570 Tuberculosis. 



not be looked upon as conclusive evidence. Strictly speaking, this is 

 also true in the examination of milk because paratubercle bacilli may 

 gain entrance into the lactiferous ducts through the excretory canals 

 (De Jong). Nevertheless this is only of rare occurrence. (Ostertag, 

 in his extensive investigations along these lines never found acid-fast 

 bacilli in freshly drawn milk, while Bang failed only 26 times in 2,174 

 eases in which tuberculosis was diagnosed on the basis of an examination 

 of the milk.) Accordingly, the demonstration . of acid-fast bacilli in 

 milk drawn after the first few streams from the udder have been dis- 

 carded may, though not with absolute certainty, be looked upon as 

 in all probability indicating the presence of tuberculosis. In regard 

 to other secretions, especially those of the bronchial tubes, the possi- 

 bilities of contamination are much greater and consequently greater 

 caution must be exercised in making a diagnosis on the strength of a 

 bacteriological examination. But even in these cases the demonstration 

 of acid-fast bacilli, slender in form and irregularly stained, point with 

 great probability to the presence of tuberculosis while, on the other 

 hand, the occurrence of these forms in the vaginal secretions is of less 

 definite value and their occurrence in the feces has slight significance 

 only. 



In the living animal a resected subcutaneous lymph gland or other nodule, 

 the purposely removed contents of an abscess, aspirated exudate from' the thoracic 

 cavity or from the joints, suspected tissue from the udder removed with a harpoon 

 or milk drawn under aseptic precautions are materials best suited for examination. 

 Ejecta from the lungs, nasal discharge, pus from, an already open abscess 

 or joint, secretions from ulcers, urine, spermatic fluid and vaginal secretions may 

 also be examined. Since animals seldom discharge bronchial secretions directly into 

 the outer world (although expelled particles are now and then to be found adhering 

 to the wall immediately in front of the animal's head, in the stall) these must 

 be obtained by specially devised artificial methods. Holding a cloth over the 

 mouth and nose and then forcing a cough impulse by compression of the nostrils 

 will enable one to obtain particles of mucus which lodge on the cloth (Leeuwen). 

 The same results may be obtained by forcing the animal to cough against a board 

 wall or a linen cloth held immediately in front of it. After the animal is through 

 coughing, masses of mucus are usually lodged between the tongue and molar teeth 

 where they can be removed by hand. The mucus which remains lodged on the 

 pharyngeal membrane may be removed by means of a small wad of cotton or 

 a sponge attached to the end of a flexible rod (Noeard, GrefSer, MacFadyean). 

 According to Ostertag the use of a small spoon with handle about 45 cm. long is 

 more practical. Previous injections of pilocarpine have no value, because they 

 simply increase the quantity of secretions, the purulent admixture containing 

 relatively fewer tubercle bacilli. Hasenkamp constructed a special instrument for 

 this purpose (" Lungenschleimfaenger" pulmonary mucus collector) consisting of 

 an elastic rod with a pear-shaped cup attached to one end. The cup end is 

 inserted into the esophagus, the animal forced to cough and, after swallowing, 

 the "mucus collector" is withdrawn, filled with mucus! Poels recommends trache- 

 otomy at the lower end of the trachea and the removal of secretion from the 

 posterior tracheal wall with a cotton swab. Neuhaus uses Dieckerhoff's venous 

 trocar, inserting the same into the trachea and then, by means of small chicken 

 feathers passed through the canula, causes the animal to cough, whereupon the 

 expelled mucus is caught up by the feathers. 



Forcing a cough impulse while the tongue is mechanically pulled part way 

 out of the mouth prevents the animal from swallowing and thus permits the 

 collection of expelled masses of mucus; bending the head forward and downward 

 while the animal is coughing may enable one to collect the discharged saliva on 

 a plate and then examine the particles of mucus which it may contain (Klauwers). 



Microscopic examination of discharges from the lungs does not always give 

 positive results even in open pulmonary tuberculosis Negative findings, therefore, 

 do not necessarily exclude the presence of tuberculosis. Among 77 cases attended 

 with bronchial rales, Ostertag found tubercle bacilli in only 27. In 11 cases 

 he found bacteria resembling tubercle bacilli in appearance and in 11 other cases 

 short thick acid-fast rods were present while the examination gave negative results 

 in 29 instances. He succeeded only once in demonstrating tubercle bacilli in open 

 tuberculosis without rales. 



