DIRECTIONS FOE LABORATORY WORK 789 



(D) HEMOGLOBIN CRYSTALS. 



Place large drop of blood on slide in a small drop of distilled water. 

 Allow to dry slowly. Mount when dry in balsam under cover-glass. Ex- 

 amine h.p. for crystals. Note shape, size and color. Sketch (177). 



(E) HEM IN CRYSTALS. 



Place a drop of blood on slide. Add 2 or 3 grains of sodium chloride 

 and a drop of glacial acetic acid. Heat slowly over flame of a Bunsen 

 burner until bubbles begin to appear. Mount in balsam. Examine h.p. 

 for crystals. Note shape, size and color. Sketch (178) several isolated 

 crystals and several groups. 



(F) BLOOD DEVELOPMENT (Hemopoiesis). 



(1) IN EMBRYO. Sketch (179) a few blood cells from a young 

 mammalian embryo, noting the several types of embryonic erythrocytes : 

 (a) hemoblasts, (b) erythroblasts, (e) normoblasts. 



(2) IN ADULT BONE MARROW. Study with oil immersion lens smear 

 preparation or a section of red bone marrow (e.g., of femur of rabbit or 

 guinea pig), stained in Wright's solution. Identify and sketch (180) 

 the several types of myelocytes: (a) myeloblast, (b) leucoblast, (c) 

 erythroblast ; also (d) myeloplaxes (giant cells), (e) erythrocytes, (f) 

 the several types of granular myelocytes: eosinophil, basophil and 'spe- 

 cial' (neutrophil of higher mammals), and (g) origin of platelets from 

 pseudopods of megakaryocytes. Note cells in process of division, both 

 mitotic and amitotic. Note also the framework of reticular connective 

 tissue (reticulum) ; and the process of extrusion of the nucleus of a 

 normoblast in the formation of an erythroplastid. Compare with sec- 

 tion of red marrow of femur of frog. Differences ? Make similar study 

 of fragment of marrow of femur of rabbit or guinea pig, preserved in 

 aceto-carmin, and teased in glycerin. 



XI. THE LYMPHATIC SYSTEM 



(A) LYMPH. 



Study a smear preparation of lymph stained with Wright's stain 

 from the thoracic duct of a dog. Sketch (181) the several types of 

 leucocytes. Which type predominates? Do blood platelets occur in 

 lymph ? Bed blood corpuscles ? Origin of lymph ? Consider the coagu- 

 lation of lymph. 



