Maech 23, 1917] 



SCIENCE 



295 



fertile. According to Donaldson^ the meno- 

 pause normally occurs at the age of 15 to 18 

 months, although he reports one female which, 

 mated at the age of 22 months, produced a lit- 

 ter of one. The young was not reared, how- 

 ever. 



Four of our stunted females were mated at 

 various times. The results are summarized 

 in tabular form. Data regarding their early 

 stunting and subsequent resumption of growth 

 have been published elsewhere.* In every case 

 the female was not remated until some time 

 after the birth of a litter, as the maximum 

 number of broods which she could bear was of 

 much less interest than the final age at which 

 she was capable of producing young. Although 

 none of these rats began breeding until they 

 had reached an age when normal rats are com- 

 monly believed to be approaching the meno- 

 pause, they produced from three to six litters of 

 young and successfully reared all but a few of 

 them. Their young were apparently as vigor- 

 ous as those born of younger mothers. Hence 

 the menopause has been postponed long beyond 

 the age at which it usually appears. In view 

 of this, and the added fact that less than one 

 third of our stock rats have reached an age of 

 more than two years, whereas all of these 

 stunted females lived longer, it appears as if 

 the preliminary stunting period lengthened 

 the total span of their life. 



Thomas B. Osborne, 

 Lajtayette B. Mendel, 

 Edna L. Ferry 

 Connecticut Agricultural Exp. Station 



AND SHErriELD SCIENTIFIC SCHOOL, 



New Haven, Conn. 



THE MATHEMATICAL ASSOCIATION 

 OF AMERICA 



The second annual meeting of the Mathematical 

 Association of America was held at Columbia Uni- 

 versity, New York City, on Thursday, Friday and 

 Saturday, December 28-30, 1916, in afiUiation with 

 the American Association for the Advancement of 

 Science. There were 184 persons present at the 

 various meetings, including 141 members of the 

 association. The first meeting was a joint session 



« Osborne, T. B., and Mendel, L. B., J. Biol. 

 Chem., 1915, XXIII., 439; Am. J. Physiol., 1916, 

 XL., 16. 



