240 



Scientific Proceedings (115). 



The uteri of the 2 sensitized pigs and one normal pig were 

 tested by the Dale method on January 26 and 27, 1921, with some 

 mixed high and low ragweed pollen extract kindly given us by 

 Dr. Robert Cooke. 



3 c.c. of this extract when added to the bath of 200 c.c. of 

 Ringer's solution had no effect- on the normal uterus. 3 c.c. of 

 the same pollen extract produced marked contraction and spasm 

 on one horn of guinea pig uterus No. 1122, and 29 minutes later 

 this horn was found desensitized to 3 c.c. of our Na 2 C0 3 extract. 

 The second horn of uterus No. 1122 was found very irritable and 

 could not be used. Both horns of the uterus of sensitized guinea 

 pig No. 1 121 responded with marked contraction to 1 c.c. and 0.5 

 c.c, respectively, of Dr. Cooke's extract. For records of this 

 experiment see curve. 



It would seem, therefore , hardly possible to doubt that rag- 

 weed pollen is antigenic and that the negative results obtained by 

 other workers were probably due to their not having employed 

 adequate methods of sensitization or sufficiently sensitive tests. 

 We may, therefore, assert the antigenic nature of ragweed ex- 

 tracts, without wishing at the present time to draw any theoretical 

 conclusions as to the anaphylactic nature of hay fever. 



119 (1701) 



The early effects of conjugation on the division rate of Spathidium 



spathula. 



By LORANDE LOSS WOODRUFF and HOPE SPENCER. 



[From the Osborn Zoological Laboratory, Yale University.] 



Conjugation occurred readily in a pedigree culture of Spathi- 

 dium spathula and therefore experiments were started to determine 

 the effects of fertilization in the life history of the organism. Dur- 

 ing the first six months of the work, more than sixty lines were de- 

 rived directly or indirectly from, the parent line by conjugation. 

 Some of the exconjuganl lines studied represent the Fi, F 2 , Fs, and 

 F4 generations. All the lines which are compared were bred 

 under identical cultural conditions. 



A comparison of the number of generations attained by each 



