METHODS OF EXAMINATION 265 



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. Improve- 

 ment is said to have taken place in a certain proportion, especi- 

 ally 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 antago- 

 nistic to some of the phagocytic cells of the body ; for this a 

 leucotoxic serum is used. When the bacillus has grown in this 

 presumably favourable soil it is transferred to a medium con- 

 taining 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 tuber- 

 culosis. It is too soon to speak of th effects of this line of 

 treatment. 



Methods of Examination. (1) Microscopic Examination. 

 Tuberculosis is one of the comparatively few diseases in which a 

 diagnosis can usually be definitely made by microscopic examina- 

 tion alone. In the case of sputum, one of the yellowish 

 fragments which are often present ought to be selected ; dried 

 films are then prepared in the usual way and stained by the 

 Ziehl-Neelsen method (p. 101). In the case of urine or other 

 fluids a deposit should first be obtained by centrifugalising a 

 quantity in a test-tube, or by allowing the fluids to stand in a 

 tall glass vessel (an ordinary burette is very convenient). Film 

 preparations are then made with the deposit and treated as 

 before. If a negative result is obtained in a suspected case, 

 repeated examination should be undertaken. To avoid risk of 

 contamination with the smegma bacillus the meatus of the 

 urethra should be cleansed and the urine first passed should be 

 rejected, or the urine may be drawn off with a sterile catheter. 

 As stated above it is only exceptionally that difficulty will arise 



