CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 161 



become coufluent and cause deep and extensive sores invading tlie sub- 

 jacent cartilage and other tissues. 



Sometimes the brain and s])inal cord are invaded, but especially the 

 pia mater and arachnoid, giving rise to the most varied nervous symp- 

 toms, and passing through the same changes with an especial tendency 

 to puriform softening when in the brain substance. 



Tubercular deT)osits in the coats of the bowels are found in cattle in 

 tlie form of nodules varying in size from a pin's head to a hempseed on 

 the inner surface of the peritoneum (Niklas), and in pigs in the forms 

 forms known as scrofula or caseous enterites. 



The miliary nodules and aggregations of them are also found in the 

 ]i\er and spleen, less frequently in kidneys and bladder, and in the iren- 

 erative organs (tunica vaginalis, cord, testicle, uterus, ovaries, Fallo- 

 pian tubes, vagina), and in the mummary glands. The mus(;les are 

 occasionally the seat of tubercle, and the bones rather frequently so. 

 The neoplasm takes place by preference in the cancellated tissue of the 

 extiemities of long bones, and in that of the bones of the cranium, and 

 the spines of the dorsal vertebra^. 



T\ni relative frequev.cy of the more common seats may be deduced 

 from the followiug table of 1,590 cases observed in Baden : 



Per conf. 



Lesions of the lunjis only •>! 



Lesions of pcritouenm ami pleura only 28 



Lesions imlnionary anil pleural :i<» 



Lesions of generalized tuberculosis <) 



Lesions of {^enerati ve orgaus only ;{ 



Microscopically the tubercular products are composed of — 



{a.) Excessive growth of new connective lis ue which, in the lungs, 

 may amount to ~)~) to 100 pounds. 



(6.) Connective tissue growths interspersed with centers of degenera- 

 tion : ./fr,s7, hemorrhagic points; second, small \itreous looking masses, 

 and, third, soft caseous collections. Both these forms show a stnmg- 

 propensity to calcification, and in bones to genuine ossification. 



(6'.) Sarcomatous neoplasms or tubercular nodosities. These have a 

 Aiiscular stro?na of connective tissue inclosing masses of round lym- 

 ]»hoid and fusiform cells. The peripheral cells have a clear outliue, 

 and there are few free nuclei, while in the center the cells become opacpie 

 and indistinct with little protoplasm and shriveled nuclei and free 

 luiclei and grannies abound. These also are often calcareous. 



(d.) Tubercles varying in size from a millet seed to a hen's e^ig. These 

 ai)pear in the paren(;hymatous tissue of the lung-, &c., while those for- 

 merly described attect ra\her the surface and the serous membranes. 

 These are at first sniall and translucent, but increase by juxtaposition 

 and confluence, and being exclusively cellular become early (calcified, 

 or more frequently caseated. These are much more numerous in an in- 

 fected tissue than any product likely to be mistaken for them. 



{e.) Ulcers of various forms and dimensions. In all these lesions 

 5751 T) A 1 1 



