286 THE INFECTIOUS DISEASES. 



in the__marrow. Crescentic organisms may be present in the marrow 

 even if these have not beerrpresent in the blood during life. 



The spleen is increased in size, the pulp is softened and very dark, 

 the Malpighian bodies are not well marked. Microscopically, the organ 

 is greatly congested ; many of the red cells^are invaded by the plasmodia 

 which are often in the segmenting stage. There is a very activejjhago- 

 cytosisjjy the macrophages present, often so extensive as to includetne" 

 reef cells with tBerFconfained parasites. 



In the chronic cases, the patient may become extremely anaemic with 

 nucleated red rails in the blood and a great reduction in the number of 

 ^rythroblatg. The spleen~Is greatly enlarged, the capsule thickened and 

 adherent to the surrounding tissues. The cut section of the organ_is^of 

 a dark brown or slaty black from the deposit of pigment. The Mal- 

 pighian bodies arc well marked. The fibrous-tissue trabeculae are 

 as is the reticulum of the pulp ; the pulp cells are pigmented. 

 shows a marked pigmentation, especially in the eudothelium 

 of the capillaries and in the so-called perivascular cells described by 

 Kupffer, while occasionally there is a moderate amount of new connec- 

 Jiye tissue, which, however, does not follow, as a rule, the anatomical^ 

 distribution of the connective tissue in the usual atrophic cirrhosis. In 

 chronic poisoning the kidneys may show a chronic diffuse nephritis. The 

 Qjone marrowfrnay remain fairly normal except for the deposition of pig- 

 ment, or there may be seen ajqarked hyperplasia with replacement~Vf 

 the^normal fatty marrow of the shafts of the long bones with red marrow 

 containing normoblasts or even megaloblasts, if the disease has been long- 

 continued and severe. ' 



Methods of Examination of the Blood in Malaria. 



There are two methods of examining the blood for plasmodia, in fresh preparations 

 and in stained smears. Both require considerable training, as the artefacts produced by 

 imperfect technique have often been mistaken for organisms. 



THE EXAMINATION OF FRESH BLOOD. To examine the fresh blood, a puncture is 

 made in the pulp of the finger and a perfectly clean cover-glass just touched to the top 

 of the drop of blood which exudes from the puncture. The cover is then dropped 

 without pressure on a clean slide. The diameter of the drop on the cover-glass should 

 never exceed 2 mm., because if more be taken the corpuscles cannot spread out in a per- 

 fectly thin layer, but will overlap each other and the preparation will be useless. The 

 search for the organism should be made with a one-twelfth oil-immersion lens and a 

 moderate illumination. The organisms are best recognized by the actively motile pig- 

 ment in the clear, highly refractile cell body. 



THE EXAMINATION OF BLOOD AFTER FIXATION. If the examination cannot be 

 made at once, stained preparations may be made. The smear should be made on a slide 

 or large cover-glass. It is best fixed in a mixture of formalin and strong alcohol for 



1 A general bibliography of malaria to 1895 is contained in the excellent monograph 

 of TJiayer and Hewetson, "The Malarial Fevers of Baltimore," Johns Hopkins Hospital 

 Reports, vol. v., 1895. The more recent literature, especially that relating to the de- 

 velopment of the organisms in the mosquito, is in Marchiafata and Bignami, article 

 "Malaria" in "Twentieth Century Practice," New York, 1900, and also LilJie, "Neuere 

 Sporozoenforschung," Centralbl. f. Bakt., Bd. xxvii, and xxviii., 1900. For a study of 

 structure and biology of Anopheles, see Nuttall and Shipley, Jour, of Hygiene, vol. i., 

 1902. For practical directions for the study of mosquitoes, see Berkeley, " Laboratory 

 Work with Mosquitos," 1902. 



