122 PRACTICAL HISTOLOGY. [ill. 



15. Varieties of Leucocytes in Blood. According to Ehrlich, the following 

 varieties of colourless corpuscles are present in the blood. (Also Lesson 

 XXXVIII.) 



(a.) Small lymphocytes. They are slightly smaller than the red corpuscles, 

 and possess a large spherical readily-stained nucleus, which almost tills the 

 cell, being surrounded only by a small quantity of protoplasm. 



(6.) Large lymphocytes are said to represent an advanced stage of (a). They 

 are twice as large as (a), have a large nucleus surrounded by a well-defined zone 

 of protoplasm, (a) and (&) together make up 25 per cent, of the leucocytes 

 in blood. 



(c.) Mono nuclear elements, or transition forms, are distinguished from the 

 large lymphocytes by their nucleus not being quite spherical, and having a 

 depression in the middle. 



(d.) Poly nuclear leucocytes, which are smaller than (0), but larger than 

 ml blood -corpuscles. They contain a nucleus composed of several lobes, or 

 several nuclei which stain readily and deeply. They represent 70 per cent, of 

 all the leucocytes of the blood, and can migrate from the vessels. 



(e.) Eosinophilous cells. The nucleus stains less deeply than (d). The 

 granules which are present in the protoplasm stain deeply with cosin, i.e., 

 become intensely red. They occur but sparsely in normal blood. 



16. Staining of Leucocytes (Ehrlich). 



(1.) Make a cover-glass preparation of blood and dry it for several hours 



at 120 C. 

 (2.) Stain it for several hours in Ehrlich's aoid-hsematoxylin, eosin 



solution, or in a strong glycerine solution of eosin. 

 (3.) Wash in water, dry and mount in xylol-balsam. 



The nuclei of the white blood-corpuscles, as well as the lymphocytes and 

 polynuclear forms, are deeply coloured ; the nuclei of the mononuclear forms 

 are "bluish-gray, the red corpuscles copper-red, and the eosinophile granules 

 red (Kahlden). 



17. Eosinophilous Cells. If it be desired to stain only these cells, stain a 

 cover-glass preparation with a strong glycerine solution of eosin. The results 

 of Ehrlich and his pupils, will be found in his pamphlet. 1 



18. Action of Hayem's Fluid. This is an extremely useful fluid for pre- 

 serving and fixing the blood-corpuscles, and can be employed both for the 

 blood of animals and of man. It consists of 



Sodic chloride . . . . . i grm. 

 Sodic sulphate .... 5 grins. 



Corrosive sublimate .... 0.5 grm. 

 Distilled water .... 200 cc. 



The blood is run direct from a blood-vessel into this fluid in the proportion 

 of i of blood to 100 of the fluid. It takes several hours to harden and fix (he 

 corpuscles, but twenty-four hours is not too long. By-aml-by the corpuscles 

 subside, and the supernatant fluid can then be decanted, and the deposit cf 

 blood-corpuscles well washed with water to get rid of the salts of the mixture. 

 These corpuscles can then be stained with various reagents, or eosin may be 

 added to the fluid. 



(a.) Make an experiment with frog's blood, and stain the corpuscles fora 

 day or so with borax -carmine and mount the stained corpuscles in glycerine or 

 glycerine-jelly. 



(b.) Stain another specimen with very dilute eosin-hpematoxylin (p. 70). 

 The hremoglobin is stained by the eosin, and the nuclei by the hrematoxylin. 

 It is preserved as (a). Other combinations of dyes will suggest themselves, 

 (c.) Make similar preparations of mammalian blood. 

 1 Farbenanaly. Unters. z. Histologie und Klinik d. B lutes, Berlin, 1891. 



