CONTRIBUTIONS TO THE CYTOLOGY OF THE JJACTERIA. 399 



work which lias been done previously on the subject. I shall 

 then give iny own observations — recording them quite in- 

 dependently of the work of others — and reserve a full discus- 

 sion of the whole matter to the final section of the paper. 



My work was begun in the Zoological Laboratory in 

 Cambridge. Afterwards I continued it whilst working in the 

 Zoological Institute in Munich, and at the Zoological Station 

 in Naples.^ Subsequently I was able to add to my results 

 whilst visiting Ceylon in 1909, during my tenure of the 

 Balfour Studentship of Cambridge University. I have com- 

 pleted my work up to its present state at the Imperial College 

 of Science and 'J'echnology, London. I desire here to record 

 my indebtedness to all those who have — in one way or another 

 — assisted in the furtherance of ray work in the various places 

 mentioned. 



HiSTOEIC. 



In the pages which now follow, I have attempted to give a 

 brief historic account of the most important work which has 

 been contributed towards a solution of the problem of the 

 nucleus in Bacteria. It is obviously impossible — in a paper of 

 the present scope — to enter encyclopaedically into all the 

 work which has been done in this connection. 



In dealing with the cytology of Bacteria, it is of the very 

 greatest importance to consider the technique by means of 

 which the various workers have reached their results. I 

 shall therefore make a special point of noting in each case — 

 wherever possible — the methods of fixation, staining, etc., 

 which have been used. When this is done, it becomes 

 apparent that a large part of what has been written upon the 

 bacterial nucleus is practically worthless — owing to the in- 

 adequacy of the technique employed. 



The older observers were mostly content to regard the 

 Bacteria as enucleate — Monera, as Haeckel termed such 



' "Whilst occupying the British Association Table in 1908, under a 

 grant from the Goldsmiths" Company. 



