President's Addhkss .Sk( t. I). 153 



xlen from us. Alreadj^ the stud}^ of genetics, since the rediscovery of 

 Mendel's papers, has i^iveii some remarkable instances of interaction 

 between characters belonoino- to distinct so-calle<l allelomorphic pairs, 

 and on these lines perhaps ]Mi-. Bnrbank's almost incredible feats will 

 find their explanation. As Bnrbank's ideals are chiefly to raise fruits 

 and vegetables which are satisfied with a comparatively dry climate, 

 we in South Africa are particularly intereste<i in liis success. In his 

 native country the yield of potatoes alone has been increased by 

 seventeen million dollars ainuially by means of his new^ sorts. 



It is highly desirable that every civilised country should contribute 

 its share in the advancement of pure and applied biological science, 

 and I am glad to be able to state that in spite of our present flnancial 

 depression, our Government is intending at all events to keep up the 

 two experiment stations started by Dr. Nobbs, who cleai'ly laid it 

 down that plant-breeding must be one of their main objects. 



Amongst the numerous other objects of these experiment stations 

 is the investigation of proper manuring. With the artificial produc- 

 tion of nitrogen compounds available as plant food, which seems to 

 be at last established on a commercial basis, the danger arising from 

 the diminution and eventual exhaustion of the supply of nitrates 

 from the depo.sits in Soutli America seems to be considerably reduced, 

 if not eliminated. We are gradual l3^ also, becoming better acquainted 

 with the method of the accumulation of compounds of nitrogen, 

 derived from the atmospheric suppl}^ of elementary nitrogen, by the 

 bacteria in the root-nodules chiefly of leguminous plants. It was of 

 course to be expected that these organisms would not be the onl}^ ones 

 which had this marvellous and, from a chemical point of view, almost 

 inconceivable power of bringing such an extremely inert element into 

 combination. Other bacteria were found to act similarly, and a German 

 lady botanist, Miss Charlotte Ternetz, has recently shown that certain 

 fungi which live s3'mbiotically with the roots of heaths and allied 

 plants, and form the so-called niycorrhizas. can also assimilate free 

 nitrogen. As similar mycori'hizas are found in connection with the 

 roots of man3'- trees, the matter will be seen to be of considerable 

 practical iujportance. Of the five mycoirhiza fungi isolated by Miss 

 Ternetz, three were particular!}^ active, and are undoubtedl}'^ of very 

 great importance, for slu^ found that in her cultures for every gram of 

 dextrose consumed, they fix 22, 18, and 11 mg. of nitrogen respectively. 

 But her results went even further than that. She found that some of 

 the commonest moulds, namelj^ the saprophytic Aspergillas nU/er 

 and Penicilliuin glaiicum, were also able to fix free nitrogen, but in a 

 much less degree. None of the fungi investigated were found to 

 require combined nitrogen for their development, and it is reasonable 

 to hope that these laboratoiy results will have far-reaching practical 

 applications. 



If time had permitted, I should liave liked to dwell at some length 



