NUTRITION. 221 



to say, from the potential chemical energy of the 

 compounds which form its medium of culture, we 

 then find ourselves in the worst possible situation for 

 the recognition of organic destruction. Further, it is 

 doubly wrong to assert that in so ill-chosen a type 

 the functional phenomena do not result from an 

 organic destruction for at first there are no very 

 distinct functional phenomena here and, in the second 

 place, there certainly is organic destruction. The 

 phenomena of the morphogenic vitality detected in 

 the yeast are the exact concomitants, or the results, 

 of the destruction of an organic compound, which in 

 this case is sugar. The yeast destroys an immediate 

 principle, and this is the point of departure of its vital 

 manifestations ; only, it has not, as a preliminary, 

 clearly incorporated and assimilated this principle. 

 When, therefore, the functional phenomena are 

 effaced and disappear, we none the less find pheno- 

 mena of destruction of organic compounds which are 

 in a measure, a preface to the phenomena of growth. 

 This is what happens in the case of brewers' yeast : 

 and here, again, the two categories of facts exist 

 Once more, we find, in the first place, the phenomena 

 of destruction (destruction of sugar, reduced by 

 simplification to alcohol and carbonic acid) pheno- 

 mena which this time no longer respond to obvious 

 functional manifestations ; and, in the second place, 

 the phenomena of chemical and organogenic synthesis, 

 corresponding to the growth of the yeast and the 

 multiplication of its protoplasm. The former are no 

 longer detected, as we have just said, by striking 

 manifestations. However, it is not true that every- 

 thing which is visible and which may be isolated 

 outside the activity of the yeast is part of those 



