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Experimental evidence on the point referred to is shown by the following: 20 grams of commercial canned corn and string beans previously autoclaved in open petri dishes for 30 minutes at 17 pounds' pressure were added to 100 c. c. flasks of beef heart media, together with 1 gram of virgin soil from the ranch, heated to 80° C. for one hour, and overlaid with sterile vaseline. In all, 18 cultures so treated were incubated at 37° C. for 10 days. Two flasks containing soil but no vegetables served as controls. Tests for the presence of toxin and the determination of type were made by intraperitoneal inoculation into mice.
The results are shown in the following table:
It will be seen that of two specimens of virgin soil alone in 1 gram amounts, one produced a toxin, type B, B. botulinus. This same soil in 1 gram amounts (eight specimens) with the addition of autoclaved corn yielded 4 positives, type A. With the addition of beans, out of 8 specimens tested, 3 were positive. Two of these proved to contain type A and one type B toxin, B. botulinus.
Obviously the soil contains both types. The results obtained when the soil alone is planted in ordinary beef-heart medium indicate that type B is predominant. When the soil, together with the corn or beans, is planted in the same medium, type A appears to predominate, indicating that the corn and beans have an enriching effect or favor the growth of type A. There is the other possibility that type B, being the less resistant type to heat, may be destroyed, although this is unlikely to have occurred in the above experiment, as all temperatures were the same, namely, 80° C., one hour.
The following experiment seems to prove that both types, A and B. were present in the soil. Some of the original cultures obtained by planting the soil in the beef-heart medium, which gave a positive test for the presence of type B toxin by the mouse test, were boiled for 30 minutes. Agar shake cultures were made from these and incubated. From these shake cultures, 37 colonies morphologically resembling those of B. botulinus were fished with pasteur pipettes under the dissecting microscope and placed in beef-heart enrichment media. Ten of these, after 10 days incubation at 37° C., when
tested, were positive for type A toxin. No type B colonies were isolated. There is, of course, the possibility that the liver agar may have, supplied something that favors the growth of type A; or that in the process of boiling, type B organisms were destroyed; or that the writer unintentionally "fished” type A colonies only and missed those of type B.
To test further the effect of heat, the original soil samples in beefheart media, 12 in number, were detoxified by heating to 80° C. for one hour. Twenty grams of autoclaved corn were added to each of two flasks, and 20 grams of autoclaved beans to each of two other flasks. These flasks were then boiled for 30 minutes and incubated at 37° C. for 10 days. Four flasks similarly treated were not boiled. Two flasks without corn or beans were used as controls for each treatment, with and without boiling. The results are briefly shown in Table IV.
TABLE IV.—Experiments to determine the effect of boiling on the types of organisms.
The above experiment does not offer any great amount of additional evidence as to the effect of temperature on types, but indicates rather definitely that with the addition of corn and beans type A toxin was produced in three out of eight instances in soil in which previously type B had been demonstrated.
It has been stated that type A colonies were fished from liver agar shake cultures made from the growth, in beef-heart medium, obtained from the soil which apparently contained only type B organisms. It was thought that by the addition of soil to beef-broth cultures of these type A colonies it might be possible to demonstrate type B toxin. One gram of the original soil was therefore added to four of these cultures. Two cultures without the addition of soil served as controls. All the cultures were subjected to a temperature of 80° C.
for one hour and were then incubated 10 days. Tests for toxin production showed type A in all the cultures.
4 cultures from liver agar“shake" colonies which yielded type A originally, | All proved positive type A plus 1 gram original soil, heated to Soo C., 1 hour.
toxin. Conto.- 2 caltures from liver agar shake" colonies which yielded type A Both cultures proved posi&iginally, heated to 0° C., 1 hour.
tive type A toxin.
These results indicate the stability of the type A, once the toxin is formed in the food, even when there is the addition of soil in which type B toxin can generally be demonstrated. However, it would seem more probable that there were many more type A spores in the culture than there were type B spores in the soil and that type A developed and type B was suppressed.
The above experiments are offered as evidence that probably many soils contain spores of both type A and type B, B. botulinus, which, when inoculated into suitable media, are capable of producing their selective type of poison. (The conditions that induce the formation of specific types in preserved foods are far from being clearly understood.) It is, however, not unlikely that foods like corn and string beans, when contaminated with soil containing the spores of both type A and type B, B. botulinus, are responsible in some manner for the production of one or the other type of toxin, and these experiments suggest a more frequent occurrence of type A toxin. We have observed on this ranch curious and interesting anomalous data. Furthermore, the data render doubtful any dogmatic assertion as to any particular type of toxemia being limited to foods grown in any particular geographical region. The experimental and field data here presented do not furnish any conclusive evidence that one type is a mutant of the other, but rather surprisingly indicate that type B is the predominating type in both garden and virgin soil of this restricted area of a western State. Likewise, it is conclusive that this Tanch has had a remarkable concentration of outbreaks and that home canning of vegetables grown on its soil under the present conditions is unsafe.
Acknowledgments. It is desired to acknowledge with thanks the Cooperation of Dr. Paul West, county health officer of Okanogan County, Wash.
PHYSIOLOGICAL EFFECTS OF HIGH TEMPERATURES AND
HUMIDITIES WITH AND WITHOUT AIR MOVEMENT.
Effects on Body Temperature and Pulse Rate of Subjects at Rest.
By R. R. SAYERS, Surgeon, United States Public Health Service, Chief Surgeon, Bureau of Mines, Depart
ment of the Interior; and D. HARRINGTON, Supervising Mining Engineer, Bureau of Mines, Department of the Interior.
For several years the writers have been studying various problems of the effect of air conditions in metal mines upon underground workers. In 1918 a short study was made in certain hot and deep mines, and brief reports were published in the Engineering and Mining Journal (August, 1920) and in the Public Health Reports (vol. 36, No. 4, January 28, 1921).'
In 1921 a more extended study was made (also in hot and deep metal mines) for the purpose of ascertaining the limiting conditions imposed upon underground workers by the physiological effect of various air movements, temperatures, and humidities. The determinations were made both with the subjects at work and at rest. It is intended to report this later investigation in a series of short papers, each paper to consider one particular phase of the work. The present paper deals with the effect on body temperature and pulse rate of subjects in still air as compared with moving air, at temperatures from 90° to 100° F., and of 100 per cent relative humidity, the subjects at rest.
SUBJECTS USED IN THE INVESTIGATION,
In order to avoid the criticism that data taken upon investigators working in mines only intermittently would not be representative of results taken on everyday mine workers, there were used in the 1921 study, in addition to one of the previous investigators, two miners, one having just left employment as general mine laborer in some of the worst places in one of the hottest mines in the district, and the other having been employed in various capacities in the mines in which the experimental work was being conducted. These three subjects, who were the reagents supplying most of the data, were vigorous and in good health, and thoroughly accustomed to mining work in hot, humid air. All of them remained in good physical condition throughout the period of making the tests. In addition, during the underground field work, data were taken on various other underground employees of the mines entered.
? A preliminary study of the physiological effects of high temperatures and high humidities in metal mines, Public Health Reports, vol. 36, No. 4, Jan. 28, 1921, pp. 116-129. Reprint No. 639.
Blood pressure (taken with a Tycos sphygmomanometer), pulse rate, and rectal body temperature, together with any symptoms of dizziness, headache, weakness, perspiration, etc., were recorded. The air temperature and humidity were taken by a sling psychrometer, and the air velocities by an anemometer. The exact time of taking the readings was also noted. One of the investigators acted as recorder of all the data taken.
The outside, or surface, air temperature and humidity were usually observed before going underground, and the air temperature, body temperature, pulse rate, and blood pressure were taken in the washhouse or "dry" just before going underground. After going underground and before entering the place chosen for the test, a full set of readings was made in a near-by place where it was quiet enough to use the blood pressure apparatus. Such data were also taken in the test place, when feasible.
Incident to taking the physiological data on the subjects, Doctor Sayers necessarily participated in the stay in the hot places and, therefore, was able not only to observe the effect of conditions on the subjects, but also to experience the symptoms himself. Engineering data, such as psychrometric, barometric, and anemometric readings, were made by Mr. Harrington, who also acted as one of the subjects throughout the investigation.
The subjects sat still in the hot or test places, and during the test period exerted no physical effort other than the small amount involved in taking readings of blood pressure, pulse rate, body temperature, psychrometric data, etc. Often it was found necessary to omit taking blood pressure and pulse in the actual test place, in which cases this was done just before entering and just after leaving the test place. In a few instances the data obtained during the test were greatly influenced by a very slight amount of work done by a subject just before beginning the test.
In practically all of the above experimental work samples of the air were taken, the analyses of which showed nearly normal air as far as carbon dioxide and oxygen were concerned, and no carbon monoxide or other poisonous gases were found. The air in the place where the tests at 95° F. or over were made was as nearly absolutely saturated as can be obtained underground, and psychrometric readings were taken frequently enough to make certain that any changes occurring during the test would be discovered.
Figure 1 shows the effect on the body temperature of one subject (No. 5) of still air at 95°, 96°, and 100° F., and of moving air at 911°, 950, 981°, and 100° F. The effect of these various air temperatures is shown on the graph by using zero to represent the subject's tem