Frederick Adams Woods 319 



do not come from any cells that have given up their embryonic char- 

 acter or gone into building any part of the body, nor do sexual cells 

 ever go into body formation." This he considered only an hypothesis 

 without much basis of observation. 



This hypothesis was taken up by Weismann, in 1883, who, like ISTauss- 

 baum, insisted that such was inconsistent with Darwin's hypothesis of 

 pangenesis and that the reason why the offspring is like the parent is 

 because some germinal cells are saved out unchanged. 



As Francis Galton expressed it, the individual is merely the " trustee " 

 for the cells that maintain the species. 



It seems to me that the facts about the primitive ova in the dog-fish 

 amply bear out the hypothesis of ISTaussbaum. while regarding Weis- 

 mann's later contentions concerning the inheritance of acquired char- 

 acteristics, even if such early origin of germ-cells were proved by finer 

 methods to be the condition in the higher vertebrates as well, his con- 

 tention would not be proved, though ^s far as it went, it would be 

 strengthened since there would be more reason still for looking upon the 

 primitive ova and the offspring as well, as collateral witli, rather than 

 a part of the parent.' 



Finally. I wish to express my obligations to Dr. Charles S. Minot for 

 his many useful suggestions during the progress of this research. 



BIBLIOGRAPHY. 

 Balfour, F. M., 78.1. — Development of Elasmobranch Fishes. Chap. VI. 

 Bea;rd, J., oo-i. — Morphological continuity of the g-erni-cells in Raja 



batis. Anat. Anz., Dec, 1900. 

 EiGENMAX>', C. H., 91. 1. — Precocious Segregation of the Sex-cells in 



Micrometrus Aggregatus. Journ. Morph., V. 481-492. 

 , 95.2. — The History of the Sex-cells from the time of Segre- 



g-ation to Sexual Differentiation in Cymatogaster. Trans. Amer. 



Micros. Soc, XVII, 172-173. 

 Hacker, V., 97.1. — Die Iveimbahn von Cyclops. Arch. f. Mikros. Anat., 



XLIX, 35-91. 

 His, W., 00.2. — Lecithoblast u. Angioblast der Wii'belthiere. Abhandl. 



Math. Phys. Classe K. Sachs-ges. Wiss., XXVI, 173-328. 

 JuNGERSEN, H. F. C, 89.1. — Beiti-age zur Kenntniss der Entwickelung 



der Geschlechtsorgane bei den Knochenfischen. Atbeit. Zool. 



Zoot. Institut., Wiirzburg. IX, 89-219. 

 MiNOT, C. S.. 94.1.— Gegen das Gonolome. Anat. Anz., IX. 210-213. 



2 Beard's latest article, "The Germ Cells of Pristiurus," which appeared (Anat. 

 Anzeiger, xxi, 50) after this article was in type, does not give results wholly in ac- 

 cordance with my own. 



