treated 
with hydrochloric acid, the acid driven off by heat, and a few drops of 
nitric acid added, and dissolved in hydrochloric acid, and the solution 
boiled and filtered. If organs of the body are operated upon, iron and 
phosphoric acid will be present in the ash ; this will, indeed, be the case 
with most organic substances. The filtered solution is boiled, and, 
while boiling, poured into a strong solution of sodic hydrate contained 
in a silver or platinum dish ; the iron will now separate as oxide, and 
can be filtered off. To the filtrate is added a little sodic phosphate ; it 
is then feebly acidified with hydrochloric acid, and ammonia added just 
sufficient to render it alkaline ; a light whitish cloud of alumina phos- 
phate, should alumina be present, is thrown down, and can be collected, 
thoroughly washed, dried, ignited, and weighed as alumina phosphate. 1 
The alumina phosphate is then fused with sodic sulphate in a platinum 
dish or crucible, and the fused mass treated with hot water ; the sodic 
phosphate dissolves, and the alumina oxide may be filtered off and 
dissolved in a little Irydrochloric acid or sulphuric acid. 
A solution thus prepared has the following properties :— 
Ammonium sulphide : white precipitate of hydroxide. 
Potash or soda : white precipitate, soluble in excess. 
Ammonia : white precipitate, only slightly soluble in excess. 
There is also a blowpipe test : if a little of the hydroxide be collected, 
moistened with cobalt nitrate, and heated on charcoal by the oxidising 
flame, alumina, under these circumstances, becomes of a blue colour. 
5. URANIUM. 
§ 938. Uranium. — The salts of uranium are intensely poisonous. The nitrate of 
uranium is used in photography and the arts, and is a common reagent in chemical 
laboratories. 
1 One part of al. phosphate is equal to 0-42 AL0 3 , 3-733 ammonia alum, and 
4-481 potash alum. 
