8 



Itagaki 



Such a result is shown 



even abolition of the rhythmic movements. 

 in fig. 5. 



The existence of pregnancy does not appear to have any specific in- 

 fluence on the effect produced by corpus luteum extract upon the uterus 

 of the rat. Usually the effect is that of increase of tone and increase of 

 rate of rhythm of the individual contractions, but in one case out of four 

 which were investigated inhibition was produced instead of increase. 



Sixty-seven experiments were made in all on the rat's uterus. Of these 

 sixty-three were from non-pregnant animals. In fifty-three cases an in- 

 creased contraction was produced. In seven the result was inhibition. In 

 the remaining three no perceptible change was caused. 



Experiments upon the Rabbit's Uterus. 



As a sreneral rule the cornu of the rabbit's uterus is too stiff and thick 

 to be used as a whole, and in these cases the record was made from a 

 longitudinal strip of the wall. In seven cases the uterus was taken from 

 non-pregnant animals, in three from pregnant rabbits. The usual result 



Fig. 6. — Rabbit-uterus, Showing increase of tone and increased rapidity of rhythmic 

 contractions as the result of immersion in corpus luteum extract (5 per cent.). 



in both cases was increase of tone, sometimes accompanied by an increased 

 rate of the rhj^thmic contractions. Fig. 6 may be given as an example of 

 this result. Inhibition was evident in two cases, one non-pregnant and 

 one pregnant. After two days in the ice-chest the ordinary result was 

 still obtainable. A few experiments were made with the rabbit's uterus in 

 situ, an injection of extract being made into the jugular vein. This usually 



