TUBERCULOSIS. 341 



8. In certain tuberculoas animals, not feveied, the reaction 

 consecutive to the injection of tuberculin does not reach 

 more than 1"4° ; still, as experience shows that in per- 

 fectly healthy animals the temperature may undergo 

 variations of 1-4° or more, only reactions above 2*4° 

 should be allowed to have any real diagnostic value. All 

 animals in which the injection is followed by a rise of 

 1|° to 2^° should be considered as suspect, and ought 

 to undergo a new injection after the lapse of about a 

 month. 



Crookshanks and Herroun have separated a ptomaine and an 

 albumose from the crude glycerine extract of cultures, which, 

 when ejected hypodermically into tubercular guinea-pigs, 

 induces a rise of temperature, and its effect on tubercular 

 glands in the cases associated with rise of temperature was to 

 render them well defined, indurated, and painful. Other ex- 

 periments have been made to determine the action of the 

 amide group of organic substances upon the economy in health 

 and in tuberculosis. In a report by Professor Samuel G. Dixon, 

 M.D., and W. L. Zuill, M.D.D.V.S., Academy of Natural Science, 

 Philadelphia, it is stated that, in endeavouring to discover the 

 true nature of the active principle of tuberculin, a crystalline 

 substance was produced that at once suggested the amide 

 group, — allantoin, glycocin, tyrosin, kreatin and kreatinin, 

 taurin, cystin, &c. They determined to make use of kreatin, 

 which was at hand, and injected a small quantity into tuber- 

 culous and healthy small animals, and afterwards by Zuill 

 into cattle, with results resembling those obtained by tuber- 

 culin. Zuill states that the action of kreatin upon tuber- 

 cular tissue is intensely energetic, causing its rapid necrosis, 

 giving it the appearance of having undergone a cystic de- 

 generation. Experiments with taurin also caused elevation of 

 temperature. 



Mr. George N. Kinnell, M.RC.V.S., Pittsfield, Mass., re- 

 ports, 1895, that more definite results are obtained by using 

 smaller doses of tuberculin. He says : " By a smaller dose 1 

 mean two-thirds of a minim ; a large dose, the ordinary one 

 from three to five minims — of Libbertz's Tuberculinum Kochii. 

 The small doses will not cause reaction in the earlier stages, 

 or where the disease is but slightly advanced, but will do so in 



