14 PRESIDENTS ADDRESS. 



of climate and soil has also recently been brought home by ex- 

 periments undertaken in Natal. Some of you will remember 

 that Mr. Robertson, of Grahamstown, proved in an unmistakable 

 way that the plant Senecio lotifolia. collected in that part of the 

 country, proved to be very fatal when fed to horses and cattle 

 The experiments in Xatal. carried out on the same class of 

 animals with the same plant, proved harmless. 



You will grasp the complexity of these subjects when you 

 remember that, in order to fully understand and explain them, 

 a combination of a number of sciences is necessary. i'ic, Path 

 olo^y. (ieology. Botany. Chemistry. Climatology. Meteorology 

 and Physiology. Better subjects could hardly have been found 

 to illustrate how comprehensive investigations may become in a 

 matter which at first sight seems purely and simply a problem 

 for the veterinarian. This point brings me back to some remarks 

 laised before. It is only possible for an applied science, such as 

 that for investigating into the cause of the disease, to progress 

 when the other sciences on which the applied one is based are 

 advancing at the same time or. still better, are ahead of it. This 

 applies strikingly to the case in point. Of the physiological 

 effect of grasses and plants under the various conditions of 

 climate and soil in South Africa we know nothing as yet. T 

 am glad to state that the Minister of Agriculture, to whom T 

 have explained the necessity of such investigations, has pro- 

 mised to add a branch for physiological research on to the 

 laboratory under my control. But an investigation of this nature 

 must be thoroughly undertaken, and in order to be fruitful it 

 must go band in hand with chemical and biological investigations 

 of the nature of the soil as well. The necessity for such investi- 

 gations has frequently been pointed out. Professor Pearson 

 some years ago advocated the erection of botanical gardens in 

 South Africa in areas representing the various conditions of 

 climate and soil, and one of his strong arguments was the 

 economical importance such establishments would have. Our 

 recent investigations bear him out, and should bring home the 

 value of such institutions. For many years Dr. Juritz preached 

 the necessity of a systematic and thorough chemical survey of 

 the soil of this sub-continent. In his recent presidential address 

 to the Chemical Society, he clearly pointed out that, so far. inves- 

 tigations have not been undertaken as necessity demanded, and I 

 fully endorse these remarks. The conclusions I put before you 

 in connection with the disease caused by plants show you the 

 necessity in the first instance of scientific research into soil and 

 vegetation. But a good deal is required if we intend to make 

 further progress in the understanding of the disease as already 

 described, and of many more not touched on at all. The neces- 

 sity for a general biological survey of all South Africa becomes 

 obvious. Particularly the geographical distribution and seasonal 

 occurrences of plants and animals, the connection between 

 climate and soil with flora and fauna, will have to be thoroughly 



