THE LIVING SUBSTANCE OF PLANTS. 2$ 



chamber and set aside in a warm place. For several days observe the growth. 

 First there appear small spots of delicate white threads. This tuft of threads 

 increases in size, the threads elongate and branch. 



Demonstration 1O. 



50. To prepare the mycelium of the black mould for study of the proto- 

 plasm. These white threads of the mould are fungus threads. They are 

 called the mycelium. The mycelium is the vegetative or growing portion of 

 the mould, while the black heads are the fruiting portion. With a needle 

 carefully lift a small tuft of these threads grown in the moist chamber, place 

 them in a drop of water on the glass slip and carefully tease them apart so that 

 individual threads can be seen. Prepare for study under the microscope. 

 When the microscope has been focussed on a suitable group of threads each 

 pupil can then observe the things noted in paragraphs 51-53. 



51, Mycelium of the black mould. Under the microscope 

 we see only a small portion of the branched threads. There is 

 no chlorophyll as in spirogyra. This is one of the important 

 characters of the group of plants to which the black mould 

 belongs. In addition to the absence of chlorophyll, we see 

 that the mycelium is not divided at short intervals into cells ; 

 but appears like a delicate tube with branches, which become 

 successively smaller toward the ends. 



Fig. n. 

 Thread of mucor, showing protoplasm and vacuoles. 



52. Appearance of the protoplasm. Within the tube-like 

 thread now note the protoplasm. It has the same general 

 appearance as that which we noted in spirogyra. It is slimy, 

 or semi-fluid, partly hyaline, and partly granular, the granules 

 consisting of minute particles (the microtomes). While in 



