1921-22.] BOTANICAL SOCIETY OF EDINBURGH 79 



laying down of grassland. An early method was to grow 

 corn till the land was foul, then it was left to become a 

 grassland of some sort. Another method was to sow the 

 sweepings of the hay-loft. Later came the practice of 

 sowing rye grass and clover seeds, and this was almost 

 universal fifty years ago. About 1870 "natural grasses" 

 were much discussed, but it was only the pioneer who 

 ventured to use them. Now every farmer knows some- 

 thing of cocksfoot, timothy, and other grasses, and many 

 are experimenting actively to obtain the most productive 

 grassland for their farms. In recent years great results 

 have been obtained by using " wild " white clover, and 

 there are indications that the red clover seed now in use 

 will be replaced by better strains of " wild " red clover. 



Nutrition of Plants. — During the seventeenth century 

 Van Helmont, Priestley, and others founded this branch of 

 botany, but even in the early part of last century there 

 was, no clear view how a plant obtained its food supplies. 

 About 1840 the forceful Liebig and his pupils established 

 the " mineral " theory of plant nutrition, and this was 

 eagerly adopted by agricultural science, so that nitrogen, 

 phosphates, potash, and calcium became part of the 

 ordinary talk of the market-place. A result of this period 

 was a worship of the chemical analysis and a serious 

 neglect of the living plant. There is still a remnant of 

 this sentiment, but one of the greatest advances of the 

 past fifty years has been the recognition that the living 

 plant is not understood when it has received a name. Our 

 period has seen a marked extension in the accommodation 

 for botanical teaching and study in almost every univer- 

 sity, including the Scottish ones. Much of this develop- 

 ment has been in the direction of plant physiolog3^ The 

 publication of Sach's lectures in 1865 brought order out of 

 chaos, and the textbook " Physiology of Plants," by Vines 

 in 1886, first revealed to English readers this important 

 new domain of botany. There can be no doubt that experi- 

 mental physiology has been of great importance in the 

 successful growing of crop plants. 



Soil Biology. — Another great development is the re- 

 cognition that not only is there life in the plant, but there 

 is life in the soil. About 1870 Pasteur suggested that the 



