viii PREFACE 



to refer to, and we feel that no further justification for reproducing 

 them is necessary, than that they will become more accessible to those 

 who have the most need of them. At present hardly a dozen of 

 those in the text have appeared in journals which circulate in the 

 tropics, and many have not appeared at all in the English language. 



In accordance with the main object of the book, particular attention 

 has been paid to the description of methods of breeding and laboratory 

 manipulation. The methods which are given are, in the great majority 

 of cases, those which we have used ourselves at the King Institute. 

 It is not claimed that they are the only methods, or indeed the ideal 

 ones, but they have all stood the test of experience, and have been 

 successful in our hands. Where the methods of other workers are 

 described they have been repeated by us in every case in which it could 

 be done. We are only too well aware what an enormous amount of 

 time may be wasted in finding out simple points of technique. 



The sections on internal anatomy also contain a large amount of 

 original matter. With few exceptions the descriptions have been writ- 

 ten and the figures drawn from dissections and sections prepared for 

 the purpose. 



In the list of publications at the end of each chapter, those which 

 include full references to previous work, and those which describe 

 experimental methods, have been specially included. In addition, papers 

 quoted in the text, and those to which we are specially indebted for 

 information, are quoted. It is hoped that the short lists given will 

 suffice to guide the reader to the literature on the subject when a library 

 is available. 



Of the incompleteness and the many imperfections of our work we 

 are well aware, now that it is concluded. We feel, however, that 

 we may justly ask some indulgence if we have omitted points of import- 

 ance, or if the work of others has not always received the consideration 

 which was due, for the book has been written and printed entirely 

 in India, without access to literature other than that in our own 

 possession and in the library of the Institute. We have also been 

 without that friendly advice and criticism from fellow-workers which is 

 of so much service in eliminating errors. On the other hand, a rich 

 collection of material has always been available in the neighbourhood 

 of our laboratory, and if we have failed to make the most of it the blame 

 must be ours. 



It is our pleasant duty to offer thanks to those whose aid has made 

 our task possible. To Sir Harcourt Butler, head of the Education 



