TREPONEMA PALLIDUM 147 



the last forms being called vaccines also. We inject 

 them under the skin of tuberculous patients, beginning 

 with extremely minute doses, too small to produce 

 the tuberculin reaction described above. We increase 

 the quantity gradually until the patient can endure 

 large amounts. It is maintained that this treatment 

 is very beneficial and that a slight immunity is achieved. 

 Opinions vary as to its value, but those who have had 

 longest experience usually testify to its efficacy. This 

 is in reality an active immunization during the course 

 of the disease, but it has not been found possible to 

 inject a healthy person in the same manner and 

 thereby increase his resistance to tuberculosis. 



TREPONEMA PALLIDUM 



Syphilis is one of the venereal diseases. It is chiefly 

 acquired by cohabitation, but may also be contracted 

 by nurses and physicians in their professional relations 

 with patients. It is a chronic infectious disease 

 characterized by three stages, the first a primary, 

 acute, active self-limited ulceration, with some regional 

 lymph gland swellings; second, a period in which 

 various eruptions appear on the skin and mucous 

 membranes, with slowly progressive changes in some 

 of the internal organs, and third, a last stage of soft 

 tumor formation (gumma), with fibrous affections of 

 the organs and degenerations of the nervous system. 



It is caused by a spiral organism called the Spiro- 

 chceta pallida or Treponema pallidum This bac- 

 terium enters small cracks or wounds, penetrates to 

 the deeper layers, invades the lymph channels, and 



