88 REPORTS OF INVESTIGATIONS AND PROJECTS. 



of 15 and 30 again. The structures in the germ-plasm are thus inherited 

 exactly like the somatic characters ; and this is the first time that such par- 

 allelism has been traced. 



What induces mutations in the germ-plasm is not exactly known, yet it can 

 not be doubted that they frequently result from the direct action of certain 

 environmental agents. Years ago Bonnier transplanted alpine plants to the 

 lowland and vice versa and got certain modifications of their germ-plasm as a 

 result, so that their descendants, when reared in their former ancestral homes, 

 for a generation or two at least, were quite dissimilar from their cousins that 

 had not been transplanted. Tower (Carnegie Institution of Washington pub- 

 lication 48) states that he found a similar effect on the color of transplanted 

 potato-beetles. Dr. F. E. Lutz finds reason for concluding that climatic con- 

 ditions similarly have determined the shortening of the wings of the northern 

 crickets. The view is strengthened by the results of experiments which seek 

 to modify the germ-plasm directly. Some years ago our correspondents, M. 

 Standfuss and E. Fischer, of Zurich, were able, by abnormal temperature, to 

 alter permanently the germ-plasm of certain moths. Tower has done the 

 same with beetles, MacDougal with plants by chemical means, and R. H. 

 Johnson has gained results still unpublished that are probably similar to those 

 of Tower. Some efforts were made during the year with the assistance of 

 Prof. C. C. Guthrie, of St. Louis, to influence the germ-plasm of poultry di- 

 rectly by chemical means, but without result. It is proposed to extend at this 

 Station next year the work of inducing mutations. 



The modification of the germ-plasm by the action upon it of the soma is 

 still believed in by most people, as well as a respectable body of biologists. 

 Recently Prof. C. C. Guthrie (Jour. Exper. Zoology) of the Medical School 

 of Washington University engrafted ovaries from a black hen upon a white 

 one and vice versa. He is confident that the transplanted ovaries were func- 

 tional and produced eggs which, however, showed in the embryo that devel- 

 oped from them some influence of the foster-mother. His work, involving a 

 somewhat difficult technique, is important, although I disagree with Guthrie's 

 interpretation. Upon my invitation, Dr. Guthrie spent some time at the Sta- 

 tion during the winter. Experiments somewhat in this line were started here 

 and future lines of work considered. At present no satisfactory proof that 

 the germ-plasm derives specific characteristics from the soma is forthcoming. 



In contrast with the foregoing still difficult and uncertain method of influ- 

 encing the germ-plasm is a method of very great certainty, yielding results of 

 such interest that the great bulk of our studies so far have been made with it. 

 I have spoken of the stream of germ-plasm ; in reality it is a very complicated 

 affair, composed of many tributary, parallel streams, cross-cuts, and anas- 

 tomoses. They resemble rather the inextricable network of bayous, charac- 

 teristic of deltas or other flat, irrigated countries. For in all sexually repro- 



