406 BLOOD AND GLANDS 



dry with blotting paper, dehydrate (about a minute) in a mixture 

 of 2 parts alcohol to 3 of xylol, then one minute in xylol ; then 

 five to ten minutes in alum-anilin (prepared by allowing anilin 

 to stand over a layer of powdered alum a couple of fingers deep) ; 

 xylol, balsam. 



6. As No, 3, supra, after a foregoing stain of two minutes in 

 polychrome methylen blue. 



See also Ehrlich in Virchow's Arch., clxv, 1904, p. 198. 



884. Blood Platelets of Bizzozero. The enumeration of these 

 bodies is of importance to the clinical haematologist. They may 

 be stained in films by any of the Romanowsky stains. According 

 to Pappenheim (Farbchemie, p. 107), wasserblau is almost a 

 specific for them. 



Wright (Journ. Morph., xxi, 1910, p. 274) studied them in 

 tissues, after fixation with formol or sublimate (not Zenker), by 

 staining with a modified Giemsa stain and bringing through 

 acetone and oil of turpentine into turpentine colophonium.* For 

 their enumeration the blood is diluted with some diluting fluid of 

 which there are a great many, the fluid acting as a fixative, anti- 

 coagulant, and usually as a staining solution. A very good fluid 

 is that given by Nicholson {Laboratory Medicine, 1934), consisting 

 of brilliant cresyl blue 0-1 grm. sodium citrate, 0-55 grm. sodium 

 chloride, 0-28 grm. formol, 0-1 c.c, and distilled water 50 c.c. A 

 drop of this is placed on the skin and the needle prick made 

 through the drop. A mixture of blood and the staining solution 

 is collected in a paraffin-lined capsule in the proportion of 1 to 5. 

 Staining occurs almost immediately, and a well mixed drop is 

 placed on a ringed slide, covered with a coverslip, and examined 

 by the oil immersion lens. Platelets may be enumerated by 

 counting the number found in proportion to 1000 red cells. An 

 alternative method is to make a film of the mixture in the ordinary 

 way, stain with any Romanowsky stain and count as before. It is 

 important that the blood be mixed quickly with the diluent so as to 

 prevent the platelets settling. All receptacles and pipettes should 

 be paraflin-lined, since the platelets dissolve on glass surfaces. f 



885. Reticulated Cells or Reticulocytes. In these red blood 

 cells a reticulum or skein-like structure is brought into evidence 

 by a supravital staining with various anilin dyes. Good results 

 are obtained with whole blood as given in the method in § 870. 

 A film is made on a slide with an alcohol solution of cresyl blue 

 (0-3 per cent, is sufficient) and allowed to dry. A drop of fresh 



* Details loc. cit. or Journ. Roy. Mic. Soc, 1910, p. 783. This method 

 demonstrates the megacaryocytes. See also Downey, Folia Haematol., 

 XV, 1913, p. 25, for modifications. 



t See also Deghwitz, Folia Hcematol., xxv, 1920, p. 153 ; Rees and 

 EcKER, J. Am. Med. Assoc., Ixxx, 1923, p. 621 ; and Gradwohl, 

 ibid., cv, 1935, p. 1030. 



