14 THE WOMBAT. 



What a wonderful change has been produced during t he- 

 last few years by the discovery of the germ origin of disease. 

 It seems strange indeed to think that the inflammation which 

 follows a wound, whether the result of an accident or of a 

 surgical operation, comes within the domain of the naturalist to 

 explain ; — or that the disease which claims no less than one- 

 seventh of the human race as its victims — commonly known 

 as consumption — can now be explained by the teachings of 

 natural history. Tuberculosis in the lower animals is identical 

 with consumption in the human, and furnishes another 

 example of their relationship ; the disease in both cases is due 

 to the growth and development of germs or plant life. It 

 may seem strange at first hearing that plants grow and 

 reproduce themselves in our living and circulating blood, but 

 such is the case, and it is as a result of the observations of 

 our most devout workers in natural history that we are 

 enabled to employ measures to prevent the spread of such 

 diseases. The world-wide practice of inoculation is due to 

 the result of such investigations and experiments. Thus you 

 see that the study and observation of plant life are not only 

 applied to the vegetation of mother earth with its specific and 

 physical differences, but also to the agencies which produce 

 the greatest mortality amongst mankind. Hence I repeat it 

 is necessary to study their modifications and relationships, 

 their dependence on each other, and the effects of meteoro- 

 logical conditions, to make natural history complete. 



Again the ravages of insects and their larvae are a con- 

 stant source of annoyance and loss to persons engaged in the 

 cultivation of the soil ; in fact it is impossible to form anything 

 like a correct conception of the enormous amount of damage 

 annually caused by insect pests. It is only by observing the 

 earliest times of appearance and recording the same that 

 preventive measures can be employed with anything like a 

 prospect of success ; a careful and systematic inquiry into the 

 foodplants of the larvae of all destructive species is needful ; 

 the general time of their first appearance ; and the result of 

 meteorological conditions affecting their food supply. For I 

 can say from my own limited observations that the food 

 supply regulates to a certain extent the amount of insect life. 



It is now well-known — and I believe I was one of the first 

 in Victoria to point it out — that almost every genus of insects 

 is identified with certain natural orders of plants. For 

 instance, if I see an "Admiral" butterfly flitting about I 

 know in a moment to my own satisfaction that the stinging- 

 nettle flourishes in the district, for its larva feeds on that 

 plant and no other. I could multiply examples of this kind 

 to occupy the next two hours, but this is sufficient to show 

 you that if we study insects and their history it brings us into 



