610 REPORT— 1903. 



structural unit remains the cell, despite the modifications the cell necessarily under- 

 goes as a fixed element in the various tissues and organs. All phases of animal 

 and plant life are demonstrably of cellular origin and organisation, and their vital 

 manifestations represent the summed-up activities of cells. Every vital problem 

 therefore is ultimately a cellular problem, and a direct study of the cell, in so far 

 as may be possible, is the keynote of the problem it is desired to investigate. 

 A histological technique, aided by the microscope, will naturally be employed 

 vsrhere it is desired to study the relations of parts and the structural organisation 

 of the tissues and their cellular elements. The soluble products of the living cell 

 spontaneously present themselves for examination by chemical and other means. 

 It is otherwise with regard to the agencies acting and the processes occurring 

 within the confines of the cell. These are naturally beyond the range of the 

 ordinary methods of observation. The essential processes of life are intra-cellular 

 and intimately bound up with the living substance of the cell, and of these but 

 few data are possessed. The importance of the problems involved is as great as 

 their investigation is difficult. The cell exercises its vital functions in virtue of a 

 specific physical and chemical organisation of its molecular constituents. The 

 ordinary methods of biological and chemical research modify or destroy this 

 organisation, and do not admit of an intimate study of the normal cell constituents. 

 For this purpose it is essential to eliminate or to reduce to a minimum the influence 

 of external modifying agents on the cell or its immediate products. An intra- 

 cellular physiology can only be based on a direct study of intra-cellular consti- 

 tuents apart from their secretions and products. This, under ordinary circum- 

 stances, is impossible, with respect to actively functionating and intact cells. It 

 is obvious, therefore, that the first desideratum is a suitable method of obtaining 

 the cell plasma for experimental purposes, and it is only recently that this has 

 been successfully accomplished. The most feasible means of procedure appeared 

 to be the use of mechanical agents which, whilst bringing the cell substance 

 •within the field of observation, would at the same time be least likely to 

 affect its character and constitution. The method consists in a mechanical rupture 

 of the cells and the release of their contents under conditions favouring the 

 conservation of their properties. The first successful application of this descrip- 

 tion of method was made by Buchner in the particular instance of the yeast cell, 

 and with brilliant results. The researches of Buchner were of wide biological 

 significance, and were suggestive of much more than a cell-free alcoholic fermen- 

 tation of sugars. They demonstrated the possibilities of the new methods with 

 regard to more general vital problems. The Buchner process consisted in a 

 mechanical trituration of the yeast cell with the aid of sand, and a subsequent 

 filtration of the resultant mass under pressure through Kieselguhr. The filtrate 

 contained the expressed constituents of the yeast cell which were capable of 

 passing through Kieselguhr, and the product in virtue of its fermentative properties 

 was termed 'Zymase.' 



The writer and his colleagues have during the past four years been engaged in 

 investigating the application of cognate methods to biological research. The 

 advice and help generously aS"orded by Professor James Dewar materially 

 forwarded the progress of the research. 



It was considered that by the employment of low temperatures a disintegra- 

 tion of living cells might possibly be accomplished, and a wide field of inquiry 

 opened to investigation in the biological laboratory. For this purpose the methods 

 of mechanical trituration required refinement in several directions. 



The conditions it was desired to fulfil were, a rapid disintegration of the fresh 

 tissues and cells, au avoidance of heat and other modifying agents during the 

 process, and an immediate manifestation of the cellular juices obtained. 



It had likewise been noticed that ordinary filter pressing through Kieselguhr 

 removed physiologically active substances from the cell juices. Liquid air appeared 

 to be the most convenient means of obtaining the necessary cold, and it presented 

 the advantage of a fluid freezing medium, in which the material to be manipulated 

 could be directly immersed. The temperatare of this reagent (about -190°C.) 

 would in addition prevent heat and chemical changes, whilst reducing the cells 



