356 DARWINISM TO-DAY. 



it may be that the origin has been primarily excretory and 

 only secondarily protective or aesthetic ?" 



The plain truth is that the satisfactory, all-explaining ex- 

 planation of secondary sexual characters and sexual dimor- 

 phism as a whole is yet to be formulated. 



APPENDIX. 



1 At some time between 1855 and 1865, Gregor Johann Mendel, 

 an Augustinian monk in the small Austrian village of Briinn, car- 

 Mendel and ried on pedigree cultures of peas and some other 

 his work, plants in the gardens of his cloister. From this work 



he derived data that he read, together with his interpretation of 

 their significance, before meetings of the Natural History Society 

 of Briinn, and which, in the same year of their reading, 1865, were 

 published under the title "Experiments in Plant-hybridisation," in 

 the Abhandlnngen (Vol. IV.) of the society. Mendel was the son 

 of a peasant and had been educated in Augustinian foundations and 

 ordained priest. For two or three years he studied physics and 

 natural science in Vienna, and refers to himself as a student of 

 Kollar. He became Abbot of his cloister, and was for a time 

 president of the Briinn Natural History Society. Such are the 

 essential details of the education and situation of the man whose 

 name will undoubtedly live forever in the annals of biological 

 science. For the observations, experiments, and conclusions of 

 Mendel on inheritance have taken their place already as matters of 

 fundamental importance in the study of heredity. It would take 

 us too far afield even to outline Mendel's work and derived "princi- 

 ples of heredity," but the interested reader can find an admirable 

 exposition and discussion of them (together with translations of 

 Mendel's own papers) in Bateson's "Mendel's Principles of Hered- 

 ity," 1902. 



For an excellent exposition of Mendel's work and other similar 

 work by botanists, see Lotsy, J. P., "Vorlesungen iiber Descendenz- 

 theorien," Vol. I, chap, viii, 1906. 



Cuenot, in L'Annee Biologique, Vol. VII, for 1902, pp. 58-77, 

 gives an excellent review of the work of Mendel, de Vries, Cor- 

 rens, and Tschermak ; and a bibliography, relating to the so-called 

 Mendelian laws of the principles of heredity. 



Bateson, in "Progressus rei Botannicae," Vol. I, pp. 368-468, 1907, 

 gives a complete abstract of the nature of the work and its results 

 which has been done on the Mendelian problem from the time of 



