PROCEEDINGS 
OF THE 
NATIONAL ACADEMY OF SCIENCES 
Volume 8 NOVEMBER 15. 1922 Number II 
BACTERICIDAL PROPERTIES OF THE PRODUCTS OF RADIUM 
■ EMANATION 
By John Albert MarshaIvL 
College of Dentistry, University of California 
Communicated, October 7, 1922 
The following abstract deals with a description of the use of radium 
therapy in periapical infections/ and supplements a preliminary note^ 
in which it was pointed out that solutions of the products of radium emana- 
tion possess distinct bactericidal properties. Additional data have been 
compiled but the analysis of them clearly indicates that with the present- 
day knowledge it is impossible to state definitely and conclusively why 
the products of the emanation produce such characteristic effects. 
Although it was reported in 1909^ that radium exerts an inhibitory 
influence on pathogenic and non-pathogenic organisms, no further work 
was done in this field until ten years later, when the former observations 
were confirmed.^ Bacteria of various types were exposed to radium 
emanation with the result that a distinct inhibitory effect upon the cultures 
was observed. 
In this present experiment a solution of the products of radium emana- 
tion is employed. The emanation tubes are usually discarded by the 
laboratories after they have undergone disintegration in respect to their 
content of gamma ray. However, they still contain in varying propor- 
tions radium A, B, C, and D. The effects which have been obtained 
are presumably not due to the hard gamma ray, but result in all probability 
from the action of the softer beta ray. 
The radioactive solution is prepared as follows: a "de-emanated" 
emanation tube is placed in a sterilized mortar of about 20-cc. capacity, 
covered with Ringer's solution and then crushed with a pestle. On ac- 
count of the rapidity with which the radio-activity of this solution dimin- 
ishes, it is advisable to crush the tubes immediately before use. This 
solution is carried directly to the infected area by means of sterile dressings. 
In the case of chronic or acute apical abscesses, found about the roots of 
