310 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



easily give rise to incorrect conclusions in regard to the internal 

 structure of such a delicate organism as the yeast cell. It would al- 

 most appear, in fact, that we have gone as far as it is possible to go 

 in this direction, and some improved method of inA^estigation will 

 have to he resorted to if many of tlie questions which are at present 

 in doubt are to b;- satisfactorily solved. It is possible, for instance, 

 that a very careful microscopical study of the unstained cell by means 

 of ultra-violet light may be helpful in giving us a better insight into 

 its internal structure, and Mr. Barnard has already caiTied out some 

 interesting experiments of a preliminary character in this direction. 



When one remembers that the whole of a miniature solar system 

 is comprised within the compass of an atom, it is not, perhaps, alto- 

 gether fanciful to suppose that the yeast cell — small as it is — may 

 have a much more highly d 'veloped internal organization than has 

 been revealed with our present imperfect means of investigation, and 

 that there may be more or less distinct localization of the different 

 functions of the cell. In this connection two sets of facts may be 

 briefly referred to. 



In the fii-st place, it is well known that the yeast cell, like other 

 living organisms, may be made to perform different functions accord- 

 ing to the conditions under which it is compelled to carry out its 

 activities. Thus, whilst the ordinary Scvccharomyces cerevisioi nor- 

 mally decomposes sugar with the production of alcohol and carbon 

 dioxide, and only about 3 per cent of glycerine, it has been found that 

 when the fermentation is conducted in the presence of a considerable 

 quantity of sodium sulphite the main products of the fermentation 

 consist of acetaldehyde and gl3'cerine in roughly equal molecular 

 projiortions, and that instead of the normal 3 per cent as much as 36 

 per cent of glycerine can be produced. In other words, it would 

 appear that the well-known equation representing fermentation, 

 viz : 



CeH,,Oe = 2C,HeO + 2CO2 

 alcohol 



has, when the process is carried out in the presence of sulphite, to 

 be written in the following very different and unfamiliar form, 



C,Hi20„=CH,COH-fCO,+C,H,03 



acetaldehyde glycerine 



In the next place, it is of considerable interest to note that the 

 behavior of the enzymes within the cell appears to differ materially 

 from that of the same enzymes in the expressed juice. Thus, the 



