130 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



inserted about three or four finger widths from the aboral end 

 of the larynx into the trachea. See Fig. 3. It is not absolutely 

 necessary that the insertion should be made between two rings 

 because the lancet shaped form of the trocar allows it to pene- 

 trate the rings with ease, even in old animals. See Fig 4. After 

 removal of the stilete, the wire with attached swab is inserted 

 through the trocar into the trachea and its branches, with little or 

 no assistance, to a depth of 1^ meters, then pulled up and down- 

 ward and turned several times and removed. See Fig 5. Tht 

 slime covered swab is placed in a labeled sterilized bottle in which 

 condition it should be taken to the laboratory at the earliest pos- 

 sible moment, for bacteriological examination. Securing lung 

 sputum by the above described method is not met with technical 

 obstacles. The operation when properly performed should be 

 bloodless and is not accompanied by any bad results, which we 

 have demonstrated by many observations and experiments. Com- 

 plications resulting from this operation are hardly possible, 

 owing to the fact that the trocar's sharp cutting surface makes 

 only a small wound which readily heals in a few days. This 

 has been proven by postmortem on animals which had been oper- 

 ated a few days previous. To form an accurate opinion of the 

 value of this method of determining open tuberculosis in a liv- 

 ing animal, we conducted numerous experiments on cattle at the 

 slaughterhouse, the results of which will be given in detail. 

 Thanks are due to Dr. Henschel, Chief Veterinarian of the Abat- 

 toir, who made it possible for us to conduct these experiments. 



Method of Experiments. 



1. Physical examination of cattle. 



2. Securing lung sputum. 



3. Post mortem examination immediately after slaughter. 



4. Microscopical examination of a smear preparation from 

 the swab. 



5. Animal inoculation with material in at least two Guinea 

 Pigs. 



6. Post Mortem examination of inoculated animals six 

 weeks later. 



