432 



of fat, or in other words as if the whole milk secretion was more or 

 les.s controlled by the secretion of fat. He says that if the facts indi- 

 cated by this experiment should be confirmed by future investigation, 

 the attempts at improvement in the milking qualities by intensive 

 feeding, breeding, selection of individuals, etc., might reasonably be 

 expected to haveau effect bothon the quantity of milk and onits richness 

 in fat. Further, the fact long believed to be true in practice, that in 

 general it is possible by increasing the amount of food nutrients to 

 make the milk of cows richer in fat, absolutely as well as relatively, 

 would seem to be fully confirmed. From this it would follow that in 

 the case of good cows rations far in excess of the normal rations at pres- 

 ent deemed sufficient could be used with good returns. 



The action of water on lead pipes, J. H. Garret {VII Intern. 

 Congress for ffi/i/iene and Vemof/raphy, London ; abs.in chem. Centralbl,, 

 1891, part 2, p. 720.) — It is stated that previous to being dissolved, the 

 lead in lead pipes used for conducting water is oxidized. This oxidation 

 takes place either through the oxygen dissolved in the water ; or through 

 the combined oxygen of the water which is freed by the action of the 

 lead; or by the presence of other metals, in consequence of electrolytic 

 processes; or, and principally it is believed, by the reduction of the 

 nitrates contained in the water. The nitrites by oxidation to nitrates 

 serve as an oxidizing medium, and by access of air provide for the 

 continuous solution of the lead. Alkaline water containing carbonates 

 acts only on new lead pipe, because a layer, i>robably consisting of a 

 basic carbonate of lea<l, is soon formed, which protects the i)ipe from 

 action, Phosi)hates and silicates are also said to favor the formation 

 of a protecting coating. As to the part played by C02 in water con- 

 ducted in lead pipes, it is explained that the CO2 first causes a solution of 

 the lead as carlxinate, and by the action of PbO on this carbonate an 

 insoluble basic carbonate results, which forms a protective coating on 

 the inside of the pii)es. The action of water on lead differs with the 

 temperature, being greatest at 50^ C. (122° F.). 



