ZOOLOGY AND HOTAX\, MICROSCOPY, ETC. SI 



(4) Staining and Injecting-. 



Method of Staining Parasitic Amoebae.* — The difficulty of satis- 

 factorily staining the amoebae of dysentery and allied forms is in practice 

 considerable, so that any method which can be relied on to give good 

 results is of interest. The following directions are given in a recent 

 communication by Alexander Marshall, of the Wellcome Tropical 

 Research Laboratories at Khartoum. Smears are made from dysenteric 

 stools and transferred rapidly, while still wet, to Schaudinn's fluid. 

 They are then washed in alcohol of different strengths and finally in 

 distilled water, after which they are stained in Delarield's haematoxylin 

 for twenty minutes. They are next washed in tap water and stained 

 with carbol-fuchsin, as for tubercle bacilli ; after which thev are a^ain 

 washed with water and finally differentiated with Sprengel's solution of 

 picric acid, consisting of equal parts of absolute alcohol and of saturated 

 watery solution of the acid. This is applied for three to five minutes, 

 during which time the reagent is changed three or four times. The 

 stained films are then dehydrated in absolute alcohol, cleared in xylol, 

 and mounted in Canada balsam. Thus treated, the nuclei of the 

 parasites are stained a purplish black, while the cytoplasm is a pale 

 translucent yellow colour. Red blood corpuscles are also stained yellow. 

 The method is described as easy, rapid, and certain in its results, and is 

 certainly well worth trial by those called upon to make this investigation. 



Cytology of the Stamens of Smilax herbacea.f — Lilian E. 

 Humphrey carried out an investigation, the primary purpose of which 

 was to observe the reduction division in the microsporocytes of Smilax 

 herbacea. The buds were killed in Schaff ner's weaker chrom-acetic acid and 

 with a trace of osmic acid added, being left in this for twenty-four hours. 

 After being thoroughly washed in water, the material was dehydrated by 

 passing it through the various grades of alcohol to 70 p.c, where it was 

 left for about three months, when it was passed through the higher 

 grades into chloroform, from which it was gradually passed into pure 

 paraffin and embedded. Sections 10> to 13/u thick were cut. 



Several methods of staining were used. The first tried was anilin- 

 safranin, which was a fairly good stain, but it did not make enough 

 differentiation between the chromatin material and the cytoplasm to be 

 easily studied. Next Heidenhain's iron-alum-haematoxylin was used and 

 found to be very good, staining the chromatin material black and the 

 surrounding tissues brownish. In using this stain the slides were passed 

 through turpentine, xylol, the different grades of alcohol to water, then 

 passed through iron-alum, where they were left for two hours ; after 

 being well washed in water, they were left four hours or longer in 



* Lancet (1915) i. p. 145. 



t Ohio Naturalist, xv. (1914) pp. 357-67 (2 pis.). 



Feb. 17 th, 1915 G 



