DISEASES OF CATTLE 337 



those animals (less than 7 per cent) that do not receive sufficient im- 

 munity by this method and which succumb when exposed to infested 

 pastures. Combining these failures it will be seen that by this 

 method of immunization, instead of a loss of 90 per cent among 

 breeding stock taken South more than 90 per cent can be saved. 

 The animals should be carefully nursed through the attack and their 

 symptoms treated. 



Immunizing inoculations are now 'being made by the veterina- 

 rians of most of the agricultural experiment stations of the Southern 

 States without cost for the services rendered, a charge being made 

 merely for the actual value of food consumed and attendants' wages. 

 These veterinarians have also issued station bulletins which describe 

 fully the necessary steps to be taken in securing the blood and in- 

 jecting it into the animals to be immunized, so mat the stock owner 

 can follow the instructions with prospects of getting good results. 



This operation is not a difficult one, and excellent results will 

 follow where absolute cleanliness and ordinary care have been used, 

 but undoubtedly the best results will be obtained by those who have 

 thoroughly familiarized themselves with the nature of the disease 

 and are experienced in extracting blood from animals. Two meth- 

 ods are in use and will be described separately. One consists in 

 drawing the blood from the jugular vein of an immune animal and 

 immediately injecting it into the cattle to be immunized. It is com- 

 paratively simple, requires few instruments, and can be satisfactorily 

 carried out where a small number of animals are to be immunized 

 and if a suitable immune animal is close at hand. First, select an 

 immune animal which is in good health and which is infested with 

 fever ticks or had them the preceding year. Fasten the animal se- 

 curely, either by tying, throwing, or by placing in a chute. Clip 

 the hair from a space about 4 inches in diameter over the jugular 

 vein on the upper third of the neck, wash the skin thoroughly with a 

 5 per cent solution of carbolic acid, and then fasten a strap or rope 

 around the neck below the hairless area and draw it tight in order 

 that the blood in the vein will be stopped, causing distension. With 

 a large hypodermic syringe needle, previously sterilized in a 5 per 

 cent carbolic-acid solution, puncture the vein at a slight angle, direct- 

 ing the point forward. When the needle enters the vein the point 

 can be rotated freely in contrast to the restricted movements if still 

 in the tissues, and the blood will either drop or flow from the open- 

 ing in the needle. Attach the disinfected syringe to the needle with 

 piston in and gradually draw out the poison until the chamber of 

 the syringe is full of blood, when the needle is withdrawn. The 

 blood, before it has had time to clot, is immediately injected into 

 the animals to be immunized and which have been previously tied 

 or restrained, the hair clipped, and the skin disinfected at the seat 

 of injection in the region of the shoulder. Inject then from 1 to 3 

 c. c., according to the age of the animal, under the skin of each ani- 

 mal until the blood is exhausted. When more animals are to be in- 

 oculated than one syringeful will inject, the operation may be re- 

 peated in the same manner. The only objection to this method ia 



