DAIRY MEETING. 1 01 



tive property is only demonstrated in the younger animals. It 

 is for this reason that it is not necessary to test animals under 

 tliree months of age. The producing of the immunity consists 

 of two inoculations, with an interval of three months between 

 them, the second inoculation being five times the strength of the 

 first. The animal is prepared for vaccination by clipping the 

 hair from the jugular vein near the base of the neck and disin- 

 fecting the area. The vaccine is prepared and is drawn up into 

 the barrel of the hypodermic syringe. The operator inserts the 

 needle into the vein, and waits until there is a satisfactory flow 

 of blood to be sure that he has properly reached the vein. Then 

 he introduces the vaccine., with the syringe, slowly into the cir- 

 •culation, throwing it against the current of the blood so that it 

 will be divided and evenly distributed and not go in in one bulk. 

 The germs thus introduced into the circulation are slowly but 

 surely absorbed or destroyed, the process taking several months. 

 Hence the interval between the two inoculations. So long as 

 unabsorbed germs are present, which after the second inocula- 

 tion may be for several months, there will be a sensitiveness to 

 tuberculin injection in these animals. The immunity produced, 

 ■even a few months after the second inoculation, is so strong 

 that it requires ten times the amount of virulent tuberculous mat- 

 ter which is fatal to the unvaccinated animal to have the slight- 

 est effect on the vaccinated one. Numerous experiments have 

 "been conducted at experiment stations in Connecticut, New Jer- 

 sey, Maryland, Minnesota, California and Virginia, and at the 

 present time the State Veterinarian of Minnesota will admit 

 vaccinated animals into the State without a tuberculin certificate, 

 and he is introducing a bill into the State legislature to appro- 

 priate $5000 for the purchase of bovo vaccine, to stamp tuber- 

 culosis out of their herds. Over 70,000 head of animals have 

 Ijeen vaccinated, and there have been no unfortunate results. 

 In these experiments at the stations animals have been used to 

 check the results. For instance, six or seven calves are vac- 

 cinated and six or seven more tested and found not to be infected 

 with the disease, and both lots are subjected to the same con- 

 ditions. They have been fed tuberculous matter, they have had 

 it injected into the jugular vein and had it introduced under the 

 skin. After a certain length of time both sets of animals have 



