COMPOSITAE — THISTLE FAMILY — RAGWEED 767 



tioublesome as an exciting cause with reference to hay fever. The following 

 from Dr. Johnson on this point is of interest : 



These plants are said to be stimulant, tonic, and astringent. A decoction has been used, 

 chiefly in domestic practice, as a topical astringent in chronic catarrhal affections. 



Of late years A. artemisiifolia has attracted considerable attention on account of its real 

 or assumed agency in the production of hay-fever. The plant produces pollen in great 

 abundance, which is extremely irritating to the air-passages of many people, and is capable of 

 exciting asthmatic attacks in susceptible persons. Now as the weed is so very abundant, and 

 its time of flowering coincident with the greatest development of hay-fever, the relation of 

 cause and effect has been asserted by many writers. That it may be so in a certain proportion 

 of cases is quite probable, but that its influence in this direction has been overrated is still 

 more probable. The pollen of all plants is irritating to the air-passages of sensitive people, 

 but probably little more so than any other dust of an organic character; and the proportion 

 which rag-weed pollen in the air of any specified locality bears to that of all other plants com- 

 bined must be very small indeed. Much less still must its proportion be to other pollen and 

 organic dust in the air of cities, where this affection has become endemic — and fashionable.. 



The ragweeds, marsh elder, goldenrod, and chrysanthemum, as well as the 

 pollen of some grasses, are said to produce hay fever. In recent years a 

 toxic substance has been isolated which belongs to a class of poisonous sub- 

 stances known as toxalbumin. 



The fact that this troublesome disease is caused by a poisonous toxin has 

 led to a study of serum treatment by Dunbar* who has produced an antitoxin 

 which he calls "pollantin," and Weichardt** another called "graminol." Pol- 

 lantin is obtained from *lie blood serum of horses which have been immunized 

 with the pollen toxin. I -anbar's hay fever serum is sold both as a powder and 

 as a fluid. There are toose, however, who believe that hay fever is not due to 

 poison by pollen toxin so that this treatment can be of no use. A. Wolff- 

 eisner*** attributes the action of the serum not to antitoxins but to colloidal 

 substances. Weichardt prepared the serum from the blood of herbiverous 

 animals. Sattistics of The Hay Fever Union of Germany for 1906 indicate 

 that the results with the treatment of "graminol" were favorable. 



A correspondent from Nebraska sent to the writer a specimen of the small 

 ragweed stating that it was abundant in his pasture and that where cattle used 

 it as forage, the mouths of these animals became very sore. The plant is bitter 

 and possibly may be irritating at times. There were no parasitic fungi on the 

 specimens sent us. 



7. XantJihun (Tourn.) L. Cocklebur. Clotbur 

 Coarse low branching annual herbs with alternate toothed or lobed petioled 

 leaves; monoecious flowers; staminate flowers with a short involucre of several 

 distinct bracts, receptacle cylindrical ; pistillate flowers with a closed involucre, 

 covered with hooked prickles: 2-celled, 2-flowered, in fruit forming a bur; 

 achenes oblong, flat, without pappus. 



The 12 species are widely distributed. 



X a lit Ilium splnosum L. Clotbur 

 A pubescent branched annual herb with slender yellow 3-parted spines in 

 the axils; leaves lanceolate or ovate lanceolate, white downy underneath; bur 

 oblong cylindrical, armed with single short beak and numerous glabrous prickles. 



* Deutsch Med. Woch. 1903:140. 



Berlin Klin. Woch. 1903:24, 25, 26, 28. 



** Klinisch-ther. Woch. 1903:1457. 



*** Das heufieber, sein wesen und seine Behandlung. Miinchen 1906. In this connection 

 the very excellent review on Serum Therapy in E. Merk's Annual Report, 1909, Vol. 23 

 should be consulted. 



