67G SDMMAUV OF CURRENT RESEARCHES RELATING TO 



TLo time required for staining sections with this nuclear stain is as 

 n rule only a few minutes, but if the material have been hardened in 

 Fleniniiug's mixture 24 hoiirs are necessary. The duration of decoloriz- 

 ing must be judged by the desired eflfect and from the previous staining. 

 The author notes that this black pigment seems to bo very resisting, and 

 tbc prei)arations are very suitable for photograpliic i)urposes. 



The author tlieu proceeds to advocate tbe iise of heat for fixing and 

 preserving material, especially for certain objects such as the ova of 

 Ascaris megaloccphala wbich are impenetrable to the action of ordinary 

 reagents. The thin oviduct of the animal is placed in a test-tube and 

 exposed to the action of water at a temperature which need not exceed 

 50° C, for Max Schulzo has shown that the protoplasm is killed and 

 stiffened at this degree. The test-tube must be continually shaken 

 during the heating. The ova are afterwards hardened in spirit which 

 must be increased in strength. Care must be taken not to overheat the 

 preparation, as their form is thereby much altered. 



By this method certain details in the ova of Ascaris can bo brought 

 out which have hitherto escaped notice. For example, certain elements 

 of the equatorial plate, hitherto described as spherical, now appear as 

 short thick rods which by a distinct fissure may be seen to sei)arate into 

 two dumbbell-shaped daughter elements ; an important point, as it 

 shows agreement with the ordinary type of nuclear fission. 



Baumgarten's Method of Triple-staining.* — Dr. A. Lewin says 

 that excellent results are obtainable by means of Baumgarten's triple- 

 staining method, for which the procedure is as follows : — 



(1) After having washed the sections in absolute alcohol, they arc 

 immersed for five minutes in borax-picrocarmiue ; excess of stain is 

 then removed with filter paper. This picrocarmiuc is prej^ared by 

 adding crystals of powdered picric acid to Grenacher's borax-carmine 

 until the solution assumes a blood-red colour. 



(2) The sections are then passed twice successively into absolute 

 alcohol for two minutes ; to the spirit picric acid is added until the hue 

 resembles that of hock. 



(3) The sections are then soaked in a freshly prepared solution of 

 Ehrlich's gentian- violet (100 parts anilin-oil water and 11 parts alco- 

 holic solution of gentian-violet) for one minute. 



(4) The sections are then immersed in Lugol's iodine solution 

 (iodine 1, iodide of potash 2, water 300) for one minute, after which 

 they are washed in absolute alcohol for thirty seconds. 



(5) Excess of gentian-violet is removed with acidulated spirit (HCl 3, 

 absolute alcohol 97). 



(G) The j)rcparations are then dehydrated in absolute alcohol to 

 which picric acid has been added until the colour is pale yellow (about 

 fi.ve minutes). Afterwards tho sections are cleared uj) in oil of cloves 

 and mounted in xylol balsam. 



Anilin-oil Safranin Solution.! — Dr. V. Babes gives the following 

 moditicution of his anilin-oil safranin, and which he states gives very 

 superior results. It colours sections almost in a moment, is available 

 for all kinds of tissues, and is especially good for showing up mitoses. 

 To 100 parts of water are added 2 parts of aniliu oil and excess of 



* Bull. Roc. Beige de Micr., xiv. (1888) pp. 14G -7. 

 t Ztitbchr. f. Wiss. Mikr., iv. (1887) pp. 470-1. 



