294 TUBERCULOSIS 



local effects without constitutional disturbance, the course of an 

 immunisation may be expected to be rather different from that 

 obtaining in an ordinary acute affection, though the underlying 

 processes may be of the same nature. It is difficult, for instance, 

 on account of the slowness of tubercular processes, to define 

 recovery from an attack of the disease, or to speak of an animal 

 recovering from the effect of an inoculation during an immunisa- 

 tion. It follows that little is known regarding an attenuation of 

 the tubercle bacillus analogous to what is an important feature 

 in immunisations against other organisms. 



Antitubercular Sera. Several attempts have been made to 

 treat tuberculosis with the serum of animals immunised by the 

 tubercle bacillus or its products. The most successful is perhaps 

 that of Maragliano. This author distinguishes between the toxic 

 materials contained in the bodies of the bacilli (which withstand, 

 unchanged, a temperature of 100 C.) and those secreted into 

 the culture fluid (which are destroyed by heat). The substance 

 used by him for immunising his animals consists of three parts 

 of the former and one of the latter. The animals employed are 

 the dog, the ass, the horse. The serum obtained from these is 

 capable of protecting healthy animals against an otherwise fatal 

 dose of tuberculin, but very little importance can be attached to 

 this result. Maragliano does not appear to have studied the 

 effects of this serum on tubercular animals, but it has been tried 

 in a great number of cases of human tuberculosis, 2 c.c. being 

 injected subcutaneously every two days. Improvement is said 

 to have taken place in a certain proportion, especially of mild 

 non-febrile cases. 



An antitubercular serum has also been introduced by Marmorek. 

 This observer considers that the tubercle bacillus cannot produce 

 in ordinary media the toxins which it originates when exposed 

 to the antagonism of the bodily cells. He tries to make good 

 this defect by first growing it in a serum antagonistic to some of 

 the phagocytic cells of the body ; for this a leucotoxic serum is 

 used. When the bacillus has grown in this presumably favour- 

 able soil, it is transferred to a medium containing a substance 

 which may be unfavourable ; and for this there is employed a 

 medium containing liver extract, the liver being an organ in 

 which in man tubercular lesions are comparatively rare. The 

 bacilli being thus accustomed to an unfavourable surrounding 

 are used for immunising animals, the serum of which is now 

 suitable for the treatment of human tuberculosis. There is con- 

 siderable diversity of opinion as to the efficacy of Marmorek's 

 serum as a therapeutic agent. 



