HOW TO GROW SOME COMMON MOULDS 223 



moulds are sure to lie. The bread should then be placed in a soup 

 plate and covered either with a tumbler of glass or another soup 

 plate. 



In all probability white moulds — some species of mucor — will 

 first appear, and following upon these, and when a good deal of the 

 moisture has been abstracted from the bread, blue green moulds- 

 species of peniciHum, and olive green moulds — species of eurotium. 



If a more minute stud}' of moulds is intended it is well to obtain 

 a pure culture, and for this purjDose the sterilization of both 

 material and apparatus is necessary. 



The bread should be baked in an oven until nfcely- toasted, and 

 in this wa\^ all spores will be killed. Then a few of the spores for 

 special study, and of one kind of mould only, shoiild be transferred 

 on a needle, whose point has been passed through a flame, from a 

 piece of mouldy bread to the toasted bread, which shoiild be slightly 

 moistened. In order to exclude all other strange spores, the cul 

 tiire should be put in test tubes which have been sterilized and 

 scalded. 



To sterilize the test tubes, place a number of them in a jam jar 

 or beaker, put the latter in a sauce pan of water, and keep it boiling 

 for one hour. Then put pieces of bread, potato, fruit or vegetable, 

 to which spores have been transferred, into the tubes and scald 

 them. 



If it is desired to watch the progress of the growth of the spores, 

 they can be grown on some transparent medium — apple jelly pro- 

 duces good results — placed in a small shallow glass dish covered 

 with a tight fitting glass lid. 



Although at first one may not succeed in obtaining an absolutely 

 pure culture, yet it is certain that where care has been taken, the 

 indi\-idual plants of the particular culture will far outnumber all 

 others. 



For more detailed instruction in this subject, readers are referred 

 to leaflet No. 17, written by Mr. Tabor, and obtainable from the 

 General Secretary. 



From. School N attire Study, Feb., '13, London, Eng. 



