Photo: James's Press Agency. 



"THE CULLINAN DIAMOND' 



The largest diamond in the world, found in South Africa in 1905. Before it was cut it weighed a 

 pound and a half, and was about as large as the illustration. In the rough state it resembled a piece of ice 

 rather than a superb diamond. A diamond is the purest form of crystallised carbon. 





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Photo: J. J. Ward. 







THE YEAST PLANT (SACCHAROMYCES) 



The yeast-cell produces a ferment which changes sugar into 

 alcohol and carbon dioxide: or attacks the dough and not only 

 "raises "it by evolving the gas, but makes the bread more palat- 

 able and digestible, producing likewise a trace of alcohol. 

 There are several different kinds, e.g. the common cultivated 

 yeast of beer and bread, and the wine-yeast found wild on the 

 skin of grapes or in the vineyard soil. It was Pasteur who 

 proved that the yeast plant is the cause of the kinds of fermen- 

 tation referred to. Each ellipsoidal cell is a tiny, colourless 

 plant able to bud out others just like itself. In actual size each 

 is about 3 Vjo of an inch in its longer diameter. 



Photo: J. J. Ward. 



THE WINE- YEAST OR " CALIFORNIAN BEES" 



This so-called "Ginger-beer Plant " consists of various micro- 

 organisms, two of which, a yeast (Saccharomyccs pyroformis) 

 and a bacterium (Bacterium vermiforme), set up an alcoholic 

 fermentation in a sugar solution. 



