Abstract

For many years it has been known to Toledo physicians that an "asthma colony" existed in a certain district of East Toledo. Suspicion had long pointed to a linseed oil mill as being the cause of the trouble, for many of these asthmatic patients asserted that their attacks coincided with the odor of linseed oil from the mill when the wind was in the right direction. Complaints had been made at various times to the city health department, but nothing incriminating the oil mill could be found. The state department of health also made an investigation, but did not learn anything of value concerning the unusual number of asthma sufferers in this vicinity. Early in 1927, one of us was appointed health commissioner for the city of Toledo. One of the first problems presented was the demand from residents of this district that something be done to prove or disprove the connection of this oil mill with the asthma situation. On investigation, it was found that the oil mill not only manufactures linseed oil but also expresses castor oil from castor beans. After all the oil is removed from the beans, the resulting cake is finely ground to form what is known in the trade as castor bean "pomace." This pomace is sacked and sold as an ingredient of fertilizer, being valuable for this purpose because of its high nitrogen content. Most of the castor bean residue is recovered and sacked during the process of grinding the "cake" after the oil has been pressed out, but there is a considerable amount of fine dust which does not fall through the screen of the grinding-mill. This dust is blown out into the air through three good sized pipes projecting through the roof of the mill, and at all times when the mill is in operation a fine cloud of this dust can be seen issuing from these pipes. The dust is so fine that it will pass through a 200 mesh wire screen; from this it is apparent how readily it can be carried by the wind. Previous efforts to solve the relation of this oil mill to the asthma situation centered on linseed oil, because the sufferers had always noted the odor of linseed oil when the wind was in the right direction. However, we found that after the oil was expressed from the flaxseed there still remained about 9 per cent of oil in the flaxseed, making it too heavy to be wind-borne. Furthermore, there was no flax dust blown into the air on the linseed oil side of the mill. Our attention, then, was devoted to a study of the castor bean dust as being the possible cause of these numerous cases of asthma. No doubt the reason it was previously overlooked is that this castor bean dust is almost odorless as compared with linseed oil. The asthmatic sufferers and their families could easily smell the linseed oil fumes but were not aware of the invisible castor bean dust particles in the air.

Across the street from this oil mill is located the Oakdale School. For some time the chief topic discussed at the Parent-Teachers Association meetings at this school had been this asthma problem. Several of the pupils had lost time from school because of asthmatic attacks coming on in school, and many of the parents were also affected for days at a time. The president of this association gave us a list of eighty-five names and addresses of persons living in this vicinity who ascribed their asthmatic attacks to the presence of this oil mill. These persons were asked to report to the office of the city health commissioner, and there the
examinations were made.

Of these eighty-five persons, we have had the opportunity of examining thirty-two. Two of these proved to have cases of seasonal hay-fever with pollen asthma, so that there were actually thirty patients seen who had asthma at all times of the year. The histories these patients gave were all quite similar. They all had lived within a mile of the plant and had no asthma before moving to this district, and the onset of the attacks
varied from one to seventeen years after moving to this neighborhood. The attacks were nocturnal in the men who worked during the day at a distance from their homes, but occurred day or night in the housewives and children whose work did not take them away from the vicinity. Attacks were most frequent and most severe during the fall and spring months when the wind
attained its highest velocity, and these patients invariably had attacks when the wind blew toward their homes from the direction of the mill. Thus, patients on the south side of the mill would have asthma when the wind was from the north, while those living on the north side would be free from attacks at this time. When the wind shifted to some other direction, conditions would be reversed. The mill is in operation day and night. The mill is in operation day and night but closed June-August when symptoms improved. The histories also showed that many of these patients found that they could obtain relief by leaving the neighborhood but that the asthma recurred when they returned to their homes ; if they went on vacations
or moved away from the mile radius of the mill, their asthmatic attacks disappeared.

The thirty patients seen were all tested cutaneously by the scratch method with 1: 100 extracts of castor bean dust and flaxseed dust made up with Coca's solution. At first we used the raw dust moistened with tenth-normal sodium hydroxide, but we soon found that extracts of the dusts were more convenient and were just as reliable for testing. Every one of these
thirty patients gave positive reactions to the castor bean extract, and the wheals for the most part were remarkable for their size. We designated the reactions ++++ when the wheal measured 2.5 cm. in diameter, but some
of the wheals attained a diameter of from 6 to 8 cm., and the pseudopodia extended outward several more centimeters. Only two cases exhibited a cutaneous reaction of less than 2.5 cm. Some of these reactions were delayed for a period of from one-half to four hours but they invariably appeared.

We were well aware that castor bean dust contains a very irritating substance, ricin, so we made control skin tests on about forty persons, all with negative results. Many of these control patients belonged in the hyper-
sensitive class as they were subject to hay-fever, asthma and perennial hay-fever. It would appear then that the positive reactions that we obtained in the cases of castor bean dust asthma were specific reactions and not due to the irritating effect of ricin in the extract.



Plain text: For many years it has been known to Toledo physicians that an "asthma colony" existed in a certain district of East Toledo. Suspicion had long pointed to a linseed oil mill as being the cause of the trouble, for many of these asthmatic patients asserted that their attacks coincided with the odor of linseed oil from the mill when the wind was in the right direction. Complaints had been made at various times to the city health department, but nothing incriminating the oil mill could be found. The state department of health also made an investigation, but did not learn anything of value concerning the unusual number of asthma sufferers in this vicinity. Early in 1927, one of us was appointed health commissioner for the city of Toledo. One of the first problems presented was the demand from residents of this district that something be done to prove or disprove the connection of this oil mill with the asthma situation. On investigation, it was found that the oil mill not only manufactures linseed oil but also expresses castor oil from castor beans. After all the oil is removed from the beans, the resulting cake is finely ground to form what is known in the trade as castor bean "pomace." This pomace is sacked and sold as an ingredient of fertilizer, being valuable for this purpose because of its high nitrogen content. Most of the castor bean residue is recovered and sacked during the process of grinding the "cake" after the oil has been pressed out, but there is a considerable amount of fine dust which does not fall through the screen of the grinding-mill. This dust is blown out into the air through three good sized pipes projecting through the roof of the mill, and at all times when the mill is in operation a fine cloud of this dust can be seen issuing from these pipes. The dust is so fine that it will pass through a 200 mesh wire screen; from this it is apparent how readily it can be carried by the wind. Previous efforts to solve the relation of this oil mill to the asthma situation centered on linseed oil, because the sufferers had always noted the odor of linseed oil when the wind was in the right direction. However, we found that after the oil was expressed from the flaxseed there still remained about 9 per cent of oil in the flaxseed, making it too heavy to be wind-borne. Furthermore, there was no flax dust blown into the air on the linseed oil side of the mill. Our attention, then, was devoted to a study of the castor bean dust as being the possible cause of these numerous cases of asthma. No doubt the reason it was previously overlooked is that this castor bean dust is almost odorless as compared with linseed oil. The asthmatic sufferers and their families could easily smell the linseed oil fumes but were not aware of the invisible castor bean dust particles in the air. Across the street from this oil mill is located the Oakdale School. For some time the chief topic discussed at the Parent-Teachers Association meetings at this school had been this asthma problem. Several of the pupils had lost time from school because of asthmatic attacks coming on in school, and many of the parents were also affected for days at a time. The president of this association gave us a list of eighty-five names and addresses of persons living in this vicinity who ascribed their asthmatic attacks to the presence of this oil mill. These persons were asked to report to the office of the city health commissioner, and there the examinations were made. Of these eighty-five persons, we have had the opportunity of examining thirty-two. Two of these proved to have cases of seasonal hay-fever with pollen asthma, so that there were actually thirty patients seen who had asthma at all times of the year. The histories these patients gave were all quite similar. They all had lived within a mile of the plant and had no asthma before moving to this district, and the onset of the attacks varied from one to seventeen years after moving to this neighborhood. The attacks were nocturnal in the men who worked during the day at a distance from their homes, but occurred day or night in the housewives and children whose work did not take them away from the vicinity. Attacks were most frequent and most severe during the fall and spring months when the wind attained its highest velocity, and these patients invariably had attacks when the wind blew toward their homes from the direction of the mill. Thus, patients on the south side of the mill would have asthma when the wind was from the north, while those living on the north side would be free from attacks at this time. When the wind shifted to some other direction, conditions would be reversed. The mill is in operation day and night. The mill is in operation day and night but closed June-August when symptoms improved. The histories also showed that many of these patients found that they could obtain relief by leaving the neighborhood but that the asthma recurred when they returned to their homes ; if they went on vacations or moved away from the mile radius of the mill, their asthmatic attacks disappeared. The thirty patients seen were all tested cutaneously by the scratch method with 1: 100 extracts of castor bean dust and flaxseed dust made up with Coca's solution. At first we used the raw dust moistened with tenth-normal sodium hydroxide, but we soon found that extracts of the dusts were more convenient and were just as reliable for testing. Every one of these thirty patients gave positive reactions to the castor bean extract, and the wheals for the most part were remarkable for their size. We designated the reactions ++++ when the wheal measured 2.5 cm. in diameter, but some of the wheals attained a diameter of from 6 to 8 cm., and the pseudopodia extended outward several more centimeters. Only two cases exhibited a cutaneous reaction of less than 2.5 cm. Some of these reactions were delayed for a period of from one-half to four hours but they invariably appeared. We were well aware that castor bean dust contains a very irritating substance, ricin, so we made control skin tests on about forty persons, all with negative results. Many of these control patients belonged in the hyper- sensitive class as they were subject to hay-fever, asthma and perennial hay-fever. It would appear then that the positive reactions that we obtained in the cases of castor bean dust asthma were specific reactions and not due to the irritating effect of ricin in the extract.

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