94 Report of Schimmel 8j Co. April/October 1917. 



Germany, the hay-fever season begins in the second half of May; a little sooner, in 

 southern Germany. The climax of the suffering coincides with the blooming of the 

 grasses, especially of rye. 



In the United States of North America, hay-fever occurs as "spring fever", but 

 rather seldom in comparison with the so-called "fall fever", beginning early in September 

 with similar symptoms and lasting for about 6 weeks. Hay-fever occurs chiefly in 

 Germany, England and the United States, but is also found in other countries. Above 

 all the higher civilized people, especially brain-workers, are attacked, and, it is said, 

 men more frequently than women. 



There has been no lack of attempts to explain the external cause of hay-fever; 

 Elliotson was the first to ascribe it to pollen. Blackley gave this theory the first solid 

 foundation by his investigations, as he proved that only during the hay-fever season 

 there were considerable quantities of pollen in the air and that such pollen, obtained 

 in a pure state, had the property of causing the typical symptoms on coming into 

 contact with the mucous membranes of the nose or mouth of hay-fever patients. 

 According to Blackley's view, any pollen was capable of causing hay-fever. 



However, Blackley's observations, which for several years had been considered 

 as authoritative, were not left uncontradicted. Under the influence of the first successes 

 of bacteriology, one thought it necessary to consider hay-fever as an infectious illness. 

 All sorts of bacteria were described as causing hay-fever. On the other hand, it was 

 tried to prove that the exhalations of plants, aromatics and essential oils, such as are 

 developed under the influence of sunshine during the first time of flowering, were 

 responsible for the attacks of hay-fever. 



It was reserved to Dunbar's investigations and to those of his collaborators Prausnitz, 

 Kammann, and Liefmann, to make Blackley's old pollen theory valid again and to put 

 it on a scientifically indisputable footing. Dunbar obtained pollen in a pure state by 

 cutting grasses, or the ears thereof, shortly before flowering, placing them in water in 

 a warm spot and making the pollen drop on glossy black paper by repeated rapping 

 at the stalks. 



Infinitesimal quantities of this grass pollen were then introduced into the con- 

 junctival sack or into the nostrils of hay-fever patients by means of a sterile piece 

 of cotton wool. With all of them, the typical symptoms of hay-fever appeared within 

 a very short time, although nearly all the experiments were carried out in times when 

 there is no hay-fever. Persons who do not suffer from hay-fever, however, were not 

 at all influenced by this treatment. Furthermore, a small quantity of rye pollen was 

 diffused in a cupboard where there were a hay-fever patient and a normal person; whereas 

 the latter was not influenced in the slightest degree, the former felt the characteristic 

 troubles already after a few minutes. The corresponding symptoms of irritation 

 occurred with a hay-fever patient also when rye pollen was introduced into the anus, 

 a proof that hay-fever is not due to a special sensitiveness of the trigeminus, as had 

 formerly often been supposed. 



So far, the experiments had only shown that the pollen of gramineae may be looked 

 upon as the cause of hay-fever, — the question was still open whether other kinds 

 of pollen would act in a similar way and whether the quantity of pollen present in 

 the air under normal conditions would suffice to bring about attacks of hay-fever. 

 Dunbar and Liibbert's investigations, continued through several years and which com- 

 prised the examination of grasses and 106 other plants, showed that, in addition to 

 the pollen of 33 graminea? and cyperacese, only the pollen of honeysuckle (Lonicera 

 caprifolium), lily of the valley (Convdllaria majalis), Polygonatum multiflorum, common 



