294 MICROSCOPICAL TECHNIQUE. 



the knife at the acute angle they all measured iimm. in breadth, 

 while with the knife at right angle they measured 9^ mm. for the 

 15/i, 9 mm. for the 10^, and 8 mm. for the 5/* sections, thus show- 

 ing a shrinkage of 2, 2^, and 3 mm. respectively. In the case of 

 the thinnest sections, there is a loss in breadth of almost a third 

 of the surface of the block, and such are somewhat incorrectly 

 denominated " sections." They might be called " Quetschen." 



— F. C. Kenyon, in Amer. Naturalist. 



The Recognition of Diabetes by Examination of the Blood. 



—That a swift and certain diagnosis of diabetes may be made by 

 the examination of a single droplet of blood will appear strange 

 to most readers, but Bremer shows, in the Journal der Pharmacie 

 von Elsass-Lothri7igen, how this may be effected by the aid of the 

 microscope, in demonstrating the grape sugar reaction in that 

 vital fluid. He says : — 



"Mix equal volumes of saturated solutions of eosin and 

 methylene-blue, and pour the mixture on a filter as soon as the 

 precipitate ceases to fall. Collect the precipitate, after washing 

 on the filter, dry it carefully, and pulverise it very finely. To this 

 powder add 24 parts of eosin, and 6 parts of methylene-bluc, also 

 in fine powder. This will make a reddish-brown powder. 



The blood to be examined is spread in a very thin layer over 

 a cover-glass, another cover-glass being smeared with a drop from 

 some person known to be healthy, the latter serving for purposes 

 of comparison. 



After drying, put the two cover-glasses simultaneously in a 

 mixture of alcohol and ether in equal parts, put over the water- 

 bath, and let boil for four minutes. Remove and put into a 

 solution made by dissolving from 25 mgm. to 5 cgm. of the mixed 

 powder described above, in 10 gm. of 33 per cent, alcohol 

 (alcohol I part, distilled water 2 parts). This solution, we should 

 remark, should be freshly prepared on each occasion that it is 



required. 



Leave the covers in the stain for about four minutes, remove, 

 rinse with water, and examine under the microscope. If diabetes 

 be present in the person whose blood is under examination, the 

 latter will be coloured a blue black, while normal blood takes on 



