ON COLLOID CHEMISTRY AND ITS INDUSTRIAL APPLICATIONS. 167 
Colloidal copper is useful in the treatment of boils, though it is 
inferior to manganese for this purpose. In malignant diseases, the 
intra-muscular injection of copper has proved highly beneficial, the 
metal having been shown to be present in the growth within 24 
hours after injection. Copper is known to have a strong inhibitive 
_ action on low forms of life. Herschel, de Gres and others have 
_ stated that colloidal copper exerts an inhibiting action on all cell 
metabolism. In this connexion it is important to note that cases of 
_ cancer in which copper can be shown to be present in the growth 
are certainly the ones which are the most amenable to treatment. 
_ The difficulty lies in causing the copper to penetrate the periphery 
of the cancer. Pessaries of colloidal copper in glyco-geiatin have 
proved serviceable for uterine fibroids. 
_ Colloidal arsenic (0-2 7%) in doses of 2 ¢.c. has an extraordinary 
__ effect in pernicious anemia and herpes deformans. The simultaneous 
. presence of a liquid or colloidal protein appears to be essential to the 
_ proper reaction of arsenic. Thus, salvarsan per se has no action on the 
spirocheta pallida, which can move readily for some hours in a 
solution of salvarsan. Yet the introduction of a little serum or 
digested protein will cause their immediate death. The elimination 
_ of arsenic from the system is usually a matter of difficulty, but in 
the colloidal form its low toxicity combined with the small dosage 
reduce the risk of its retention to a minimum. 
Colloid palladium oxide has been applied successfully in the 
treatment of obesity by injecting it hypodermically into the fatty 
_ areas.”* 
Colloidal palladium sol has proved of value in gonorrhea. 
Colloidal nickel has been used in meningitis. 
lodine was discovered in 1811. In the form of an alcoholic solu- 
tion it soon became popular, but was afterwards neglected for many 
years. More recently, it has been brought prominently forward and 
©. 
at the present time* it is almost the only chemical antiseptic, except 
alcohol, employed by a large number of British surgeons. 
Colloidal iodine may be obtained in three forms: (i.) aqueous, 
Gi.) oil and (iii.) paste or ointment. The aqueous colloid (1 in 500) 
contains the element in its most active form, and is suitable for 
administration in all cases in which iodine or an iodide is indicated. 
lts action is more gradual than that of a solution of iodine, but more 
‘certain than that of iodides, and there is complete avoidance of 
“iodism” and nausea. '! he whole of the colloidal iodine is absorbed, 
hereas 85 per cent. or more of the ordinary iodides administered 
e excreted within 24 hours. 
When injected intravenously, the action of colloidal iodine is 
punity in cases of pyemia, and also to effect a softening of fibrous 
me, thus showing its absolute nontoxicity. Per se colloidal 
dine is only slightly parasitotropic and bacteriotropic, but micro- 
** M. Kauffman, Miinch. Mediz, Wochenschr, 525, 1913, 
4 Sir R. J. Godlee, Lord Lister (1917), 158. 
