CHEMISTRY. 513 



to prevent decompositioii oi the chlorophyll by light. The extractiou 

 with alcohol was repeated aud the united solutions were coucentrated 

 and saponified. This saponification was carried out thus : The alcoholic 

 extract was treated with a moderate quantity of caustic-soda solution (1 

 part NaHO to 5 H2O) at a boiling temperature. The alcohol is evaporated 

 by degrees, water is added, and the soa]) separated by the aid of sodium 

 chloride, the soap precipitating in granular form. It is then shaken in 

 a separating funnel with petroleum ether, which assumes a dark-yellow 

 color, since it removes only the yellow constituent. On evaporating the 

 ethereal solution the yellow constituent remains; it crystallizes in dark- 

 yellow needles and gives all the chemical and spectrum reactions of a 

 lipochrome. 



The soap is next treated with ether, which removes various impuri- 

 ties, and then with a mixture of alcohol and ether, which removes the 

 f/ree/i constituent ; aud this, after purification, crystallizes in "sphajro- 

 crystals" of great beauty. From 450 grams dried wheat-leaves Hansen 

 obtained 3 to 4 grams solid coloring matter. 



In the solid state chlorophyll green is opaque aud does not fluoresce; 

 in solution it possesses a red fluorescence. 



Chlorophyll yellow occurs in small proportion as compared with chloro- 

 phyll green (1 : 100). Its solutions show no fluorescence. It possesses 

 the reactions of Krukeuberg's lipochromes, viz, a blue coloration with 

 sulphuric acid, the same with nitric acid, and a green-blue with a mix- 

 ture of iodine in potassium iodide. It shows three bands in the blue 

 half of the spectrum, but no absorption of red. 



Chlorophyll green has four bands in the red half of the spectrum, 

 agreeing with the four bauds of the ordinary chlorophyll solutions. (C 

 A. Tildc Munn, in Nature, xxx, 224; condensed from Hansen's Der Clilo- 

 rophyllfarbstoffj Abeiten des botan. Institute zu Wiirzburg, Vol. HI, Heft 

 \ , iind Sitzimgsbenchte der physik-medeoin. Gesellschafl, Wiirzburg, 1883.) 



Compbsition and Methods of Analysis of Human Milk, by Dr. Albert E. 

 Leeds. — In this comprehensive memoir the author gives results of the 

 examination of eighty samples of human milk. After a careful study 

 of many methods of analysis, he greatly prefers that devised by Ritt- 

 hausen and modified by Gerber, the main points of which are as follows: 

 (1) The total solids are determined by evaporating 5 grams in a plati- 

 num capside, after coagulating with absolute alcohol. (2) ^«/i ; The 

 residue is ignited gently and then to a dull-red heat. (3) The albumi- 

 noids are precipitated by sulphate of copper solution, with the addition 

 of sufficient potassium hydroxide solution to exactly neutralize the ex- 

 cess of the sulphate. (4) The precii)itate is separated by filtration, with 

 due precautions, and treated with ether to extract fat; the residue, 

 dried at 110<^ (less the weight of ash), gives the amount of albuminoids. 

 (5) The filtrate from the albuminoids, with washings, is used for the 

 determination of milk-sugar by Fehling's solution. Kesults are very 

 satisfactory. 



S. Mis. 33-^— ;« 



