Paper of Dr. D. Prince upon Atmospheric Purifica- 
tion in Relation to Infectious Diseases; Presented to 
the American Public Health Association. 
1886. AN EXPERIMENTAL STUDY 
IN RELATION TO THE 
Removal from the Air of the Dust or Particulate Material 
Supposed to Produce Yellow Fever, Small Pox 
and other Infectious Diseases. 
The study of the subject in relation to the purification of the air from 
the particulate material causing, in wounds, putrefaction, erysipelas and 
hospital gangrene, has led to further thought in relation to general infec- 
tious diseases. 
The study of a subject for a special application of principles, often 
opens up to the mind the practicability of arranging the details of methods 
so as to accomplish other objects than those contemplated in the first 
endeavor. 
The writer of this paper has been for two years making an experi- 
mental study of expedients for securing a dustless atmosphere for surgical 
purposes. It is now generally believed that one of the most important 
causes of the bad behavior of wounds is the prevalence in the air of float- 
ing particulate material, the exclusion of which from wounds is important. 
After the discovery of oxygen there came a theory that the decompo- 
sition of exudations from wounds and abraded surfaces attended by foul 
odors and evidently poisoning the system, was owing to the contact of 
oxygen. 
The history of surgery includes the account of many expedients for 
excluding oxygen upon the supposition that the difference in the behavior 
of subcutaneous injuries from that of open wounds was to be accounted 
for by the presence of this or some other gas. 4 
It is not until recently that it has been established beyond dispute, 
that the infection which is chiefly dreaded is not gaseous, hut particulate 
and capable of being separated from the air in which it floats. 
The problem has been to open the abdomen or other part and to keep 
it open for an hour, if necessary, and on closing it again, to have it in 
such a condition, as to material floating in the air, as it would be in if all 
the proceedings had been carried on subcutaneously. 
The attempt to reach this desideratum by water filtration has been 
successful as to those atmospheric agents occasioning putrefaction. It 
has been found, however, that the germs of mould get through the showers 
of water to a limited extent. They are the lightest of germs, and develop 
most abundantly in wet weather and in damp places. The plan by water 
has been—first, to moisten the air by steam; to carry it next through a 
shower of water; to heat it by a stove (except in hot weather) and then to 
carry it through another spray of water. 
The first thought was to secure a purified atmosphere for an operating 
room, but in the progress of experiment and reflection, the plan was im- 
proved so as to secure a current of air thus treated, to envelope the wound 
itself, so that impurities escaping from the occupants of the room could 
not come in contact with the wound; being blown away by the blast of 
pure air. 
Finding that air cannot be completely deprived of its floating material 
by water, attention has been given to the devising of a practicable plan 
for purification by the passage of air through cotton. The capability of 
cotton of arresting all particulate material floating in the air is a remark- 
able discovery. Most interesting details of experiments to prove the 
power of cotton in arresting the agents of putrefaction changes may be 
found in the Popular Science Monthly for February, 1878, page 476, and 
March, 1878, page 501, in which the observations of Professor Tindall 
upon this subject are related. The fact that a seal of cotton pre- 
serves any kind of material from decomposition, provided that the 
agents of decomposition are not already in it, shows—first, that these 
agents are not gases; for anything of a gaseous nature goes readily 
through cotton; and, next, this fact shows that gases do not initiate decom- 
position and that particulate material does. This proposition has been so 
thoroughly worked out by experiment and observation that it is not worth 5 
while to go over the proofs. The work of experimentation with culture 
liquids is greatly facilitated by this knowledge. The experimenter has 
only to put a plug of sterilized cotton into the mouth of a test tube con- 
taining the liquid under observation, and to subject this liquid to daily 
boiling for a few times, in order to be sure that it is free from organisms, 
and he has a liquid under circumstances to keep free from decomposition 
for an indefinite period. 
On the introduction of any infectious material to be experimented 
upon, he is equally free from the annoyance of the introduction of any 
atmospheric agent, unless the intrusion takes place at the time of opening 
the cotton seal. 
This is readily seen to be much more convenient of management than 
flasks hermetically sealed. The same tubes can be used over and over to 
aDy extent. The problem for perpetuating the sterilization of stationary 
or still air, is thus completely worked out. The arrangement for an apart- 
ment of many feet in dimensions, is as simple as that for a test tube. 
The problem now in hand, however, is to secure the sterilization of 
air in motion and which can have no boundary wall between it and the 
ordinary atmosphere. 
The use to be made of such air is (1st) to secure to a surface freedom 
from the influence of septic or pathogenic agencies, at the same time that 
it is being manipulated for surgical or other purposes; and (2d) to secure 
for living beings an air to breathe, free from infectious agencies; or to 
take immediately away, the products of exhalation from the lungs and 
other parts of the body. 
A portion of fruit may be sealed in a can by cotton or by solder, and 
it will keep indefinitely, but a breathing animal, to be free from septic or 
pathogenic agencies, when these agencies are round about him, must have 
some other anangement, by which his own exhalations maybe carried 
away. 
If it is intended, in a particular case, to shield a person from the infec- 
tion of yellow fever in an infected location, the filtration of the air to 
arrest the particulate material of the infection, must permit a perpetual 
change. This is secured in a great degree by respirators, worn upon the 
face, which are usually made to sterilize the entering air and perhaps 
might be made to sterilize the air of expiration. 6 
To prevent a subject from taking a disease, the filtration of the inspired 
air is required, and to prevent his imparting a disease, the filtration of the 
air expired must be secured. 
The endeavor, at present on hand, is to secure an arrangement which 
may take a company of men in an ordinary room and do for them what 
the respirator is supposed to do for one man. The suction by the expan- 
sion of the chest is a force capable of drawing a sufficient quantity of air 
through the cotton in front of the lips and the nose; but for the face, res- 
pirator, the problem of sterilizing the expired air, has not been worked 
out, because it would be extremely inconvenient to blow with sufficient 
force, during each expiration, to propel the expired air through a cotton 
sterilizer. On a large scale, however, the difficulty vanishes, because it is 
as easy for a fan to push as to pull. 
The device on the one hand for blowing the fire of a furnace, and on 
the other hand for sucking away the sawdust of a circular saw in a plain- 
ing mill, is the finger point toward the arrangement needed. This is an 
instance in which inventions for particular purposes, become equally 
valuable for far different ends. In any establishment in which there is an 
engine, or a motor of any kind, the remainder of the detail may be easily 
worked out. 
The problem is not difficult, if the air is to be stationary, but the cir- 
cumstances require that a considerable quantity of air shall be supplied 
and be quickly replaced by another supply, in order that the impurities, 
generated may be carried away. All know the effect of a hedge or a strip 
of forest in arresting the force of the wind in the winter, when there are 
no leaves, but only the filter of limbs. 
What these limbs are to the wind, a layer of cotton is to the current 
of air employed for the purposes referred to. As it is important for sur- 
gical purposes that the sterilized air should have a temperature equal oO 
that of the body, while it is comfortable to have the general air of the 
room much lower in temperature, there arises the difficulty of the ten- 
dency of the warm air to rise to the upper part of the room, instead of 
enveloping the wound of a patient under operation or surrounding a sick 
man lying upon a couch. It is entirely practicable to secure a sufficient 
degree of motion by means of heat if there is not the impeding effect of 
the cotton. To overcome this difficulty, the force of a fan is employed which is 
run by an engine. By establishing a hurricane on one side of the cotton, 
a moderate wind is secured on the other, having a force sufficient to over- 
come the effect of light specific gravity in the warm sterilized air. For 
surgical purposes, the addition of a small amount of steam is desirable, in 
order not to dry the exposed moist surfaces, and an arrangement for that 
purpose is seen in the drawing. 
This figure represents a scheme for sterilizing the air which enters a 
room for protection against infection, and one for sterilizing the air escap- 
ing from a patient who is supposed to be afflicted with small pox or 
some other infectious disease. >•- 8 
In this scheme the particulate material is supposed to be arrested by 
the cotton, which, at the end of the necessary period, can be burned. 
The arrangement is in the form of a chest of drawers, the outside of 
the chest being a cube of fifty inches. 
There are three drawers, each having an area of cotton 40x40 inches ; 
equal to 1,600 square inches; the area of the three being 4,800 square 
inches. 
There are two air tight floors; one below the upper shelf and one 
below the middle shelf. 
The air enters above each shelf of cotton, and escapes below it. A 
sheet of woven wire with three-quarter inch openings serves as the support 
for the cotton, which is about an inch in perpendicular thickness. 
For blowing sterilized air into a room, the blower must push. For 
taking foul air out of a room, the blower must pull. 
The arrows show every where the course of the current of air. 
Observations are in progress to prove the approximation to perfection, 
of this device for depriving the air of the material in it, which is capable 
of starting and perpetuating changes in organic, substances. 
The value of an expedient like this on ship board must be obvious a>, 
first sight. The patient being confined in an appartment, an arrangement 
may be made to be run by the machinery of the ship, to give him pure air 
or to purify the air which is poisoned by emanations from him, or both 
combined. 
An experiment to determine the penetrability of cotton by gases while 
the particulate material is arrested has been made by burning sulphur in 
the air previous to its passage through the cotton and finding that the 
sulphur dioxide passes readily through, while the particles which ordinarily 
give a blue tinge to the sulphurized air, have been arrested in the cotton 
mesh, leaving the air perfectly transparent.