502 BACTERIOLOGY. 



Inoculation for Rabies. 



The sac method of culture, as described, is not only use- 

 ful in increasing the virulence of an organism, but it possibly 

 affords a means of growing organisms that have hitherto 

 resisted all known methods of cultivation. It has already 

 enabled the isolation of the microbe of pleuro-pneumonia 

 an organism which is considerably smaller than any known 

 representative of , the group of bacteria. Undoubtedly, the 

 cause of other diseases such as small-pox, scarlet fever, 

 rabies, etc., will be found to belong to this class of extremely 

 minute microbes. 



The cause of rabies has not as yet been discovered, but 

 it is known to reside especially in the central nervous sys- 

 tem. It becomes important, at times, to confirm the diag- 

 nosis of rabies by injecting a portion of the spinal cord of 

 the suspected animal under the dura mater of a rabbit. For 

 this reason, the following method of inoculation, as prac- 

 tised at the Pasteur Institute is given: 



The rabbit is fastened, lying- on its abdomen, to a holder or to a 

 table by means of leather thongs or stout cords, and is anesthetized 

 with ether. The head of the animal should be turned toward a win- 

 dow. The excess of hair is removed from the surface of the skull 

 which is then moistened with carbolic acid or with lysol. An incision 

 about 3 cm. in length is then made. One flap of the skin is raised by 

 a pair of forceps and a jaw of a wire speculum is inserted. This is 

 done, likewise, to the other side and the speculum is then distended. 

 A trephine is applied to the exposed skull on one side of the median 

 line. The button, about 6-8 mm. in diameter is picked up and re- 

 moved by means of a hooked needle or tenaculum. 



A portion of the suspected medulla or cord has previously been 

 rubbed up by means of a glass-rod with water or bouillon in a test- 

 glass (Fig. 43, p. 265). The suspension is drawn up into a syringe and 1 

 or more drops are injected under the dura mater. A few drops of 5 

 per cent, carbolic acid solution are applied to the surface and are then 

 carefully removed with sterile filter-paper. This is repeated several 

 times, and finally, after drying the surface thoroughly, the speculum 



