164 



extremely difficult to transplant. It has been shown that in 

 cases of the latter kind — the ericas, for example — there are inti- 

 mately associated with the roots of the plant fungi, without 

 which the plant will not grow. Unless the greatest care is 

 taken to carry with the plant, in the act of transplanting, a 

 sufficient quantity of the associated fungus in a living condition 

 the operation is a failure. In some cases it appears that a plant 

 can make use of other but similar fungi to those to which it is 

 ordinarily accustomed. This seems to apply to some forest trees,. 

 and in that case transplantation can be accomplished without so 

 much difficulty, provided that the necessary fungus is to be found 

 in the soil to which the tree is transplanted. 



In what way these organisms help one another is not easy to 

 decide. It may be that in many cases, as already suggested 

 with the leguminos^e, the lower organism in some way stimulates 

 the higher, perhaps by producing substances which act as stimu- 

 lants, for it has been shown that certain organic and inorganic 

 poisons can act as plant stimulants if administered in suitable 

 doses, although they may be fatal in large quantities. Or it may 

 be that of two organisms, A and B, B may use up and destroy 

 some substances produced by A, which, if allowed to accumulate 

 beyond a certain limit, would destroy the activity of A. Many 

 cases are known in which an organism produces by its activity a 

 substance which either destroys or greatly hinders its own 

 growth. For example, yeast produces alcohol from sugar, but 

 yeast ceases to act if too much alcohol is present. Whatever be 

 the explanation it is becoming increasingly evident that we are 

 here dealing with a far-reaching principle of nature. 



Now, the question naturally arises whether any light is 

 thrown by all this upon results in this country, or whether the 

 investigation of the phenomena to which I directed your atten- 

 tion is likely to be of any importance in connection with the 

 future development of agriculture in South Australia. Reply 

 might be made that if in the opinion of eminent authorities the 

 pursuit of such investigations is likely to be of the highest im- 

 portance to agriculture generally then as a matter of course they 

 will be of importance here. But certain results have been ob- 

 tained in this State which deserve special attention. Professor 

 Lowrie has shown as the result of experiments at Roseworthy 

 that nitrogenous manures when added to phosphatic manures in 

 that and similar districts do not produce anything like so much 

 additional effect as they do in Europe, though in some experi- 

 ments at Millicent he informs us that he got a much greater 

 effect. He states that very probably the difference between the 

 two cases may be due to the fact that in Europe (and this 

 applies also to Millicent in comparison with Roseworthy) with a 



