lio THE AMERICAN MONTHLY [April 



finger also should be washed with some antiseptic, in 

 order to take every precaution against infection. This 

 method of obtaining the blood was used by us for the 

 three instruments. 



For introducing the blood into the chloroform-benzole 

 mixture, a pipette of fine calibre may be used. A suf- 

 ficient quantity of blood is drawn into this and expelled 

 in the middle of the mixture. Care should be taken that 

 all of the blood is not blown out, but that some remains 

 in the tip of the pipette. That which has been expelled 

 will usually adhere to the pipette as a large drop and 

 must be shaken loose. By thus holding back a small 

 portion of blood, the liability of mixing air with the drop 

 is avoided as much as possible. 



E. Lloyd Jones, of Cambridge University, uses a modi- 

 fication of the method of Prof. E,oy. This, which depends 

 upon the same principle as the preceeding, consists in 

 the use of numerous solutions of glycerine and water, 

 the specific gravities of which are known and which are 

 successfully tried until one is obtained corresponding in 

 specific gravity to that of the blood. 



His apparatus consists of twenty to twenty-five one- 

 ounce glass bottles filled with standard solutions of gly- 

 cerine and water, difi"ering one from the other by .001 of 

 specific gravity ; a number of fine glass pipettes drawn 

 out to a point and bent at right angles near the tip ; a 

 cylindrical glass jar of about one dram capacity ; and a 

 number of clean, sharp suture needles. After puncturing 

 the finger on the dorsal aspect near the root of the nail, 

 the blood which exudes of itself or after the finger has 

 been quickly squeezed, is drawn into one of the pipettes. 

 This is introduced into one of the standard solutions and 

 the blood gently blown out. The solution chosen is of 

 high or low specific gravity according to the appearance 

 of the patient. Th^ bent point of the pipette prevents 



