434 



Prof. M. Ward. On the 



[Nov. 21, 



contact, and not unfrequently one finds several root-hairs all fastened 

 together at the common point of infection (fig. B). This highly 

 refringent spot is obviously the " bright spot " referred to in my pre- 



Koot-hairs of the pea in process of being infected. A, two very young hairs with 

 the germ in the cellulose wall ; B, three root-hairs in the same condition. In C 

 the infecting tube has commenced to grow down the root-hair. The latter is dis- 

 torted at the point of origin of the tube. The beginning of the distortion is appa- 

 rent in A (the left-hand figure). A and C = Zeiss J. imm. ; B == E obj. 



vious paper as the point of infection from which the infecting 

 filament takes origin. It soon grows larger, and develops a long 

 tubular process (fig. C), which grows down inside the root-hair, and 

 invades the cortex, passing across from cell to cell, as described in 

 1887. 



As a matter of fact, then, the "bright spot " is the point of origin 

 of the infecting filament ; and, as a matter of inference from the 

 experiments, it cannot but be developed from one of the " bacteroids " 

 or " gemmules " of the tubercles. This attaches itself to the root- 

 hair, fuses with and pierces the delicate cellulose wall, and grows out 



