528 THE PEPPER TREE AND HAY FEVER. 



After an interval of three or four days each snuft'ed up 

 about as much dried pollen as would he on a three-penny piece. 

 The result in both cases was an acute attack of hay fever, which 

 commenced after an interval of about six hours, and continued 

 iur between two or three days (48-72 hours). The dose snuffed 

 was probably excessive, but at this stage I was almost convinced 

 that there was no truth in the widely-held pepper-pollen-theory ; 

 and had the results been negative the experiment might reason- 

 ably have been regarded as giving the theory a knock-out blow. 



The way in which the pollen provoked the attack must now 

 be discussed. The pollen grains, being smooth, are not likely to 

 produce much mechanical irritation, and twO' medical practitioners 

 whom I consulted were of opinion that if the action of the 

 P'Qllen had been merely mechanical, the attack would not have 

 continued beyond about six hours. 



According to Dr. Scheppegrell the irritant action of wind- 

 borne pollen in causing hay fever is considered to be chemical, 

 and the substances absorbed are thought to be proteids, preceded 

 in the case of spiny pollen by a little mechanical irritation, 

 Indeed, the action of pollen extracts as a preventive measure is 

 based on an assumed chemical action of the pollen, the idea being 

 gradually, and without inconvenience to the patient, to accustom 

 his svstem to cope with these extractives. Professor W. P. 

 Dunbar, of Hamburg, who was one of the first to investigate the 

 relation of hay fever to pollen, found that the disease is caused 

 uj the pollen of certain grasses, rye, and other plants; and he 

 isolated from the pollen an albuminoid poison which when a'^nlied 

 to the nose of a susceptible individual causes an attack, while 

 there is no result in the case of a normal person. This proves 

 that the action of the pollen was chemical. Professor Dunbar* 

 was also able to show that the severity of the attack is directly 

 proportional to the amount of pollen in the air. 



For pollen to produce hay fever chemically a considerable 

 amount would be necessary ; and whilst in the experiment on 

 Professors Conlin and Rindl there was probably more than suffi- 

 cient inhaled to make this mode of action possible, this method 

 of producing the disease cannot be operative in the case of pepper 

 pollen under natural conditions, as the pollen is not normally 

 wind-borne. 



The artificial conditions under which the experiment was 

 performed should be kept in mind. The experiment merely 

 proves that pepper pollen can produce the disease ; but, though 

 capable of causing hay fever, it may never do so under natural 

 conditions. 



There remains a third possibility, viz : that pepper pollen 

 carries a bacterium, which growing on the mucous membranes 

 of the nose, produces the disease. On this assumption a single 

 infected pollen grain would be sufficient to inoculate a patient 

 and produce the disease. I am indebted to Dr. Targett Adams 

 for most willingly allowing the experienced 'Bacteriologist of the 



* Encycl. Britt.. nth ed. 



