590 



made by Buchner's method, no oxygen consumption is to be detected. Similarly, 

 mechanical disintegration puts an end to the process. Now, although yeast juice, 

 as is well known, is still able to cause alcoholic fermentation, Warburg and 

 Meyerhof have shown that the activity of yeast cells in this respect is greatly 

 diminished by rubbing with sand. Similar observations on other cells were made 

 by Battelli and Stern, Palladin and others, to which reference will be found in 

 the article by Warburg (1914). 



Now cells can be killed by such treatment as dehydration with acetone, etc., 

 without obvious destruction of structure ; in fact, ordinary microscopic structure 

 is intact. Warburg points out (1914, p. 317) that acetone and ether make a 

 good fixing method for cells even of the delicacy of the eggs of the sea urchin in 

 division. The important point in the process, as used for the investigations with 

 which we are now concerned, seems to be the rapid drying. The chemical com- 

 position is practically unchanged, even the lipoids remain in the cells. The effect 

 of this treatment on yeast cells is greatly to diminish their fermentative power 

 (Buchner and Hahn, 1903, pp. 87 and 269). On bacteria (staphylococci), Warburg 

 and Meyerhof found that its effect on oxygen consumption and carbon dioxide 

 production was not to abolish them completely, although they were greatly 

 diminished. Under favourable conditions, this respiratory process might remain 

 constant for some hours, with a respiratory quotient of 0'65 to 0'9. The injury to 

 the oxidation process was, in fact, less than to the fermentative power of yeast 

 by similar treatment. Of course, in such experiments, it is essential to know that 

 all the cells were " killed," that is, incapable of growth. To do this, after drying 

 with acetone, they were heated to 100, and shown to be sterile after the experi- 

 ment was concluded. If treated with acetone alone, without heating, the oxygen 

 consumption falls only to one-third of the normal, although cultures showed that 

 nearly all the cells were killed. In absolute amount, the oxygen consumption of 

 such completely sterile cells does not fall much below that of some other normal 

 surviving cells, those of the liver consuming 2 '7 c.c. of oxygen per gram per hour, 

 while the sterile staphylococci consumed 1-5 c.c. 



If we compare these results with those on the eggs of the sea urchin, we find 

 some instructive facts. The unfertilised eggs, rubbed with sand, show at first a 

 nearly normal oxygen consumption ; this slowly decreases, so that in the third hour 

 it is only one-quarter to one-third of the normal. Fertilised eggs, already 

 divided, have, along with their more developed organisation, a greater consumption 

 of oxygen than unfertilised ones. Moreover, on rubbing with sand, the decrease is 

 greater, so that in thejlrst hour it only amounts to one-quarter to one-third of the 

 normal. Acetone-dried unfertilised eggs also have a measurable oxygen con- 

 sumption, although it is less than when they are simply rubbed with sand. 



In order to obtain some further idea as to what is to be understood by cell 

 structure, Warburg (1914, p. 315) calls attention to the fact that in the muscle cell 

 a much larger proportion of the chemical energy appears as free energy, useful for 

 doing work, than if the cell is disintegrated ; in the latter case the chemical energy 

 obtained from oxidation processes is all degraded to heat. By cell structure, then, 

 we mean those elements with which, or by whose aid, the work of the cell is 

 carried on. They are arrangements by which the chemical energy of the oxidation 

 processes is caught, as it were, before it has fallen to the state of heat. If we look 

 upon the cell constituents as chemical compounds merely, without the assistance of 

 some mechanism, nothing but heat could be obtained on oxidation. The same 

 thing applies to a petrol motor with its fuel. If smashed up and mixed together, 

 nothing but heat would be obtained by burning the mass. 



If we divide up a cell nucleus into a thousand particles and consider them 

 distributed throughout the cell, the nuclear structure is destroyed, as shown 

 by the fact that the ordered movement shown in karyokinesis is no longer 

 possible. 



As remarked above, the- cell membrane is to be regarded as a very important 

 element of the cell structure or mechanism. 



We see then that the oxidations effected by the aid of the enzyme mechanisms, 

 treated of in the earlier parts of the present chapter, take place in the cell in the 



