72 



Scientific Proceedings (52). 



in brackets indicate the number of units required to produce an 

 itching sensation in the eye which apparently runs considerably 

 higher than the flushing point in highly immunized individuals. 

 Extremely small doses (less than those recommended by Noon 

 and Freeman in treating European hay fever) appear to give the 

 best results. One case, for example, received four injections at 

 intervals of four days, the amounts being .12, .18, .24, and .36 c.c. 

 of a one in one hundred thousand extract of ragweed pollen, and 

 showed at the end of this period a fifty-fold increase in resistance. 

 Another case recently immunized against spring hay fever for 

 experimental purposes, received three doses of timothy pollen 

 extract, I c.c, iH c.c. and 2 c.c. of a solution of one in five million 

 at intervals of six days, and at the end of this period exhibited a 

 hundred-fold increase in resistance. In another case in which 

 the resistance had already been raised by previous treatment a 

 thousand-fold, a dose of 2Y2 c.c. of a one in one hundred thousand 

 solution produced urticaria, dizziness and other unpleasant symp- 

 toms referred to in the preceding paper and obviously constituted 

 an overdose. The employment of doses in excess of 1 c.c. of one 

 in one hundred thousand is unnecessary, possibly dangerous and 

 certainly to be avoided. That the changes noted above are not 

 due solely to the development of natural immunity in the course 

 of the disease is proved by the fact that three cases after experienc- 

 ing typical hay fever symptoms for two or three weeks were 

 immunized in the middle of the season and immediately showed a 

 marked improvement, and three cases treated long after the close 

 of the season rapidly developed a greatly increased resistance 

 to the pollen extract employed. The specific nature of the im- 

 munity developed by injecting specific pollen extracts was proved 

 in two cases suffering from both spring and autumnal hay fever, 

 one of whom, Mrs. K., was recently partially immunized against 

 timothy without changing the ragweed sensitiveness, the other, 

 Miss R., being similarly immunized against ragweed without 

 affecting the timothy resistance (see table). 



Mrs. K. 



Initial. 



200 



Maximum. 



200 



Miss R. 



Initial. Maximum. 

 200 800 



200 



400 



200 



200 



