407 



men ; 7.40 per cent, to 6.90 per cent. ; 7.23 per cent, to 4.44 per cent. ; 

 and 6.54 per cent, to 6.40 per cent. Two samples with more than 

 6 per cent, of sokible matter had an acid reaction, while the others were 

 neutral. Professor Poleck believes this chemical change of the flour to 

 be induced by the fact that the barrel prevents communication with 

 the atmospheric air and the equalization of temperature. This view is 

 confirmed by the oft-repeated observation that flour in sacks keeps 

 fresh for a much longer time, and that the mustiness in barrels always 

 developes first, and exists in the highest degree in the center, viz, that 

 portion most remote from the outer air. 



Effect gf the food of cows on the composition of the 

 MILK. — A series of experiments prosecuted not long since in Germany 

 led to the conclusion that, contrary to. the usual impression on the sub- 

 ject, very considerable changes in the composition of food may be made 

 without inducing corresponding changes in the relative constituents of 

 the milk of thfe cow ; the only effect being in the amount of the con- 

 centration of the milk. To determine these results with accuracy. Dr. 

 Kuhn has repeated the experiments, w ith the general result of showing 

 that an increase in the albumen and fatty elements of a moderate diet 

 produces an increase in the milky yield, which gradually rises (along 

 with bodily condition) to a certain maximum, corresponding in each 

 case with "the maximum increase of the above elements. Sooner or 

 later, however, the natural diminution depending on the duration of 

 lactation occurs, and no increase can be produced by increasing the 

 food. Diminution of the above elements of the food causes a diminu- 

 tion in the milk yield. The addition of fat increases the ingredients of 

 milk generally, and has no special influence on the amount of fat in the 

 milk. The absolute production of the individual elements of the milk 

 agrees generally with the relative production of the milk as a whole, 

 (most regularly in the case of sugar.) The variations from this are 

 different for the different ingredients. 



In the percentage numbers, sugar does not seem to be affected by the 

 diet. The variations in the amount of albumen are so small as not to be 

 capable of determination. Xo influence on the amount of caseine could 

 be traced to the food. The influence of food on the amount of fat is 

 seen to be very small. When it appeared to be altered it was after in- 

 crease of the albuminiods of the food. Increase of the fatty elements 

 of the food did not specially affect the amount of butter ; the variations 

 in the percentage amount of caseine and fat are to be attributed to irreg- 

 ularities in the fat production in the gland. The farmer must therefore 

 not hope by variations in the food to produce a "butter-cow" or a 

 "cheese-cow." The differences in this respect are differences of stock 

 and individuals. 



Pith of woody matter. — Mr. A. Gres, in a recent memoir upon the 

 pith of woody plants, endeavors to show that this pith, in the dicotyle- 

 donous species, is not simple and uniform in its organization, as has 

 been supposed, but that it is capable of furnishing appreciable charac- 

 teristics for a natural classification. He finds that it preserves its vitality 

 for many years, sometimes even to a very advanced age, and that it con- 

 tains in one x)art or other of its cellules a supply of nutritive material in 

 the form of starch and tannin, which is taken up again at the moment 

 of the development of the new verdure in spring. He thinks, also, that 

 it participates with some of the tissues of the wood itself in the nutri- 

 tion of the plant, and thut it fills an important physiological place 



