FAT GLOBULES. O 



cream and butter, and therefore presumably in milk ; he proves 

 its existence, and, in fact, isolates it, by washing cream with 

 water and separating the layer of globules till milk-sugar, casein, 

 etc., are all removed. 



(2) On the behaviour of milk with ether ; his experience 

 differs from that of Bechamp, as, while the latter finds that 

 ether expands the globules to several times their normal size, 

 Storch states that they are not swollen. 



(3) On the appearance of the fat globules under the micro- 

 scope when the milk has been stained by ammoniacal picro- 

 carmine, and the layer of cream treated with successive quan- 

 tities of water till all the milk-sugar has been removed ; he 

 notices that a stained layer is present round each fat globule. 



There is much to be said in favour of Storch's reasoning, and 

 other evidence may be adduced in favour of it. Butter, in 

 which the globules are certainly more naked than in milk, can 

 be prepared with about 85 to 86 per cent, of fat ; this is solid, 

 because the solid fat globules are in close proximity ; cream, on 

 the other hand, cannot be prepared with more than about 72 per 

 cent, of fat, and as this has the same consistency as butter at 

 the same temperature, it may be assumed that the globules are 

 in equally close proximity. This would agree with the view 

 that each globule was surrounded by a layer, which increased 

 the effective size. Storch himself has, however, shown that the 

 fat in butter does not exist in the form of globules, but as a nearly 

 homogeneous mass, containing water globules. Storch has 

 adduced evidence, based on the property of ether to emulsify 

 this mucoid substance, that butter-milk contains a larger amount 

 than milk, and on this has deduced a theory that churning 

 consists of rubbing off the membrane, with the effect that the 

 globules coalesce. The author has proved experimentally the 

 fact that buttermilk is richer in mucoid substance than milk by 

 separating it with a cream separator. Storch considers this as 

 confirmatory evidence of the presence of a membrane. 



The evidence is, however, inadequate to settle the question, 

 and in some respects may be held to show that a membrane does 

 not exist. As the author has succeeded in isolating the protein, 

 he has no doubt of its existence ; by estimating in butter and 

 buttermilk the water, fat, milk-sugar, protein, and ash, Storch 

 finds that there is much less milk-sugar and more protein in 

 proportion to the water in butter than in buttermilk ; he cal- 

 culates the proportion of protein and water equivalent to the 

 milk-sugar in butter on the supposition that the milk-sugar is an 

 index of the buttermilk left in the butter, and finds a residue 

 of the following percentage composition in three series of ex- 

 periments (see Table I.). 



