PRESIDENT'S ADDRESS. 3 



animals at large are concerned. What has been shewn is 

 that certain animals can be experimentally infected by the 

 bite of the tsetse fly, which is a very different matter. A 

 commission is now at work on this question, but even were 

 it shewn that wild animals were infective agents, their com- 

 plete destruction might only make the flies do tenfold damage 

 amongst human beings, when their usual food was taken 

 from them. At the same time there are stated to be dis- 

 tricts where there is no big game and which swarm with 

 the flies, and vice versa, so that the matter is a most com- 

 plicated one and any rash action would be dangerous and 

 undesirable. Though it is now 14 years since Ross dis- 

 covered in India the connection of mosquitoes with malaria, 

 it is only in November last that the Indian Government has 

 recognised this fact officially and proposed measures for the 

 prevention of malaria by mosquito destruction. The final 

 Report of the Royal Commission on Tuberculosis has now 

 been published, in which the very important fact is stated 

 on incontrovertible evidence, after full experimental investi- 

 gation, that bovine tuberculosis is the same as that found 

 in human beings. This was denied by Koch in 1891, which 

 led to the appointment of this Commission, which, with the 

 consequent legislation, will doubtless do much towards re- 

 moving one source of this disease. Experiments have shewn 

 that flies of various species are liable to become dissemin- 

 ators of disease germs by carrying them attached to their 

 feet, also that they may congregate in houses at a distance of 

 f mile or more from their breeding place, and under certain 

 conditions they may undoubtedly be a danger. Recent 

 experiments tend to confirm the belief that boring shells 

 (Pholas and Saxicavd) work by mechanical and not by chem- 

 ical means. The movement is chiefly produced by the 

 formation of a vacuum by the mantle and foot of the animal. 

 Some of the lower forms of life vary very much in shape 

 and appearance in the same species, sometimes locally, 

 sometimes seasonally, or without any obvious cause. This 

 is often the case with moths and butterflies to such an extent 



