170 ‘ REPORTS ON THE STATE OF SctENcE.—1918. 
No. 11,771/1912. EK. Podszus, Preparation of sols. 
No. 14,235/1912. B. Schwerin, Preparation of sols. 
No. 29,049/1912. Ges. f. Elektro-Osmose, Preparation of sols. 
No. 7238/1913. Aktiebol: KolJloid Preparation of Colloidal , 
Sulphur. 
No. 9287/1914. Ges. f. Klektro-Osmose, Preparation of Colloidal 
Silica. 
No. 9261/1914. Ges. f. Elektro-Osmose, Preparation of Metal sols 
with silica. 
No. 15,267/1914. Ges. f. Elektro-Osmose, Preparation of Metal sols. 
No. 15,127/1915. Soc. Chem. Ind. Basle, Preparation of Colloidal 
Copper. 
No. 104,609 (1917). Monneron & Guye, Preparation of Colloidal 
Alumina gel. 
Colloids and Synthetic Compounds. 
There is no necessary incompatibility between colloidal sols and 
synthetic compounds which are not regarded as being in the colloidal 
state. Each of these groups of remedies has its own sphere of 
usefulness, and some of the synthetic drugs are more colloidal than 
is generally supposed (see section on Dyes in the 1917 B. A, Report 
on Colloids). In view, however, of the large amount of work which 
has been done by Ehrlich and others in the preparation. of synthetic 
compounds of arsenic and other metalloids it appears desirable to 
draw attention to the following facts :-— 
The action of synthetic compounds is usually due to their high 
molecular weight and often to the presence of ortho-amino groups. 
In some cases, a metal or metalloid is separated in colloidal sol 
form in the blood, the remainder of the drug merely serving as a 
vehicle. In others, the whole compound acts as a reducing or 
oxidizing agent. It may or may not be a coincidence that the most 
effective therapeutic reducing agents contain a metalloid (such as 
sulphur or iodine) whilst the most effective oxidizing agents contain 
a metal. 
In this connexion it is particularly interesting to compare the 
almost non-toxic colloidal metals and metalloids with that of the 
well known salvarsans and their compounds containing phosphorus 
(galyl), platinum, gold, copper or silver. According to Kolle*® the 
following doses are toxic to syphilitic rabbits; smaller doses are 
toxic to the human subject :— 
Towic Dose gris. Tolerated Dose grms, 
Salvarsan Ms re eee 0125 01 
Neo-Salvarsan ... ae ae 0°25 —0°3 0-2 
Hexamino-Salvarsan ... 403 — O15 
Galyl ea: os ss we 0°125 Or1 
Bismethyl-Standard ... noe 0°28 0°22 
Dichlorarsalyte ... : Sts O25 0-2 
Dibromarsalyte ... a ve 0°36 03 (2) 
Diiodarsalyte .... ens As — _— 
Copper Salvarsan K; ... ase O04 _ 0035 
Platinum Salvarsan ... a 0:07 0°05 
Gold Salvarsan ... ad a 0:03 0:02 
Silver Salvarsan ees se 03 0125 
29 Deutsche Med.-Wochenschr, 1918, 44,11 1 ,.11727 
ane 
ee 
