554 VITAL ACTIONS OF THE LOWER FUNGI, 



the result of its action there is at first a complete 

 combustion, and therewith a production of active energy 

 which suffices for the functional activity of the organism. 

 The most various groups of atoms fall a prey to the 

 oxidising action of the oxygen, nevertheless it is chiefly 

 those which have been formed in the protoplasm as the 

 result of the intra-molecular respiration, and which are 

 more easily attacked by the oxygen than the materials 

 which are taken up by the food and formed by the 

 process of assimilation. The absorption of oxygen, and 

 the respiration by means of oxygen, go hand in hand 

 with the energy of the decomposition which takes 

 place in the protoplasm, and therefore with the 

 activity of assimilation and growth, and thus they 

 render a large amount of energy available for the active 

 tissue change. External influences, especially the pres- 

 sure of oxygen in the surrounding medium, appeal- 

 relatively indifferent as compared with the powerful 

 influence of the protoplasm ; it is only the temperature 

 of the nutrient materials which seems to exert a more 

 marked influence on the amount of respiration, but it 

 acts only by influencing the protoplasm and the decom- 

 position occurring in it. In the case of the higher 

 plants, it has been found that as the temperature rises, 

 the extent of the respiratory process continually increases 

 in such a manner that its curve rises from zero until 

 the temperature at which death occurs is almost reached, 

 and then it suddenly falls to zero . Whether a similar law 

 holds good in the case of the micro-organisms is not yet 

 known, but it is, a priori, probable. 



Tissue change jf OXV g en j s absent, decomposition in the protoplasm 

 is absent. still continues for some time, as has been ascertained 

 by investigations on higher plants, and more especially 

 on fruits, but the tissue change differs both as regards 

 its products and its energy. Atomic combinations 

 which would otherwise at once enter into union with 

 oxygen, either remain unaltered after they are once 

 formed, or enter into combinations with other bodies, so 

 that all sorts of products result, which are not observed 

 when plenty of oxygen is present. Carbonic acid and 



