82 TRANSACTIONS OF THE [Sess. lxxxm 



was vague and the principles were little understood. The 

 whole subject assumed new interest after Gregor Mendel's 

 experimental work. Mendel (1822-1884) made experi- 

 mentS: mainly on peas, and published his results in 1865, 

 but the paper was overlooked till 1900, when translations 

 appeared in several countries. Numerous investigators 

 made new experiments, and the past twenty years will 

 always stand out as a historical period in hybridisation. 

 It is too optimistic to assume that Mendel's Laws have 

 solved all the difficulties, but it is safe to say that they 

 mark a great stride. As a result, it is possible to raise 

 new varieties of crop-plants within a few years. If one 

 variety has high yielding powers and another variety has, 

 say, hardiness, these can be combined by methods which 

 are now fairly well understood. Thus the leading barley 

 in the Lothians, " Plumage Archer," is a cross made in 

 1905. Biflf'en's crossings of wheat since 1900 have yielded 

 varieties with superior baking qualities, and others that 

 are resistant to wheat rust. 



PatJtology. — The study of disease in plants has made 

 great progress. Previous to 1870 much had been done in 

 identifying fungi, insects, and other parasites on plants, 

 but far more attention was given to the fungus or other 

 organism than to the plant affected. In the early nine- 

 teenth century Link was doubtful whether the spores of 

 fungi could germinate. Persoon in 1818, while admitting 

 that some fungi ai'ose fi-om sjjores, resorted to spontaneous 

 generation to explain the origin of others. The real 

 awakening came from France, when the brothers Tulasne, 

 between 1850 and 1865, worked out the life-history of 

 rusts and smuts, of ergot, and the sexual organs of 

 Peronospora. The newer school of plant pathologists owe 

 much to De Bary and Bret'eld and tlieir pupils, so that the 

 present era of accurate laboratory methods, pure cultures, 

 and inoculation had their origin since 1870. It was not, 

 however, till abcjut twenty years ago that our universities 

 extended facilities for teaching and research in plant 

 pathology, and the stimulus came maiidy from the agri- 

 cultural schools. The recognition of the value of colonial 

 crop-plants has given great op])ortunities to many of our 

 home-trained mycologists, so that within recent years a 



