384 TUBERCULOSIS 



virulent tubercle bacilli by a mechanical process in an agate 

 mortar. The powdered bacilli are suspended in distilled water 

 and centrifugalized. The supernatant fluid has the properties of 

 the old tuberculin, and is called TO (O = obey, = upper). The 

 residue is dried, and again powdered, emulsified, and centri- 

 fugalized, and the bacilli are now found to have been reduced to 

 a uniform mass. This constitutes TR, which thus corresponds 

 somewhat to an endotoxin. It is diluted with 20 per cent, 

 glycerin, and when diluted it is advised that no carbolic acid 

 should be added. There has been a good deal of confusion with 

 regard to the dosage. It arose from the fact that i gramme of the 

 dried tubercle bacilli is used in the preparation of 100 c.c. of the 

 remedy, so that each i c.c. of the latter contains the material 

 derived from 10 milligrammes of bacilli, and is supposed to be 

 equal in immunizing power thereto. But the amount of dry 

 residue which it contains is only one-fifth of this amount, the fluid 

 being standardized before issue, so that i c.c. contains 2 milli- 

 grammes of solid substance. The dosage adopted in this book 

 concerns this dry residue only. 



Tuberculins are also prepared from bovine tubercle (perlsucht) 

 bacilli, and its use mixed with the human form (as recommended 

 by Allen) appears rational and quite worthy of a trial. The 

 majority of cases of human tubercle are due to bacilli of the 

 human type, but at the worst the material derived from the bovine 

 bacilli will be inert and do no harm. 



Another substance used as a vaccine is Koch's Bazillen- 

 emulsion, or Neutuberculin, usually known as BE. It consists 

 of a suspension of dried and ground up bacilli in equal parts of 

 glycerin and water. When used as a vaccine it is diluted with 

 normal saline solution and heated to 60 C. to insure sterility. 

 This may also be done with TR. It contains 5 milligrammes 

 solid substance per c.c. 



As regards the use of these substances : We may recognize 

 two, or perhaps three, methods (i) the intensive ; (2) the opsonic, 

 and (3) the uncontrolled use of small doses. 



i. In the intensive method the idea is to bring about as 

 much immunity as possible as quickly as possible, by the use of 

 rapidly increasing doses, taking care always to avoid a reaction. 

 The commencing dose is very small, about T \j- milligramme 

 ( = TTrijoo c - c -) f ld tuberculin, or T -^^ milligramme (of solid 

 substance) of TR. The dose is repeated two or three times a 



