CHEMICAL SCIENCE. 267 



this state, and after desiccation, they were examined. Their consistence 

 was always superior to that of the tissue itself; the washings had not 

 perceptibly dissolved the elements of the blood. We then detached with 

 the scissors some of these stains, which we reduced into small strips, 

 which were suspended in distilled water. After long immersion the 

 liquid was not colored, and agitation did not develop in it any streak 

 which could render evident the solution of a body of greater consistency 

 than the liquid employed. The application of heat did not determine any 

 opalescence indicating the solution of the least trace of albumen. 



The course to be followed for indicating the existence of this organic 

 liquid coagulated on the tissue, owing to the washing performed by the 

 criminal, consists in putting the stains in contact with a weak solution of 

 pure potassa ; and, after reacting for some time, a liquor is obtained, which 

 is precipitated white with nitric acid or with pure hydrochloric acid, 

 which indicates the solution of one or more of the matters of the blood. 

 By this alkaline treatment the stain loses some of its color, but what then 

 is the body which is found in some measure indelibly fixed on the tissue ? 

 To solte this question, it is only necessary to put the stained tissue in 

 contact with pure hydrochloric acid, which dissolves the matter of the 

 stain, and forms a solution which, carefully reduced to dry ness, furnishes 

 a residue having the property of acquiring a very clear blue color, with 

 ferro-cyanide of potassium, and a blood-red color, with sulpho-cyanide of 

 potassium. These characters evidently demonstrate in washed blood- 

 stains the presence of iron, which is always present in the blood. From 

 the foregoing, when the chemist is enabled to establish in washed blood- 

 stains the simultaneous existence of iron and a proteic element of the 

 blood, it furnishes to the prosecution a new element of proof of guilt. 

 Jour, de Chtmie Medical. 



METHOD OF EXAMINING BUTTER. 



The method of examining butter here described is only of use for the 

 determination of its commercial value ; it is calculated to enable a com- 

 parison of several samples of butter to be effected in a short time. The 

 following instruments are required : 



1. For measuring the butter, a cylindrical glass tube, about two and 

 one-half inches long and two lines wide, and open at both ends, is em- 

 ployed. It is ground in a conical form at one end, and flat at the other. 

 Into this is passed a cork, attached to an iron wire, which closes the tube 

 almost air-tight, but can be readily pushed through it. When in use, the 

 cork is drawn back to the flat end of the tube, which is then filled by 

 sticking it into a mass of butter ; care must be taken to prevent the intru- 

 sion of air between the portions of butter. A mark is made on the tube, 

 to indicate the quantity of butter to be employed in the examination. 



2. A graduated tube, five and one-half inches long, two and one-half 

 lines wide, closed at one end, and ground off at the other, is divided at the 



