POLLTNOSIS 41 



products which cause it from a purely technical standpoint, in contrast 

 to that of tlie inimuno-cheniist, which dominates current literature. 

 The standpoint from which the problem has hitherto been approached 

 is that of the immunologist, who interprets the phenomena observed 

 in terms of toxins and antibodies, of protein-sensitization and ana- 

 phylaxis. The earliest notable work in this line is that of Dunbar 

 and Prausnitz. These workers made an elaborate investigation into 

 the toxicity of various kinds of pollen, using an extract of the pollen- 

 protein in very dilute solution of sodium chloride. The following is 

 a summary of the commoner plants in their list, which includes 

 25 Gramineae and 8 Cyperaceje, as well as numerous other forms. 



I. Grasses, as: — Phleum prafensc, Af/rostis alba, Poa pratcnsis^ 

 Anthoxantkum odoratum^ Dacfylis glomerata, iSecale cereale, Triti- 

 cum sativum^ Ayropyrum repens. 



II. Various plants, as : — -Rohinia Pseudacacia, Castanea dentata, 

 Acer ruhrmn, Chrysanthemum Leucanthemum, Bosa spp., Lonicera 

 Caprifolium, Ligustrum vulgare. (No indication is given as to 

 which of the latter plants are common causes of hay-fever and which 

 are merely rare instances.) 



The following plants which cause late hay-fever are mostly found 

 in the United States, namely : — Ambrosia trijida, A. artemisicefolia, 

 Solidago canadeyisis, S. nemoralis, Chrysanthemum sp., Dahlia, 

 Clematis virginiana. and Aster spp. 



In addition to these, the following grasses are given by Macdonald 

 as causing hay-fever in this country: — Poa pratensis, P. trivialis, 

 P. nemoralis, Arrhenatherum avenaceum, Lolium perenne, and 

 Alopecurus 'j^^'cde^isis. 



Prom personal experience, the following Gymnosperm pollens 

 were effective : — Abies concolor, Pimis excelsa, Pinus Pinsapo. 

 After prolonged exposure (40-50 minutes) to the pollen of Pinus 

 excelsa while harvesting it, slight symptoms were felt : i. e. irritation 

 of the eyes and nose^_|eeling of intense dryness in the posterior nasal 

 cavities. Later in the%same da}^ exposure for a few minutes to a 

 mixed hayfield {PhlrunVpratense being the j^rincipal grass in flower), 

 produced an acute attack, quite characteristic, with implication of the 

 bronchi and distinct rise of temperature. After this initial attack, 

 fresh exposure to Pinus-\>o\\en reproduced it with monotonous regu- 

 larity, after an " incubation period " of about 10 minutes. For the 

 succeeding four M^eeks every effort was made to avoid accidental 

 infection with grass or other pollen, and during the intervals between 

 the purposeful exposure to pollen of various kinds, the sjanptoms 

 were slight and in fact almost negligible. Each attempt at excitation 

 by direct insufflation of pollen was successful in producing an attack. 

 The pollen used principally was Pinus excelsa, owing to the ease with 

 which large quantities were obtainable. The susceptibility to Phleum 

 made laboratory experiments with grass-pollen almost impossible, 

 owing to the difficulties of harvesting. For an account of experi- 

 mental poUinosis in animals, see Ulrich, in the Journal of Immunology, 

 Nov. 1918. 



Unfortunately the lists previously given are not strictly comparable. 



