558 MEDICAL JURISPRUDENCE

3 A borax bead, dipped in a solution of a manganese compound, imparts an
amethyst colour in the oxidizing flame, but it becomes colourless m the reducing flame.

4. A solution of potassium permanganate is decolourized when it is heated with
dilute sulphuric acid and oxalic acid.

Medico-Legal Points.—Acute poisoning by potassium permanganate is rare, although
a few accidental and suicidal cases have occurred.

Chronic poisoning by manganese occurs only when the concentration of manganese
in the working atmosphere exceeds 50 mg. per cubic metre/'t Chronic poisoning is
regarded as an industrial disease in European countries, but it is not included in the list
of occupational diseases in India under the Workmen's Compensation Act, 3923.

Manganese is not an essential constituent of the human body, but it is found in
minute traces in the human blood and tissues, and it is taken into the system with the
food in which it is present in traces.

Manganese is excreted mainly in the fasces, bile and to a small extent in the urine,

TIN (KALA1)

The only salts that are of any toxicological interest are stannous and stannic
chloride. They occur as whitish-yellow crystals, but being deliquescent, are met with
in acid watery solution. A mixture of these two chlorides in solution is known as
Dyers3 Spirit and is used as a mordant in calico-printing*

Symptoms.—A metallic taste in the mouth; nausea accompanied by vomiting; pain
in the abdomen; purging; feeble, irregular pulse ; cyanosis ; headache ; great depression;
collapse; unconsciousness or drowsiness.

Fatal Dose.—Not known. Half a drachm of tin chloride solution has caused death,
Four to ten grains of mallate of tin have proved fatal in children,

Fatal Period.—Not known.

Treatment—Emetics or the stomach tube should be used, Eggs, bland demulcent
drinks, stimulant's and anodynes should be next administered.

Post-mortem Appearances.—Not known; probably those of gastroenteritis,

Chemical Tests.—1. Sulphuretted hydrogen yields with stannous solutions a dark
brown precipitate, and with stannic solutions a yellow precipitate. Both precipitates are
soluble in ammonium sulphide.

2. Mercuric chloride gives a white precipitate with a stannous salt, which turns
grey and lastly black on boiling with excess of the reagent.

3. Gold chloride produces a purple precipitate with a stannous salt, but none with
a stannic salt.

Medico-Legal Points.—1. Poisoning by tin salts is very rare indeed. Accidental
cases occur from the use of tinned fruits owing to the mallic acid of fruits acting on tin
and forming mallate of tin.

Poisonous symptoms may arise from wearing silk articles of clothing, such as silk
stockings, which are sometimes impregnated with tin chloride. A, Jolles r'n reports the
case of a young woman who developed poisonous symptoms from wearing yellow silk
stockings heavily impregnated with tin chloride. She complained of motor and sensory
disturbances in the lower extremities which were stained yellow. The urine was albu-
minous, and marked nervous symptoms like ataxia were noted a few weeks later. She
became anaemic, but recovered in a few months after the stockings had been discarded.

A fatal case se of poisoning has occurred from the accidental use of " putty powder ",
a higher oxide of tin, which is used for polishing silver vessels,

2. Tin is eliminated in the urine and faeces.

CHROMIUM

The following preparations of chromium are important from a toxicological point
of view: — , o JT

Chromic Acid (Chromic Anhydride, Chromium Trioxide), CrO*,—This occurs as
crimson needle-shaped crystals. It is deliquescent and readily soluble in water and
may explode when brought into contact with glycerin, ether or alcohol. It is a powerful
S^"S af ' i ? u-sed *5i PreParing ^quor acidi cHromlci -It is prepared by the
action of strong sulphuric acid on a cold saturated solution of potassium bichromate,

1941! M' B' JaC°bS' Analytical Ctemtetn/ of Industrial Poisons, Hotard* and Solvents,