CHAPTER V. 



THE LIVING SUBSTANCE OF PLANTS CONCLUDED. 



III. PROTOPLASM ix A FUNGUS: MUCOR. 



NOTE. Omit or read this chapter, or where there is time, if the teacher so 

 desires, it may be studied in addition to spirogyra, or as an alternate if spiro- 

 gyra cannot be obtained. 



Demonstration 8. 



48. To obtain the black mould. If stock cultures of the black mould 

 are not at hand it is well for the teacher to make some preparation several 

 weeks beforehand for securing the mould for the cultures. 



To do this take an orange or lemon, cut in halves, and squeeze out the 

 juice. Let it lie exposed in the room for a day. Then place this with some 

 old bread in a moist chamber and set aside in a warm room for several days. 

 In this time several moulds will appear. Some may have a blue color, others 

 white, and some will probably become black. The black one is quite likely 

 to be the black mould. New cultures of the black mould should now be made 

 on fresh bread, or on the cut surface of baked potatoes. If they are made on 

 potatoes the following method will answer; if on bread put the pieces in a 

 moist chamber and sow the spores as described here for the potato cultures. 



Demonstration 9. 



49. To make cultures of the black mould. Take some freshly baked 

 potatoes. Make a cut about \cm deep entirely around them. Break them 

 into halves and place these in moist chambers on damp paper with the cut 

 surfaces uppermost. If a platinum needle which can be flamed is not at hand, 

 take a dissecting needle, thrust it for a moment into strong alcohol. Hold it 

 in the air until it is dry. Touch the moist surface of the potato with the 

 needle, then touch the black heads of the fungus on the bread or fruit to catch 

 some of the spores. Then touch the potato surface again, repeating this sev- 

 eral times until spores have been put in a number of spots. ' Close the moist 



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