380 THE BLOOD AND THE BLOOD-FORMIXGr ORGANS. 



most infectious diseases. In the first weeks of the disease there is usu- 

 ally a reduction in the number of leucocytes, especially of the poly nuclear 

 forms. In the later weeks the lymphocytes may form eighty per cent 

 of the leucocytes present in the blood. Each relapse is attended with an 

 increase of the lymphocytosis, while an increase of polyuuclear leucocytes 

 usually occurs with complications only. 



In the various forms of tuberculosis there is no leucoeytosis unless 

 the lesion is markedly exudative in character, as in tuberculous menin- 

 gitis, or is complicated by suppuration or chronic anaemia. In pulmo- 

 nary tuberculosis with secondary infection by pyogeuic cocci leucocytosis 

 is apt to develop. 



Cachectic Leucocytosis is a feature of altered conditions of the blood, 

 such as are ajssociated^with the growth of_^alignant^ tumors, and with 

 many diseases_producing secondary anaemia. This increase of poly- 

 ^itrctearTeucocytes ni^^erve~to"dTstiuguisE many forms of secondary 

 from primary anaemia. The inflammation and toxaemia accompanying 

 many new growths afford a sufficient reason for the appearance of ca- 

 chectic leucocytosis, but under many other circumstances its direct cause 

 is less apparent. ' 



Hypoleucocytosis occurs not only in infectious diseases, when the poly- 

 nuclear cells alone are reduced in numbers, but also from shock, reduc- 

 tion of body temperature, and exhaustion, when all forms of leucocytes 

 may be diminished. It is a fairly constant feature of primary pernicious 

 anaemia. 2 



Polynuclear Eosinophile Leucocytosis is found in a number of unrelated 

 conditions. In brondhiai asthma the eoamofihile cells are considerably 

 Jyp.frftaflp.dj often forrning^ten^ to twenty per pent of the total white cells. 

 Iji_acute_and chronic diseases of gie skmTsuch as pemphigus, prurigo r 

 and psoriasis, the eosinophiles are often increased to a marked degree, 

 but the condition is not constant. j[n trichinosis and helminthiasis the 

 increase is so constant that it becomes of diagnostic value in these con- 

 ditions. A post-febrile eosinophilia is frequently observed. 



Lymphocytosis, frequently seen in the anaemias, in pertugsjs. and the 

 acute intestinal disorders of childhood, has also been noted in some 

 forms of secondary amernia (syphilis), and in an extreme degree as the 

 chief characteristic of the blood of lymphatic leukaemia. 



In joixed leucocytoses a number of types of cells appear which are de.- 

 rived from thTTjoue_ marrow and differ greatly from the forms already 

 described. Of these the most importaut~are the myelocytes (Plate II., 

 Fig. 6). These are mononuclear cells with an oval, faintly staining 

 nucleus, and a cell body containing a greater or less number of neutro- 

 phile granulations. They are usually about twice as large as the red 



'For further data concerning Leucocytosis, consult Rieder, "Beitrage zur Kennt- 

 niss d. Leukocytose," Leipsic, 1892. Turk, "Klin. Untersuchungen u. d. Verlialten d. 

 Blutes," etc., Wien, 1898. 



2 For Hypoleucocytosis, consult Lmcit, "Studien liber Physiol. und Pathol. d. 

 Blutes u. d. Lymphe," Jena, 1892. Ewing, "Toxic Hypoleucocytosis," New York 

 Medicnl Journal, March, 1895. 



