182 ABOUT FUNGI. [CHAP. 



fungi, for we have seen (Chapter II. ante) that plants 

 possessing chlorophyll give off oxygen. 



Fungi are essentially either parasites or scaven- 

 gers, or both. We have seen (Chapter II.) that 

 green plants have the power of constructing protein 

 out of a few elementary substances. Not so fungi ; 

 their food must be organised, that is, the elementary 

 substances must be chemically combined to form a 

 part of some previously existing animal or plant. 

 Thus sugar is a vegetable product which consists of 

 the chemical elements Carbon, Hydrogen, and Oxy- 

 gen. Torula can grow and flourish in a solution of 

 sugar and water, though it cannot live in a mixture 

 of Carbon, Hydrogen, and Oxygen, unless they have 

 been elaborated into a compound by being taken into 

 the vegetable economy. 



The reproduction of Torula is effected in the 

 simplest manner possible. It either develops trans- 

 verse partitions across the cell and thus divides itself 

 into two or more cells ; or, what is more common, it 

 produces a swelling or bud at some point outside the 

 cell-wall, and this bud grows into a full-sized cell 

 identical in every respect with that from which it 

 originated. Fig. 134, B, shows how this process of 

 budding goes on. 



All fungi are composed of cells similar in every 

 respect to Torula, though in the higher species these 

 cells are combined in a variety of ways to produce 

 forms varying greatly from each other. As an ad- 

 vance in organisation upon Torula we have Peni- 

 cillinm (fig. 135). Here we have simply a number of 

 cells like Torula, a little drawn out and placed end 



