and cord of the 7th i^cnercJ.tion is t^renter than in the 8tVi. 



In Plate X ia shown tlie curve of learnin(£, (below) 

 and of relearnlnt; (above) of the 7th and 8th (generations of 

 inbred rats. The 7th tiSneration curve ia shown by the broken 

 ]ine; that of the 8th generation by the solid line. The ordi- 

 nates ^ive the tine in seconds, and the abscissae the number 

 of the day in which such time v/as made. Both curvea in the 

 learning aeries are very irregular, but more particularly that 

 of the 8th tjeneration I'ats. Although irre^'ular, the 7th -^en- 

 eration curve lies below that of the eth except in a few in- 

 stances. After, the first day, the relearning curves are simi- 

 lar and very re^nAlMr, although that of the 6th {generation re- 

 mains below the 7th all the way. But only the best of the two 

 generations were used, four of the 7th and seven of the 8th 

 havinj^ been discarded on account of not having learned the 

 inclined plane. 



