Hie WorTi of Acidity in Cheese-malcing. 287 
cations of the butter-fat of the cheese which destroy its proper 
aroma and flavour, and substitute more or less offensive ones 
for them. 
The second effect of acidity in cheese-making alluded to 
above, but to which it is only possible to make a passing reference 
here, is the influence which it exerts in favouring the develop- 
ment of the mould on which the successful manufacture of soft 
cheese of the Camembert type, or of semi-hard cheese of the Stilton 
and Gorgonzola type, depend. A certain degree of acidity ajD- 
pears to be highly conducive, if not essential, to the growth of 
the fungus (PeniciUivrn) of which this mould consists, and whicli 
probably flourishes at the expense of the acid. Hence in both 
of these types of cheese, whether the mould grows outside the 
cheese or inside it, its production is favoured by not checking 
the acidity too much by salting or by cooling of the cheese in 
its earlier stages. 
The general outline of the work ot acidity in cheese-making 
which has been thus given, with an incompleteness of detail for 
which the unavoidable limitation of space must be some apology, 
will, it is hoped, at least offer a clue to the intelligent cheese- 
maker by which he will be enabled to work out for himself the 
rules that are necessary to enable him to avail himself of it for 
his own practical purjx)ses. Two conditions only are essential 
to his doing this : the first is that he shall possess some appliance 
for measuring acidity ; and the second is that he shall take some 
little trouble to learn how to use it properly. "With such an 
appliance at his command and with a few ordinary vessels, such 
as teacups or breakfast- cups, for holding samples of mUk, small 
quantities of solutions of rennet and of lactic acid, and a chamber 
of any kind in which the temperature can be maintained at from 
80° to 100° F.,he may without difiiculty institute a series of ex- 
periments similar to those described above, by which he will 
soon learn more than he would by reading pages of written de- 
scription. He may in this way study for himself the relative 
effects not only of acidity, but of rennet and of temperature, on 
the formation of the curd ; and it is not too much to say that 
unless he will do this he will never become a truly intelligent 
cheese-maker : for it is only in this way that he can disentangle 
the complex problem which is presented by the combined action 
of these three agencies on the casein of milk, 
Francis T. Boxd. 
