THE CHEMISTRY OF COOKERY. 639 



differences, I suspect, are all due to the difficulty of isolating the sub- 

 stances in question, especially of the vegetable substance, which is so 

 intimately mixed with the starch, etc., in its natural condition that com- 

 plete separation is of questionable possibility. 



This will be understood by the following description of the method 

 of separation as given by Miller (" Elements of Chemistry," Vol. Ill) : 

 " Legumin is usually extracted from peas or from almonds, by digest- 

 ino- the pulp of the crushed seeds in warm water for two or three 

 hours. The undissolved portion is strained off by means of linen, and 

 the turbid liquid allowed to deposit the starch which it holds in sus- 

 pension ; it is then filtered and mixed with dilute acetic acid. A 

 white flocculent precipitate is thus formed, which must be collected on 

 a filter and washed." 



This is but a mechanical process, and its liability to A^ariation in 

 result will be learned by anybody who Avill repeat it, or who has sepa- 

 rated the gluten of flour by similar treatment. 



Practically regarded in relation to our present subject, casein and 

 leo-umin may be considered as the same. Their nutritive values are 

 equal and exceptionally high, supposing they can be digested and as- 

 similated. One is the most difficult of digestion of all the nutritive 

 constituents of vegetable food, and the other enjoys the same distinc- 

 tion among those of animal food. Both primarily exist in a soluble 

 form ; both are rendered solid and insoluble in water by the action of 

 acids ; both are precipitated as a curd hy rennet, and both are rendered 

 soluble after precipitation or are retained in their original soluble form 

 by the action of alkalies. They nearly resemble in flavor, and John 

 Chinaman makes actual cheese from peas and beans. 



These facts, coupled with what I have already said concerning 

 cheese and its cookery, will doubtless lead my readers to expect some- 

 thing concerning pease-pudding and potash in my next. 



XXXV. 



"Pease-pudding hot, pease-pudding cold, 

 Pease-pudding in the pot, nine days old." 



I leave to Mr. Clodd the historical problem of determining whether 

 this notable couplet is of Semitic, Aryan, Neolithic, or Palteolithic 

 origin. Regarded from ray point of view it expresses a culinary and 

 chemical principle of some importance, and indicates an ancient practice 

 that is worthy of revival. 



I have lately made some experiments on the ensilage of human 

 food, whereby the cellular tissue of the vegetable may be gradually 

 subjected to that breaking up of fiber described in No. 28. One of 

 the curious achievements of chemical metamorphoses that is often 

 quoted as a matter for wonderment is that of converting old rags into 

 sugar by treating them with acid. The wonderment of this is dimin- 

 ished, and its interest increased, when we remember that the cellulose 



