342 THE dairyman's majtual. 



of ill-conditioned rennet, and this should be carefully 

 guarded against. It is always a safe precaution, when 

 doubt exists as to the purity of the rennet, to filter it 

 through flannel or even through cotton fiber or blotiing 

 paper. By varying the character of the rennet the cliar- 

 acter of tlie cheese may be changed, and where many 

 varieties of fancy cheese are made the rennet used differs 

 ,very much. Some very celebrated French cheeses are 

 made of rennet prepared with water to which brandy is 

 added in the proportion of one-third, and spices and 

 aromatic herbs are steeped with the stomachs in this 

 mixture. For other cheeses pig's bladder is steei^ed in 

 wliite wine and vinegar, and others again are made with 

 diluted acids only. 



The exhausted stomachs need not be thrown away, 

 but may be again salted and left to renew their strength. 

 This they will do in the course of some months, and as 

 yet no one has been able to say when this power of re- 

 covering their activity will be entirely lost. If this 

 activity depends upon, or belongs to, the membrane, as 

 almost conclusively appears, it may last until tiie mem- 

 brane itself is dissolved away. 



It has been stated that a certain quantity of the liquid 

 rennet is sufficient to produce a certain effect upon a 

 given quantity of milk at a stated temperature. If one of 

 these elements of the process is varied, the others are sub- 

 ject to a proportionate change. Thus if the temperature 

 is higher the time is reduced ; if the quantity of rennet is 

 increased the time is lessened. At a lower temperature 

 more rennet is required or more time must be given. 

 These nice calculations must be based upon the normal 

 conditions given as well as ujDon the quality and strength 

 of the rennet ; and these vary as the age of the dried 

 stomachs or the mode of preparing, the solution. A 

 standard preparation of rennet is made for use in the 

 dairy, and the dairyman will be able to make his calcula- 



