THE FUNGUS, OR COLORLESS PLANT. 25 



if, when yon touch it with a lighted match, it burns 

 with a blue flame. But you must be careful in making 

 this experiment, as the internal-revenue officer might 

 arrest you for illicit distillation. I advise you never 

 to drink the alcohol which you or anybody else may 

 distill, because it is very injurious. Now I have told 

 you the torula grows ; it has life, but how does it grow 

 — as a mineral, a vegetable, or an animal ? Minerals 

 have a kind of growth, but the new matter which a 

 mineral adds to itself is placed externally, not internally. 

 The mineral grows larger and larger by additions made 

 to its outside, as the snowballs get larger and larger 

 when you roll them along the snow, or as candles be- 

 come thicker and thicker as they are dipped into the 

 melted tallow. This is called growth by accretion, 

 but the torula or yeast-cell grows by taking in new 

 substance in among the particles of its old substance, and 

 this kind of growth is called by a long name — intus- 

 susception. This is one of the reasons why it is not a 

 mineral : is it an animal ? The line that divides the 

 animal from the vegetable kingdom is not very well 

 marked, but there are two reasons why the torula is 

 not an animal. In the first place, its jelly or proto- 

 plasm is shut up in a close sac; you remember the 

 tough, woody cellulose that I compared to a ball-cover 

 is the sac, but the PROTOPLASM-jelly of animal cells 



2 



