276 LECTURES TO SCIENCE TEACHERS. 



oxidation of the non- nitrogenous substances such as fat is 

 diminished, and the fat consequently accumulates. The 

 splitting up of the tissues, which we now know to be inde- 

 pendent of combustion, in all probability is carried on by 

 means of ferments in the same way as the splitting up of 

 food in the intestines. But here we reach the limit of our 

 knowledge, and must wait until further experiments sub- 

 stitute certainties for hypotheses, and enable us to talk, 

 not of probabilities but of facts. 



