426 INFECTION AND IMMUNITY. 



pollen,, but it occurs also in pollens which do not 

 contain these granules. It may be extracted with 

 water or salt solution, is precipitated by alcohol, 

 resists the boiling temperature, and is of an al- 

 buminous nature. 



When the crude pollen reaches the conjunctiva, 

 s. nasa } or bronchial mucous membranes of suscep- 

 tible individuals, the toxin is dissolved out by the 

 secretions and absorbed by the lymphatics. When 

 applied to the conjunctiva it causes swelling, red- 

 ness and lachrymation. It is carried by the tears 

 to the nose and here causes excessive secretion, 

 swelling of the mucous membrane and sneezing. 

 It may become distributed systemically as a result 

 of absorption from the free surfaces and cause the 

 asthmatic attacks and general symptoms which are 

 seen in the intoxication. When injected subcuta- 

 neously into the arm both the asthmatic attacks 

 and coryza-like symptoms were produced. 

 Ant se?m Dunbar's antitoxic serum (pollantin)* is ob- 

 (Poiiantin). tained by immunizing horses with the toxin. It 

 seems to be of undoubted value in a certain per- 

 centage of cases, but fails unaccountably at times. 

 It is, perhaps, most effective when used in the 

 prodromal stage, the attacks being thereby pre- 

 vented. Its failure in certain instances may be 

 due in part to the inefficacy of the antitoxin 

 against the toxins of certain pollens. Again, in 

 certain individuals the affinity of the toxin for 

 the tissues may be unusually great so that a more 

 vigorous use of the remedy is demanded. 



Liibbart and Prausnitz published statistics of 

 285 cases, of which 65 were autumnal. In ordi- 

 nary hay-fever the serum gave positive results in 

 57 per cent., partially positive in 32 per cent, and 



