326 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



11. The presence of bacteria in the cells of a tubercle pre- 



vents the infected cells from forming starch granules. 

 Uninfected cells do not attain the size usually 

 reached by infected cells. The larger size of in- 

 fected cells is due to increased pressure, probably 

 also the greater irritation, in these cells. 



12. The bacteria cause the degeneration and almost com- 



plete destruction of the nuclei of the cells in which 

 they occur. 



13. The infection strands grow definitely, chemotropically, 



toward the daughter-cells formed by the tubercle 

 meristem, and seem also to grow definitely toward 

 the nuclei of the cells into which they penetrate. 



14. Infected cells soon lose their power of division, though 



not of growth. 



15. The presence of bacteria in the cells of the tubercle is 



injurious to these cells, and the relation of the bac- 

 teria to their host-cells is parasitism. 



16. It is difficult to understand how the leguminous plant 



as a whole can profit by an association which is 

 injurious and finally destructive to the cells in which 

 the bacteria occur. 



17. Intercellular spaces occur in the tissues of root- 



tubercles. Even if they did not, it would not be 

 necessary to assume that the bacteria live anaerobi- 

 cally therein, since the tubercle cells do not live 

 anaerobically. 



Leland Stanford Jr. University, 



Palo Alto, California, 



July 27, 1901. 



