108 SUMMARY OF CURRENT RESEARCHES RELATING TO 



be dry cut. If wet cutting be preferred, the chloroform bath is not 

 used but the blocks are hardened in 80 p.c. alcohol. The author prefers 

 the dry cutting method, and sticks the block on with a thick solution of 

 collodion or with paraffin. As the sections are cut they are placed on 

 strips of specially prepared colour-proof paper, one end of the strip being 

 reserved for notes on identification, &c. When a sufficient number of 

 sections have been placed in position they are flattened down with 

 blotting-paper. The paper strips are then immersed in 80 p.c. alcohol, 

 in which they are freed from the cedar-wood oil. When the sections 

 are to be stained, the strips are placed in a water-bath to extract the 

 alcohol, after which they are treated with hematoxylin, such as 

 hremalum, Grenacher's, Delafield's, in dilute solutions. The strips are 

 placed in tap-water to bring out the colour well and then in 95 p.c. 

 alcohol to which eosin has been added. In this way they are contrast- 

 stained and partially dehydrated. The next step is to treat the sections 

 with carbolxylol (1-3) and then with xylol. What the next procedure 

 is depends on whether it be decided to preserve the strips or examine 

 them in the dry or moist condition. If the latter, the strips are soaked 

 in cedar-wood oil, and then placed on a slide and covered with a strip of 

 glass or mica. 



If they are to be preserved in the dry state, they are coated with 

 elastinlack (Griibler). This varnish dries in from 12 to 24 hours. The 

 strips must be kept in a cool place. 



Staining- the Plague Bacillus.* — E. Horniker obtains excellent polar 

 staining of B. pestis by treating the air-dried and flame-fixed films with 

 saturated alcoholic solutions of methylen-blue and gentian-violet. 

 After allowing the stain to act for l£ to 2 minutes, the preparation is 

 washed with water. 



Staining Malaria Parasites with A-Methylen-Blue-Eosin.f — K. 

 Renter practises the following procedure. The air-dried film is fixed in 

 formol-alcohol (formol 10, absolute alcohol 90), and then carefully dried 

 with blotting-paper. The preparations are then immersed in the stain 

 (aq. destill. 20 c.cm., A-methylen-blue-eosin (Griibler) 30 drops). By 

 tilting the capsule containing the staining solution after the manner of 

 developing a photographic plate the staining process is materially 

 accelerated ; it should be completed in 15-20 minutes. The film is 

 then washed with distilled water, and after having been mopped up and 

 dried in the air, is mounted in balsam. 



Staining the Parasites of Malaria perniciosa.J — G. Maurer re- 

 commends the following procedure for staining the parasites of per- 

 nicious malaria. The chief requisites are a good film, careful drying 

 and hardening, and a very ripe alkaline methylen-blue solution. The 

 slides must be perfectly clean, and the film made after the method of 

 Jancso and Rosenberger. The film is first dried in the air, and then 

 fixed by immersing it for 10 to 15 minutes in alcohol-ether. On re- 

 moval ' it is dried in the air or in the flame. It is then ready for 



* Centralbl. Bakt, l te Abt. Orig., xxxii. (1902) pp. 926-8. 



t Tom. cit., pp. 842-5. J Tom. cit, pp. 695-717 (3 pis.). 



