The Tucson citizen., 1902-04-15
HEAT AND DISEASE.
THE SUMS RAYS ARE FATAL TO MANY
SPECIES OF GERMS.
As a Disinfectant suhIight 10 the
Greatest Agent In Nature-Tem-
peratures mt which Disease Germs
Are Destroyed.

Sunlight fs fatal to some of the lower
forms OF living things, including GER
tain disease germs which are the cause
OF some Of the most fatal infectious
diseases that atfiIct the human race.
In fact, the greatest disinfectant in ma
ture is light, or, 10 be more exact, the
Tadiations Of the sun. including heat
rays, light rays and the invisible rays
at the violet end Of the solar spectrum.
An infectious disease Is one which
may be contracted by the introduction
Into the living body Of living disease
germs. which may be contained In diff
ferent kinds of infectious material.
Thus the disease germ (bacillus) which
produces diphtheria is contained in the
"exudate" or false membrane" de-
posted In the throat or nasal passages
OF those suffering from this disease,
and the material coughed up by pa
tient with diphtheria IL infectious ma
terinl. In cholera and in typhoid fever
the discharges from the bowels con-
tain the germ and are consequently In
fectious material.
Now. the object OF disinfection is to
prevent the extension of infectious dis
eases by destroying the specific infec-
tious agcnts-gerns- which give rise to
them; aud this In accomplished by the
use of dIsinfectants. Having, as nope,
made this clear.
Any chemical agent which destroys or
a hoA ndnR0 fxyU la, NJ
as dlsinfectant. and there are large
number of SO called "dlsinfeciants" in,
the market which are simply deodor-
ants and which are entirely untrust-
worthy for the destruction OF infectious
material-that is material containing
living disease germs.
These disease germs belong to the
class of low vegetable orga nisms--mi-
croscopIc plants~known as bacteria,
which as II rule thrive better in the
darkness than when exposed 10 day
hight. and some OF them are quickly
destroyed by exposure 10 direct sun
light In experiments made by me In
1893 1t was demonstrated that the chol-
era bacillus Is infaiiibly killed by ex-
posture 10 direct sunlight for an hour or
two. and the distinguished German
bActerioiogist. Dir. Robert Koch, has
shown that the bacillus Of consumption
tubercie baciIias~is destroyed by
similar exposure In a time varying
from = few minutes TO several hours,
depending upon the thickness OF the
layer OF material in which II 10 fna-
bedded.
As q result OF this 1t IL evident that
the material coughed up by patients
wtth consumption and containing tu-
bercte baeilli In vast numbers is far less
dangerous TO the community In regions
where the patient can live out of doors
and where the sun shines nearly every
day In the year.
Some disease germs which are not
killed outright by exposure TO the sun's
rays are greatly restrained in their de-
velopmept This 10 true OF the bacillus
OF typhoid fever. Although IL has been
shown by carefully conducted expert
ments that certain disease germs are
promptly destroyed By the luminous ra-
dla TONS from the sun, and especially
81 those at the Violet end OF the solar
spectrum. 1t IL also true that the heat
rays play an important part In the de.
struction Of harmful bacteria.
This In partly due to the fact that
certain disease germs are quickly de-
stroyed by being deprived of all mois-
ture-by desIccation. Thus the germs
OF cholera and Of pneumonia quickly
perish when completely dried.
Other germs. however, as those Of
typhoid lever. of diphtherIa and Of
consumption. may retain their vitality
in dried condition for several months.
But the germs OF all these diseases are
destroyed by comparatively low tenn
pcrature. In experiments which I
made several years ago l ascertained
that the germs OF pneumonia and Of
cholera were killed by exposure for a
few minutes to u temperature Of l2e
degrees +.
A still lower temperature Is effective
II the time OF exposure Is prolonged.
IL Is therefore evident that prolonged
exposure TO the direct rays of the sun
would destroy these germs independ-
emily OF the disinfecting power or
germicidal action OF the luminous rays
or the fatal results Of desiccation.
Other disease germs require high
er temperature for their destruction.
The typhoid bacillus and the bacillus
OF diphthcria are killed by exposure
to a temperature Of 40 degrees T. for
ten minutes. In general, IL may be
stated that this temperature Is fatal
to all the most important disease germs.
The facts stated furnish scientific
basis for practical disnfectlon. and 1t
is evident that when sunshine is avail
able no chemical agents are essential
for the destruction of disease germs.
ANY article of food or drink which has
been 1eated for a few minutes to some
thing near the boiling point of water
is absolutely safe, so fur as any dan
ger from disease germs is concerned.
and any article of clothing which has
been put through the ordinary opera
tions of the laundry is as safe as il 1t