256 



THE IN FACTIOUS DISEASES. 



Various reports of success in the artificial cultivation of the lepra bacillus have not 

 yet received the seal of experimental confirmation. 



The lepra bacillus may be conveyed from man to man by direct inoculation ; but 

 under proper sanitary conditions the disease is rarely initiated in this way. In a few 

 cases animal inoculations have been made with what appear to be positive results. 1 



The structure of the new tissue growth, the absence of coagulation 

 necrosis, and the peculiar grouping of the bacilli in the large transparent 

 cells are characters which usually clearly distinguish the lesions caused 

 by the leprosy bacillus from those of tuberculosis. 



Leprosy is common in India and in other hot countries. It is infre- 

 quent in America, but in the Gulf States, in Mexico, among the Norwe- 

 gians in the Northwest, and in the eastern British provinces a considerable 

 number of cases are grouped. Isolated cases are, however, encountered 

 now and then in various parts of the United States. 



SYPHILIS. 



The characteristic lesions of syphilis consist in a more or less circum- 

 scribed formation of new tissue. This may be made up largely of small 

 spheroidal cells or of these with polyhedral cells (Fig. 127), and of occa- 

 sional giant cells. The new tissue, which may be diffuse or in more or 

 less clearly circumscribed masses, contains, as a rule, few blood-vessels, 



and is prone to undergo coagu- 

 lation necrosis. This tendency 

 is most pronounced in the cir 

 cumscribed masses. 



The endothelial cells of the 

 blood-vessels in and near the 



illflammat . r y foci in this form 



of inflammation are not infre- 

 quently swollen and may pro- 

 liferate (Figs. 127 and 128, B\ 

 The vessels may otherwise un- 

 dergo extensive changes. 



In the primary lesion, which 

 is called chancre, there may be 

 obliterating endarteritis, a 

 small spheroidal -cell infiltra- 

 tion of the connective tissue, 



proliferation of connective -tissue cells, especially near the blood-vessels 

 (Fig. 129), swelling of the vascular endothelium, and an occasional de- 

 velopment of giant cells. This new tissue may become fibrous or ne- 

 crotic and may ulcerate. 



Following the primary lesion there may be inflammation of the lymph 

 nodes, of the skin and mucous membranes, of the bones and viscera. 



1 For bibliography of leprosy consult Morrow, "Twentieth Century Practice," vol. 

 xviii. 



FIG. 127. NEW-FORMED TISSUE IN SYPHILITIC INFLAM- 

 MATION. 



Fi-om a "hard chancre," showing swollen endothelium in 

 a small blood-vessel. 



