PREFACE ix 



portance of their work, in this country at any rate, 

 has not received the recognition which it deserved, 

 probably owing to the absorbing interest of other 

 things which followed so soon after their dis- 

 coveries were made public. To most the ill 

 reputation of the louse remained still due to the 

 fact that it is a disgusting, irritating creature, a 

 symbol of filth, and not to the fact that its 

 presence is a very real danger to the community. 

 During the present year still a third disease, 

 trench fever, has been placed to its discredit, and 

 possibly even now the full extent of its guilt is 

 not known. 



One of the most urgent sanitary problems of 

 the present and the future is therefore the destruc- 

 tion and prevention of lice. Now sanitary 

 problems concern not only the Medical Officer of 

 Health but each one of us, for it is only by 

 individual effort, working in harmony with public 

 regulations, that a really hygienic state can be 

 attained. This is especially true of personal 

 hygiene. Public instruction is therefore neces- 

 sary concerning lice, to correct the errors which 

 exist to-day and to disseminate the knowledge of 

 them which the last few years have produced. 



Those who desire a fuller and more detailed 

 account of the habits of lice, and of the means of 

 combating lousiness, should refer to Professor 

 Nuttall's papers on the subject published in 

 Parasitology, Volumes IX. and X. Here also a 

 full bibliography of the subject will be found. 



