2 14 PLANT LIFE. 



flasks a single cell, and a colony will form which can 

 be easily seen in two days' time. If further accuracy 

 is needed a mixture of wort and gelatine is made, and 

 a very small quantity spread out on a covered glass, 

 marked with squares : this is placed over a glass ring 

 and the cells examined, and their position marked on a 

 diagram. After leaving a short time (a day or so), the 

 cover glass is again examined, and the cells are seen to 

 have formed little colonies, which can be drawn off by 

 the point of a needle and plunged in a flask of wort. 

 They will then multiply in this until they can be 

 removed to a larger one, and eventually will be 

 numerous enough to supply a brewery. These races 

 show considerable differences in their method of work, 

 and in the energy of their budding, and of the 

 fermentation they produce ; and the most useful ones 

 are chosen. 



Under certain circumstances the yeast cells form 

 spores of the shapes figured below. A drop or two of 

 water and a small block of plaster of Paris are placed 

 in the lower glass shell ; then a drop of the yeast 

 sediment is put on the block and the upper shell is 

 placed over the under one. The air within is kept 

 moist by the drop of water, and under the influence of 

 the air the yeast cells will form spores. These vary in 

 appearance and number, and the cultivated and wild 

 races can generally be distinguished by the difference 

 in the spores. 



There are, as stated, different yeasts in almost every 

 brewery, every vineyard, and every distillery, and the 

 exact method of treatment also varies. Those found 

 in hot countries and used for making millet beer, rice 

 beer, etc., are also distinct. The bread yeasts are not 

 thoroughly understood, but apparently differ from those 



