114 



THE KINGDOM OF MAN 



Baldwin Spencer's and Haddon's in Australasia furnish 

 examples of what is being done in this way. 



Physiology of Plants and Animals. Since I have not 

 space to do more than pick out the most important 

 advances in each subject for brief mention, I must signalize 

 in regard to the physiology of plants the better under- 

 standing of the function of leaf-green or chlorophyll due 



Bacillus radicola, the para- 

 site which infests the roots of 

 leguminous plants and causes 

 the growth of nodules whilst 

 assisting the plant in the 

 assimilation of nitrogen : (a) 

 Nodule of the roots of the 

 common Lupine, natural size ; 



(b) longitudinal section through 

 a Lupine root and nodule ; 



(c) a single cell from a Lupine 

 nodule showing the bacteria 

 or bacilli, as black particles in 

 the protoplasm, magnified 

 600 diameters ; (d) bacilli from 

 the root nodule of the Lupine ; 

 (e) triangular forms of the 

 bacillus from the root nodules 

 of the Vetch ; (/) oval forms 

 from the root nodules of the 

 Lupine ; (d e /) are magnified 

 1,500 diameters. 



FIG. 32. 



to Pringsheim and to the Russian Timiriaseff, the new 

 facts as to the activity of stomata in transpiration dis- 

 covered by Horace Brown, and the fixation of free 

 nitrogen by living organisms in the soil and by or- 

 ganisms (Bacillus radicola} parasitic in the rootlets of 

 leguminous plants (see fig. 32), which thus benefit by a 

 supply of nitrogenous compounds which they can 

 assimilate. 



