INOCULATION EXPEKIMENTS. 161 



duced forty-three pure cultures, some of which he continued through 

 over thirty generations, occupying a period of two years. We shall 

 see that inoculations with material from so-called scrofulous glands 

 produce the same effect as when lupus tissue is used, and must, 

 therefore, attribute their existence to the same cause. 



Arloing (Comptes rendus, t. xcix. p. 661) prepared an emulsion 

 from a simple scrofulous gland, caseous in the centre, which was 

 taken from a boy aged fourteen. This was injected beneath the 

 skin of ten rabbits and the same number of guinea-pigs. Visceral 

 tuberculosis developed in all guinea-pigs, but the rabbits remained 

 healthy, except that two showed yellow caseous granulations at the 

 seat of inoculation. From a gland removed later, from the same 

 boy, a similar emulsion was made and injected into the peritoneal 

 cavity of six rabbits and six guinea-pigs. As before, the guinea- 

 pigs all presented tubercular lesions ; the rabbits, on being killed, 

 were found to be perfectly healthy. In two instances, pus from 

 strumous abscesses gave similar results. Some glands excised from 

 the neck of a young woman produced tuberculosis both in rabbits 

 and in guinea-pigs, but the patient died three weeks after the opera- 

 tion from miliary tuberculosis. Arloing appears to consider this 

 case as outside the general category of strumous glands. From 

 these experiments he inferred that either scrofula and tuberculosis 

 were nearly allied affections, but caused by different agents, or they 

 were derived from a single virus, of which the activity was modified 

 in the scrofulous form. 



Bollinger ( u Ueber den Einflus der Verdiinnung auf die Wirk- 

 samkeit des tuberculosen Giftes," Munch, med. Wochenschrift, No. 

 43, 1889) has studied experimentally the effect of dilutions of 

 tuberculosis material. He found that infectious milk from a tuber- 

 culous cow which produced typical local tuberculosis by iutra- 

 peritoneal injections, if diluted from 1 : 40 to 1 : 100 has lost its 

 virulence. The sputum of phthisical patients was found much 

 more virulent and had not lost its power to produce tuberculosis on 

 being diluted 1 : 100,000, on being injected into the abdominal 

 cavity or the subcutaneous connective-tissue. Feeding experiments 

 with sputum diluted 1 : 8 yielded negative results. Pure cultures 

 remained virulent when diluted 1 : 400,000. All the experiments 

 proved that the more concentrated the material and the greater the 

 number of bacilli the more rapid and intense was the development 

 of the lesion caused by the injection. In guinea-pigs it was esti- 

 mated that about 820 bacilli were necessary to produce fatal tuber- 

 culosis. Intra-peritoneal injections did not always produce peri- 

 toneal tuberculosis, and when this was absent the organs affected 

 were the lymphatic glands, spleen, lungs, liver, kidneys, and 

 genital organs in the order of frequency named, showing that 



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