354 SCIENCE PROGRESS 



ordinary colloid structure. 1 It may be that further careful use 

 of the method will add to our knowledge of the behaviour of the 

 nucleus in the living state, but on account of its limitations 

 the method can never become a general one for the study of 

 nuclear cytology. 



These limitations are also an obstacle in the way of progress 

 by the method, in the extended study of the intimate physics 

 and constitution of the plant cell. As has been indicated, the 

 protoplasm is by no means constant in characters in the cases 

 which have been examined, so that for a logical study of cell 

 physiology in relation to the plant the component cells in ques- 

 tion must be examined. There is no doubt, however, that the 

 method has given us a further insight into the actual structure 

 of the living cell, and considering its comparatively recent 

 development these results are sufficient to establish it as an im- 

 portant method of research. Certain attributes of cell structure 

 must be of more or less general application, and along these lines 

 the results should be of great use. 



No attempt has been made in the present brief account to 

 discuss the problems which arise from considerations of the 

 results obtained. It has been rather desired to give in outline 

 the methods of practical application of the principle to botanical 

 work, and to state without any full discussion the main results 

 which have so far been achieved. In the study of colloids the 

 method is now an indispensable one, and undoubtedly it must 

 become so in researches into the behaviour of the colloid proto- 

 plast. 



1 v. Gaidukov ; also from unpublished work of the Author. 



