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Since our last meeting an important book relating to plant diseases has ap- 

 peared, viz. : Dr. Stevens' "Fungi which Cause Plant Diseases". This work fills 

 a long- felt want, inasmuch as it brings together into a compact volume a large 

 amount of valuable information scattered through many foreign publications 

 which are often unavailable to English-speaking students. With the aid of 

 Stevens' book the student of fungi is now in a position to determine without 

 much trouble the genus to which his specimen belongs. 



Introduction. 



INSECTS AND DISEASE 



By W. Lochhead, Alacdonald College. 



Although this subject does not properly come under the scope of a Society 

 for the Protection of Plants from Insects and Fungous Diseases, yet on an occa- 

 sion of this kind w^hen all the papers deal directly with the protection of plants 

 I have taken the liberty of going a little afield and discussing the relationship of 

 insects to disease in man, a matter of great and growing importance at the present 

 time. As entomologists we are all interested in the habits of insects, whether 

 they injure plants or animals, and experience shows that frequently the informa- 

 tion gained by workers in one field is of great value to workers in the other. It 

 is often impossible to keep departments strictly water-tight. f 



Disease-Carrying Insects. , 



During the last fifteen years important discoveries have been made regarding 

 the transmission of certain diseases by certain insects such as the mosquitoes, 

 house-flies, stable-flies, gad-flies, tsetse-flies, fleas, bed-bugs and ticks. 



Brues and Sheppard divide the diseases that are carried by insects into three 

 groups : — 



Group A. — Characteristically insect-borne diseases; 



Group B. — Often insect-borne diseases; 



Group C. — Possibly insect-borne diseases. 



Under Group A are included malarial fever, yellow fever, filariasis, sleeping 

 sickness, typhus fever, bubonic plague. African tick-fever. Rocky Mountain spotted 

 fever of man, and Nagana and Texas fever of horses and cattle. 



Under Group B. are included typhoid fever, cholera, dysentery, diarrhoea, 

 tuberculosis, septicaemia. 



Under Group C. are included anthrax, rabies, pellagra, hookworm, beriberi, 

 black water and rdapsing fever of man; and equine infectious anaemia. 



Anopheles Mosquito and Malaria. 



Malarial fever and ague were common in Canada a generation ago, and our 

 fathers vaguely attributed the disease to the presence of swamps whose numbers 

 have fortunately been greatly reduced since by drainage. 



The story of the discovery of the causal organism and of its life history in 

 connection with the Anopheles mosquito is one of the interesting chapters in 

 modern biological investigation. The organism belongs to the amoeboid Protozoa 

 and was discovered by Laveran, a French army surgeon, in 1880. The part of 



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