ENTOMOLOGY HOWARD 363 



ing desperately among- themselves, is only just becoming apparent, 

 and offers a field for many keen workers for many years to come. 

 And it is a field of very great promise. It is one of the fundamentals. 

 The complexity of the problem is growing on us. What we once 

 thought simple become the more involved the deeper we go into the 

 subject. But these very complications as they arise should only 

 render the subject the more attractive to the truly scientific mind. 

 Nowhere do we run up against a stone wall ; but the more we observe 

 and the more we study, the more the field opens before us and the 

 closer we come to a true understanding of relations and the more 

 apt we will be to find principles and ideas that will be of value from 

 the human standpoint. 



Insects are a healthy race. They have in these 50,000,000 years 

 bred out the unfit. And their very prolificacy more than compen- 

 sates for the losses caused by occasional epidemics. But in the study 

 of natural control, insect pathology, a largely neglected field, must 

 have more workers. We must know here, just as in every other 

 possible line of insect research, every fact that can be ascertained. 

 Of course, the insect pathologist will be working for an end 

 diametrically opposed to that of the human pathologist, but the basic 

 technique of the latter will help the former, and the causative 

 organisms of disease have a certain zoological or botanical grouping 

 which will render the work of both groups of pathologists at least 

 comparable. There are great gaps to be filled in our Imowledge of 

 the forms of parasitism in which protozoa, bacteria, fungi, helminths, 

 and filterable viruses are concerned. 



In this direction the work of Pasteur on pebrine stands out, and 

 the results of subsequent investigations of this disease have been 

 incorporated in a number of papers, especially by Italian investi- 

 gators. The diseases of bees have been investigated by our own 

 G. F. White and A. P. Sturtevant; and Burri, of Switzerland, 

 Bahr, of Denmark, and Maassen, Bochert, and Zander, of Germany, 

 have contributed to the study of bee diseases. Kudo, of Japan, 

 has worked upon the protozoa of insects, and a number of medical 

 investigators have been led to study the microorganisms in the diges- 

 tive tracts of insects that bite man. 



Paillot, of France, is making profound studies of the micro- 

 organism fauna of the insect body. Metalnikov, of the Pasteur 

 Institute in Paris, has been working on the blood of insects and 

 making studies relative to the problem of immunity, using largely 

 the larvae of the wax moth. Rudolph Glaser and G. F. White, of 

 the United States, are studying the pathology of insects. 



