EFFECTS OF CHANGES IN MK1>HM. 



27 generations. Series 72, 97, 98 showed the stimulating eft', 

 nf the beef about the 6oth-75th generation. Series M and 05 

 failed to respond to the beef until a still later age and might be 

 considered -low maturing series. Series 95 gave indications 

 long period of immaturity, showing distinct depre-non in the 



: as late as the iO2d generation. Beef apparently i- 

 depre--ant in the early generations and a Mimulant in later 

 periods of the life history. 



TABLE II. 

 i in EFFECTS <w Bsn FEEDING DURING A LATER PERIOD IN THE LDTE HI-IKY. 



(f) Direct Response of Old Protoplasm to Beef Extract. 

 Table III. shows the results of feeding old series with the beef- 

 Hour medium. Kleven experiments were carried out on proto- 

 var\ing in it- .iu;e tVom the 2ioth to the 37Oth generation 



