Both Uses of

radiation
in
Arrowsmith

It was praised in Paris and Brussels and Cambridge as much as in New York, for its insight and for "the clarity and to perhaps be unscientifically enthusiastic, the sheer delight and style of its presentation," as Professor Berkeley Wurtz put it; which may be indicated by quoting the first paragraph of the paper: In a preliminary publication, I have reported a marked qualitative destructive effect of the radiations from radium emanations on Bacteriophage-anti-Shiga.†
Chpt 36

Furthermore, a quantitative relation is demonstrated to exist between this inactivation and the radiations that produce it.†
Chpt 36 *

Definitions:

(1) (radiation as in: nuclear radiation)
particles emitted by unstable atomic nuclei

Generally, radiation is discussed in terms of harmful levels of radiation that cause sickness. However, there is a normal level of radiation that is not harmful and sometimes radiation is carefully used for beneficial purposes such as medical treatments that use it to kill cancer cells.
(2) (radiation as in: electromagnetic radiation)
energy sent out as invisible rays such as from heat, light, or radio waves