S TERIL IS ED PO TA TOES. 



59 



In the meantime, also, a series of knives, equal in number to the 

 potatoes to be used, must be prepared to divide the sterile potatoes, 



W. B . M 



Fig. 16. — Pink Torula growing on sterilised potato. The rose- 

 coloured pigment is contained within the cells of the growth, each of 

 which possesses a delicate yellow tint under the microscope. The 

 faint white film on the surface of the growth is due to an accidental 

 concomitant (a small bacillus). 



without at the same time in any way contaminating the cut surface. 

 For this purpose, ordinary kitchen knives are employed, without any 



Fig. 17. — Glass dish and bell for sterilised potatoes, 

 rim at the back of the blade, which can thus slip through the steamed 

 potato mass with but slight disturbance to it. A separate knife is to 



