No. 5. DEPARTMENT OF AGRICULTURE. 297 



By usiug a small, sliaif) needle, and see that your needle is always 

 sharp before introducing it into the cow. I have, in many instances, 

 had my attention called by the cow itself to the fact that the needle 

 was dull; I knew the needle was dull from the way the cow acted, 

 and upon examination I found that was the case, and, therefore, 

 used a new needle. So you want to have a good supply of real good, 

 sharp, small needles, not a large needle, and you can go right along 

 with very few exceptions, where you have fractious cows. Of course 

 when you inject into a cow, she will pay no attention to you if she is 

 familiar with you herself, or she will pay very little attention to 

 you if you are dressed according to the habit of the barn, and it is 

 a matter of very little work to inject. 



The next thing to do is to have a good syringe, a syringe that don't 

 kick, a syringe that don't leak, a syringe that has not laid on the 

 shelf a long time and dried out, one that when you use a little pres- 

 sure on the piston to force out the tuberculin, it don't kick back 

 so that you can't tell how much you are giving. Now I should have 

 mentioned before about taking the temperature before the injection. 

 Of course you have got to take temperature and take them sufficiently 

 long to determine the mean normal temperature of the animal, and 

 you want to take temperatures at times of the day corresponding 

 with the temperatures the next day so as to compare them and note 

 any difference. If you should only take a night temperature before, 

 we will say, and run along until the next night, you are not able 

 to compare the temperature before and after at the same time, so 

 it is always best to take the temperature in the morning, take the 

 temperature at noon and take the temperature at the time of your 

 injection; and if you can take it oftener than that, why so much 

 the better. 



Now the question comes, the most important part of the whole 

 thing appears, and that is the after-temperatures, the temperatures 

 following the injection of tuberculin. You know that if a cow is 

 tubercular, you expect a rise in temperature; I am not going into 

 the details or the technique of this, because T might get too deep 

 in the bacteriological side of it, therefore I will keep out, myself. 

 This tuberculin is injected into the cow for a certain reason. What 

 is it? That reason is that that tuberculin is supposed, when in- 

 jected into a cow affected with tuberculosis, to create a systemic 

 disturbance of some sort. That disturbance is evident to a more 

 or less degree by an elevation in temperature. Now I want to say 

 right here that it does not make any difference to Avhat degree that 

 temperature goes, if it goes up at all, if it goes up a degree, there 

 is some cause for it; and if you cannot find any other cause than 

 tuberculosis, it is tuberculosis and you have got to figure that it is 

 tuberculosis. 



Now just how long do you expect it to be before you get a re- 

 action? Well, I might qualify that by saying: How long would 

 one expect before he gets the maximum elevation of temperature or 

 reaches the height of the reaction, so to speak, because it's got to 

 go up? It may surju'ise you to know that T have seen that at the 

 twenty-fourth hour, and only the other day I noticed one the twenty- 

 second hour. The temperatures were absolutely normal up to the 

 eighteenth hour. The twentieth hour there was a little movement 

 of the thermometer in an upward direction. It continued and we 

 eighteenth hour. The twentieth hour there was a little movement 



