440 INFECTIVE DISEASES. 



are placed for an hour in Wedl's solution of orseille, which is prepared 

 as follows : Add liquid extract of orseille to a mixture of absolute 

 alcohol 20 parts, strong acetic acid 5 parts, distilled water 40 parts, 

 until a dark-red liquid results. This must be filtered before use. The 

 sections are left in this solution for an hour, then just rinsed in alcohol, 

 and transferred to a solution of gentian-violet. Such sections show the 

 nuclei of a violet-blue colour, and the peripheral part of the central core 

 in the larger masses of the fungus also takes a blue colour, while the 

 club-shaped structures are stained a striking wine-red colour. 



Plant's Method and Modifications. This is one of the most valuable 

 methods for staining the clubs. The original method was to float sections 

 for ten minutes in magenta solution warmed to 45 C. This solution 

 consisted of magenta two parts, aniline-oil 3 parts, alcohol of specific 

 gravity 0'830, 20 parts, distilled water 20 parts (Gibbes). The sections 

 were then rinsed in water, stained in concentrated alcoholic solution of 

 picric acid for from five to ten minutes, immersed in water five minutes, 

 50 per cent, alcohol fifteen minutes, passed through absolute alcohol and 

 clove-oil, and preserved in Canada balsam. The clubs are stained a 

 brilliant red and the tissue yellow. Instead of employing the magenta 

 solution, we now use Ziehl-Neelsen's solution. 



By removing the picric acid in Plant's method by prolonged immersion 

 in alcohol, and then staining with gentian-violet or methylene-blue, a 

 very successful contrast can be obtained. The most instructive histo- 

 logical picture can be obtained by first staining with Neelsen's solution, 

 removing the stain from the tissue in the way that has been already 

 described, and then transferring the sections to distilled water, and 

 subsequently staining with Ehrlich's histological stain. 



Ehrlictis New Histological Stain. This is a combination of Ehrlich's 

 logwood with orange-rubin. It is of especial value for sections of 

 actinomycosis, and particularly in combination with carbolised fuchsine. 

 It is employed in the following way : The sections must be placed in 

 alcohol or distilled water, and then in Ehrlich's logwood for about half 

 a minute. From this solution they are transferred to distilled water, 

 washed to remove the excess of stain, and then placed in a large dish of 

 tap-water, where they are left for half an hour or more, until the 

 sections turn blue ; if preferred, they may be left overnight. They are 

 then stained for one or two minutes in a solution of rubin, S, and 

 orange, and washed again in distilled water to remove the excess. They 

 must then be dehydrated in alcohol, cleared in clove-oil, and mounted in 

 balsam. 



Preparation of Large Sections. 



The method of cutting large sections of organs may be employed 

 in studying actinomycosis. The value of these sections depends not 

 only upon their affording an instructive picture of the naked-eye 

 appearances, but they can also be studied with a pocket lens, or under 

 the microscope with a | or -in. objective. By staining the sections, the 

 relation of the morbid to the healthy structures is brought out in greater 

 contrast, and thus the topography of the disease can be studied more 



