PREFACE 



ONE of the worst difficulties, which the medical and veterinary officer 

 practising in the tropics has to contend with, is that of obtaining 

 the necessary literature, and there is perhaps no subject in which 

 this difficulty has been more felt than in applied entomology. The 

 many excellent textbooks on general entomology are of little service, 

 as they do not deal with the practical applications of the subject to 

 sanitation, or with the particular forms with which the medical officer 

 is concerned ; the special papers, with the exception of those of the 

 last three or four years, are scattered in a hundred different journals, 

 to few of which the worker abroad can have access. With the advent 

 of journals specially devoted to the subject the current literature has 

 now become available, and it is possible to keep one's knowledge up 

 to date without an undue expenditure of time or money, but the 

 difficulty regarding the older work, much of which is of a very high 

 order, remains the same. Many important papers are not to be found 

 outside the larger libraries, or can only be purchased rarely and at a 

 high price. 



It is particularly with regard to the practical points which come 

 up in the course of experiments such as any medical officer may be 

 called upon to carry out before practical sanitary measures directed 

 against the insect carriers of disease can be adopted that the isolated 

 worker finds himself at a loss. Detailed accounts of the methods 

 employed in breeding and manipulating insects and ticks in the labora- 

 tory, or of the internal anatomy of disease-bearing forms, are only 

 to be obtained, if at all, by a search through a very large mass of 

 literature in many languages. In too many cases the writers of papers 

 confine themselves to a discussion of results, omitting altogether or 

 giving only a brief note on the methods by which these have been 

 obtained, and assuming a knowledge of the internal structures of 

 insects which the ordinary medical man cannot fairly be expected to 

 possess. In very many instances, even among the more familiar 

 insects, information of the particular sort which is required for the 

 successful carrying out of experiments is not to be found in any 

 publication. We know of no account, for instance, of a method of 



