SCIENCE 
Fripay, May 17, 1912 
The Present Status of the Genetics Problem: 
DR. Wi. J. SPILDMAN 520.00. sceeec ers cece 
The Peruvian Expedition of 1912: PROFESSOR 
JMTRAM BINGHAM ..............0..-0000% 767 
Samuel Butler and Biological Memory: PRo- 
FESSOR VERNON Li. KELLOGG ............. 769 
The Death of Nettie Maria Stevens ........ V7 
Scientific Notes and News ...........-..... 771 
University and Educational News .......... 773 
Discussion and Correspondence :— 
The Occurrence of Stibnite at Steamboat 
Springs, Nevada: J. CLAUDE JONES. 
Cerium: PROFESSOR B. K. EMERSON. Pop- 
ularizing Sciences: C. R. ORCUTT ........ 775 
Scientific Books :— 
Kelly’s Cyclopedia of American Medical 
Biography: Dr. F. H. Garrison. Case’s 
Revision of the Cotylesauria of North 
America: PROFESSOR S. W. WILLISTON. 
Abbott on the Home Life of the Osprey: 
ProFEessor Francis H. Herrick. Tezt- 
book of Botany for Colleges and Universi- 
ties: PROFESSOR CHARLES H, BESSEY ..... 777 
Special Articles :— 
The Photoelectric Effect: PRoFESSoR O. W. 
RICHARDSON, Karu T. Compton. The Oc- 
currence of a Sex-limited Character in Cats: 
(Ob Op IbigiNAD, GoooeccusKecdoooaaooneooedG 783 
The American Philosophical Society: Pro- 
FESSOR ARTHUR WILLIS GOODSPEED ...... 785 
Societies and Academies :— 
The Tennessee Academy of Science: Wi- 
BuR A. Neuson. The Academy of Science 
of St. Lowis: Dr. GEorGcE T. Moorr. The 
Torrey Botanical Club: B. O. DopGE ..... 794 
MSS. intended for publication and books, etc., intonded for 
feview sheuld be sent to the Editor of Science, Garrison-on- 
Hadson, N. Y. 
THE PRESENT STATUS OF THE GENETICS 
PROBLEM? 
THE problem of heredity has been at- 
tacked in four principal ways. Galton 
developed to a high degree what we may 
call the statistical method. His most im- 
portant conclusions are embodied in his law 
of ancestral inheritance and his law of 
regression. According to the former, the 
two parents together contribute one half of 
the total inheritance of an individual, the 
four grandparents one fourth, the eight 
great-grandparents one eighth, and so on 
indefinitely. The law of regression at- 
tempts to state the average deviation of a 
fraternity from the mean of the general 
population in terms of the average devia- 
tion of the two parents. Recent investiga- 
tions have shown that neither of these laws 
is true except for averages of large num- 
bers of cases, and not in all cases even then. 
They are not applicable to individual cases, 
and are hence of no importance in the mod- 
ern science of genetics, however important 
they may be in statistical problems in gen- 
eral. 
In recent years the methods used by 
Galton have been developed by Pearson 
and others into a highly mathematical 
treatment of the subject of heredity, which 
has given us important means of dealing 
with the precision and reliability of data 
and enabled us to study certain types of 
correlation to advantage, but which has 
otherwise had comparatively little influence 
on the progress of genetics. The study of 
correlation between hereditary characters 
by statistical methods has not as yet led to 
1 Presidential address before the Washington 
Botanical Society, March 5, 1912. 
