i molecular change called pohmierization, whereb}^ a solid form is 
obtained, known as paraformaldehyde or simph^ paraform. When 
■ a solution of formaldehyde is evaporated by heat, and more slowly by 
long standing, paraformaldehyde separates as a white, tlocculent, 
nearly odorless mass, which is almost insoluble in water, alcohol, or 
' ether, and which begins to sublime below 100° C. When heated, 
paraformaldehyde vaporizes and reforms the gaseous formaldehyde. 
It occurs in the market in tablets which are employed for disinfecting 
purposes. 
Formaldehyde is very active chemicalh^; it has a strong reducing 
action on silver, copper, and mercur}^ salts, and unites readily- with 
ammonia, forming the official odorless Hexamethylenamine (which 
see). It is easily oxidized by hydrogen dioxide and potassium per- 
manganate, especiall}^ in alkaline solution. 
Several dusting powders containing formaldehyde, in combination, 
have been introduced; thus, gluiol is a compound of gelatin and for- 
maldehyde, amyloform^ of starch and formaldehyde, etc. 
Formaldehyde is a constituent of maii}^ food preservatives, embalm- 
ing preparations, etc. 
Caution. — Keep well stoppered in a moderately cool place and pro- 
tected from light. 
LIQUOR soon PHOSPHATIS COMPOSITUS. 
Compound Solution of Sodium Phosphate. 
A fairly stable concentrated solution containing 1 Gm. of Sodium 
Phosphate in each Cc. 
Dose. — “Average dose; 8 Cc. (2 fluidrachms).” (U. S. P.) 
Keep well stoppered and moderatelv warm. 
MAGNESII SULPHAS EFFER VESCEXS. 
Effervescent Magnesium Sulphate. 
A similar compound is official under the same name in the British 
Pharmacopoeia; known also as eli'ervescent Epsom salt, and as magnesii 
sulphas granulatus. 
This ma}" take the place of Magnesii Citras Effervescens (U. S. P., 
1890), which has been dropped. 
Dose. — “Average dose: 16 Gm. (210 grains).” (U. S. P.) 
MALTUM. 
Halt. 
This is a reintroduction; Maltum was official in the U. S. Pharma- 
copoeia, 1880, but was dropped in 1890. Used for the preparation of 
Extractum Malti (q. v.). 
