12 CASEIN. 



The first treatment of the curd in cheesemaking is de- 

 signed to remove the enclosed whey, the curd being vigor- 

 ously stirred or broken by hand (with a curd breaker or 

 similar instrument). Curd mills are also used, consisting 

 principally of a grid or lattice of galvanised iron rods, between 

 which rotates a shaft armed with teeth. When the shaft is 

 turned by means of the handle, the curd introduced through 

 a feed hopper is pressed between the rods by the teeth, and 

 thoroughly broken up or squeezed. The broken curd is then 

 stirred to a uniform pulp with a little water in a large vat, 

 and passed through a sieve or mill, after which sufficient 

 water is added to form a milky liquid. This is left for the 

 curd to settle down, and sieved to drain off the liquid ; or in 

 large dairies is put through a centrifugal separator. 



All centrifugal machines are driven by steam or electricity, 

 by means of intermediate gearing, or else by special driving 

 mechanism, and have to be run at high speed, which in turn 

 entails solidity of construction. For reasons of safety, there- 

 fore, the regulation issued by the German Chemical Trades 

 Accident Insurance Association, to the effect that the maxi- 

 mum permissible load and rate of speed should be conspicu- 

 ously posted on each centrifugal machine, and machines of 

 this kind driven by attached motors should be provided with 

 a speed indicator marked with the maximum permitted speed, 

 is perfectly justified. These machines are either driven from 

 overhead, through a second motion mounted on uprights 

 forming part of the machine, or else from below, the motion 

 being transmitted to the vertical shaft, this latter method 

 being now almost exclusively employed. Though both sys- 

 tems entail good construction and very careful supervision in 

 working, this is particularly the case with overhead driving. 

 They also require very strong foundations, the contents of 

 the drum are very liable to contamination by the lubricating 

 oil, and the accessibility of the drum is greatly reduced by 



