18 



Itagaki 



on stimulating the distal cut end of one vagus and, after section of the 

 opposite vagus, the depressor action on stimulating the central end, 

 and to endeavour to determine whether these results were influenced 

 by intravenous injection of extract. Twenty experiments were made 

 altogether, ten on rabbits and ten on cats. The results obtained were 

 inconstant. 



Cause of the Differences of Result produced in Different 

 Experiments upon the Uterus by Corpus luteum. 



I have endeavoured to determine the cause of the differences of result, 

 such as increase of tone in one case and diminution of tone in another, 

 which are produced upon the uterus by extracts of corpus luteum. 



I first investigated the effects produced by different strengths of 

 an extract. Within the limits of the dilution employed (O'l per cent, to 

 5 per cent.), the action was similar in each case. These results are 

 exhibited in the following table. The numbers indicate the height of the 

 ordinates in millimetres : — 



Table IX. 



This set of experiments shows clearly that alteration in the strength 

 of the dose does not necessarily produce a difference in effect. It is note- 

 worthy, however, that whereas in most experiments the eflect was in no 

 way proportional to the increase of dose, in one experiment — No. 5 — there 

 appeared to be an almost exact proportion between the effect in pro- 

 ducing contraction and the strength of the dose, I am quite unable to 

 explain this difference. Another circumstance which occurred to me as 

 possibly influencing the result was the condition of pregnancy or non- 

 pregnancy. But it will be seen from what has been already stated that 

 this has no definite influence, for we find an inhibitory effect produced in 

 both the pregnant and the non-pregnant uterus. That the effect is 

 one of the extract and not of the condition of the uterus is shown 

 in the following tables (X., XI., and XII.), which represent experiments 



