56 



Mr. S. Lea. 



[Nov. 22, 



rities at Kew that the fruit of Puneeria* coagulans, a shrub common 

 in Afghanistan and Northern India, possesses the properties of coagu- 

 lating milk ;" and experiments showed that an aqueous extract of the 

 seed-capsules of the above plant does somewhat rapidly coagulate 

 milk. 



I was recently requested to make some experiments on the seeds of 

 Withania to determine whether they contain a definite ferment with 

 the properties of ordinary rennet, and the applicability of such a 

 ferment to cheese-making purposes. 



The material supplied to me consisted of an agglomerated dry mass 

 of seed-capsules and fragments of the stalks of the plant. When 

 crushed in a mortar the whole crumbled down into a coarse powder, 

 in which the seeds were for the most part liberated from the capsules. 

 I picked out the larger pieces of stalk, sifted out the finer particles, 

 chiefly earth and fragments of the capsules, and then by a further 

 sifting I separated the seeds from the other larger particles. The 

 seeds appeared to be each enveloped in a coating of resinous material, 

 presumably the dried juice of the capsules in which they had 

 ripened. 



Taking equal weights of the seeds, I extracted them for twenty- 

 four hours with equal volumes of (i) water, (ii) 5 per cent, sodic 

 chloride, (iii) 2 per cent, hydrochloric acid, (iv) 3 per cent, sodic 

 carbonate. Equal volumes of each of the above were added in an 

 acid, alkaline, and neutral condition, to equal volumes of milk, and 

 heated in a water-bath at 38° C. The milk was rapidly coagulated by 

 the salt and sodic carbonate extracts, much less rapidly by the other 

 two ; of the four, the salt extract was far the most rapid in its action. 

 All subsequent experiments have shown that a 5 per cent, solution of 

 sodic chloride is the most efficient in the extraction of the active 

 principle from the seeds. 



There is no doftibt that the substance which possesses the coagu- 

 lating power is a ferment closely resembling animal rennet. 



I. A portion of the 5 per cent, sodic chloride extract loses its 

 activity if boiled for a minute or two. 



II. The active principle is soluble in glycerine, and can be extracted 

 from the seeds by this means ; the extract possesses strong coagu- 

 lating powers even in small amounts. 



III. Alcohol precipitates the ferment body from its solutions ; and 

 the precipitate, after washing with alcohol, may be dissolved up again 

 without having lost its coagulating powers. 



IV. The active principle of the seeds will cause the coagulation of 

 milk when present in very small quantities, the addition of more of 

 the ferment simply increasing the rapidity of the change. 



* Tlie genus Puneeria is now reduced by botanists to Witliania. 



