20 



Itagaki 



appearances. The results were as follows:— (1) As a general rule the 

 increase of tone was greater in extracts made from big corpora lutea, 

 especially those having marked orange colouring. (2) As a general rule 

 the extracts from large corpora lutea with yellow colouring also produced 

 increase of tone. (3) Far less contraction was produced by extracts made 

 from small corpora lutea with yellow colouring. Of fifty corpora lutea 

 which were separately investigated, thirty-three of which belonged to the 

 laro-er class, and the rest to the smaller, most of the first caused marked 

 increase of tone. Of those which caused no marked increase of tone, 

 seventeen were small yellow corpora lutea with thick theca. Amongst 

 these, the extract of one caused inhibition and decrease of tone instead of 

 increase of tone. Of the thirty-three extracts obtained from the large 

 corpora lutea, six produced no marked change in uterine contraction. 



Experiments were also made to determine whether differences of effect 

 were obtainable from corpora lutea of pregnant animals as compared with 

 those of non-pregnant animals. By far the greater number of the corpora 

 lutea which I have used were from the cow, and these were always non- 

 pregnant animals. Since the corpus luteum of the pregnant cow was not 

 obtainable, the corpus luteum of pregnant sheep was used in order to 

 determine if the difference of the result were due to pregnancy. The ex- 

 periments show that there was no difference in this relation. 



Table XIV. 



Chemical Investigation. 



It appears therefore probable that there are two antagonistic principles 

 present in the corpus luteum, both of which can be extracted with Locke 

 fluid, although in the great majority of cases the principle which pro- 

 duces inhibition is in far less amount or is absent altogether. I have 

 made a series of attempts to separate these supposed antagonistic principles. 



I first tried the effect of extracting with alcohol and employing Locke 

 extract of the dried alcohol extract. The method of extractinor was as 

 follows : — The corpora lutea were minced, ground in a mortar, and spread 

 on a clean glass plate to dry, in the manner previously detailed. Over 

 some of the dried powder cold absolute alcohol was poured, shaken several 

 times, and the yellowish supernatant fluid when clear was decanted off and 

 filtered. This procedure was repeated with successive portions of alcohol 



