Itagaki 



Method of Preparing the Extracts. 



My extracts were in all cases made from the ovaries of the cow and 

 sheep, the corpora lutea being removed and prepared as soon as they were 

 received from the slaughter-house, i.e. within an hour or two after the 

 animals had been killed. Occasionally the ovaries were kept overnight 

 in an ice-chest at a temperature of from 3° to 7" C. The method which I 

 have used for making the extracts has been as follows : — The corpora lutea 

 were shelled out from the ovaries by the aid of two pairs of forceps ; the 

 capsule or theca of each corpus luteum was then peeled off, and the 

 remainder of the gland was minced and thoroughly pounded in a mortar 

 until it formed a nearly homogeneous paste. Part of the paste was 

 taken and weighed, mixed with a definite amount of Locke's solution, and 

 boiled for a few minutes. It was then rapidly cooled, filtered, and made 

 up to the original volume by the addition of distilled water. The reaction 

 of such an extract is generally found to be neutral. This may be spoken 

 of as extract of fresh corpus luteum. 



The remainder of the corpus luteum paste was spread out on a clean 

 glass plate into a thin layer. This was placed in an incubator at a 

 tempei'ature of 37° to 40" C. for some hours until completely dry. It was 

 then scraped off", transferred to a mortar, ground to powder, and kept in a 

 desiccator. Roughly, the fresh corpus luteum by the process of drying 

 was reduced in weight to one-fifth ; in other words, it originally con- 

 tained about 80 per cent, of water. 



Table I. 



A weighed portion of this dried powdered corpus luteum was taken? 

 when required, mixed with a definite amount of Locke's solution, boiled 

 and cooled. It was then filtered, and distilled water was added to make 

 the solution up to its original volume. The reaction of this solution was. 



