MANUFACTURE OF HOG-CHOLERA SERUM 



339 



across the large blood-vessels and catch the blood in clean bottles 

 as it escapes from the wound thus made. A somewhat more 

 cleanly method is to introduce a hollow metal or glass tube into 

 the blood-vessel and allow the blood to flow through this tube. 



Fig. 60.— Bleeding for virus. (Photo by Dr. Geo. R. White.) 



In either case the operator is provided with large-sized bottles 

 or small buckets, which have been thoroughly washed and further 

 freed of germs by steriHzation in an oven. Into these clean, 

 germ-free containers the virus blood is allowed to flow. Every 

 precaution is observed to see that no dirt enters the vessel with 



