. The elements of pathological histology with special reference to practical methods . ales and fragments,which only at times unite into larger conglomerations. The tubercle bacilli are the exciting cause of tuberculosis, in-cluding under this term, however, the caseating inflammations,scrofula, lupus, and tubercular disease of the serous membranes{Perlsucht). BACILLUS TUBERCULOSIS 131 In man, infection takes place most frequently by the inhalation oftubercular sputum which has become dried and reduced to dust; andnext by the introduction of tubercle bacilli with the food (oftenest inthe unboi
. The elements of pathological histology with special reference to practical methods . ales and fragments,which only at times unite into larger conglomerations. The tubercle bacilli are the exciting cause of tuberculosis, in-cluding under this term, however, the caseating inflammations,scrofula, lupus, and tubercular disease of the serous membranes{Perlsucht). BACILLUS TUBERCULOSIS 131 In man, infection takes place most frequently by the inhalation oftubercular sputum which has become dried and reduced to dust; andnext by the introduction of tubercle bacilli with the food (oftenest inthe unboiled milk of tubercular cows); by penetration of the bacilliinto wounds of the skin and mucous membranes ; and perhaps also bytransmission of tubercle bacilli to the ovum with the semen, or tothe foetus through the placenta. The entrance of tubercle bacilli into the tissues is followed bya growth of the fixed cells of the latter, from which there areformed cells of larger size and usually containing oval vesicularnuclei which do not stain very deeply, epithelioid cells (Fig. 60, a).. Fio. 00.—Two Tubercles in a Lymphatic Gland, x 240. (Alumcochineal.) a, Epithelioid cells ; b, Round cells of gland ; c, Reticulum. These then by their accumulation form rounded tolerably sharply-defined nodules containing no blood-vessels {epithelioid-celled tuhercles).The stroma of the parent tissue, being forced apart by the epithe-lioid cells, assumes a more or less distinctly reticular structure as faras the tubercle extends (reticulated ticberclc ; Fig. 61, d). A furtherresult is usually the emigration from the neighbouring blood-vesselsof leucocytes, mostly of the mononuclear variety, w^hich collect asa rule at the periphery of the nodule (Fig. 61, a), but may alsopenetrate into its interior; and when the emigration takes placevery early, or at all events to an excessive degree, nodules occurwhich are composed exclusively of lymphoid cells {lymphoid tubercles).In the ce
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpatholo, bookyear1895
