296 ANNUAL REPORT OP THE Off. Doc, 



your stable are plenty of inlets and outlets and still they may not 

 be arranged so as to create a current of air. You may have your 

 air stagnant; but you raise your outlet 15 or 20 feet and it will 

 take your hat up, there Avill be a great circulation of air; there is 

 where the mistake is made. 



Never be satisfied from a theoretical plan. I have seen theoretical 

 plans followed absolutely and still you got no current of air or if 

 there was any current it was in the opposite way to that from 

 which we are expected to go. Apply your own good common sense, 

 put another piece of stove pipe on your outlet, a piece 6 or 7 feet 

 long, and you will be surprised to see the result, it changes the 

 whole situation, creates a current, and that is what you want in a 

 cow stable. You don't want to have your cows closely confined in an 

 excellent stable; you may build the finest cement barn with good 

 tight windows and a cold winter's night you come in there and the 

 cows are nice and warm, but there around the windows and on the 

 wall is a condensation of moisture which is an indication that that 

 stable is very, very badly ventilated, and that is one of the causes, 

 in my mind, one of the most potent factors in the contributory 

 causes to the spread of tuberculosis, the confinement of the air in 

 a barn. 



Now that gets us back to the tuberculin test ; that seems to be the 

 bone of contention; it may be because it is more or less compli- 

 cated. It may be because it required application, very close ap- 

 plication of the operator, of the tester. It requires the cleanest sort 

 of observation, so as to be able to determine just what caused a 

 sudden elevation and dropping of the temperature during the pro- 

 cess of testing. There is a cause for all those things. It may not be 

 due to tuberculosis, but there is a cause for these irregular tempera- 

 tures. 



Now then, in the first place, we have got to get our tuberculin... 

 as I spoke of, we have got to get good tuberculin and we have got 

 to have fresh tuberculin. Mistakes have been made by using tuber- 

 culin that had deteriorated, that had been in a warm closet or a 

 desk drawer or on the mantlepiece or in the barn for an indefinite 

 period of time. Don't take any chances like that, because you can- 

 not expect to get any results. Do not use any of your left-over 

 tuberculin, get the fresh stuff. Upon the quality of that tuberculin 

 depends an accurate result, and it means money to you if a mis- 

 take is made. 



The next step is to see that the cow receives the dose intended. If 

 you want to give a certain amount of tuberculin, you want to be 

 sure the cow gets it. If you give just two-fifths of a cubic centi- 

 meter, which is a very small amount of tuberculin, it is almost an 

 impossibility to get it all out of your needle, to get it all into the 

 cow. Therefore it is well to dilute your crude tuberculin, to take 

 two-fifths of a cubic centimeter of tuberculin and add enough water 

 to make five cubic centimeters, and then if you lose any of it, it 

 is an infinitesimal amount and will not affect the result at all; but 

 if you inject two-fiftlis of a cubic centimeter of crude tuberculin and 

 lose an infinitesimal amount of that, it does affect your dose unless 

 you give a double dose. 



The next thing is to inject the tuberculin into the cow with the 

 least possible annoyance to the cow. How are you going to do that? 



