50 



Mr. G. F. Dowdeswell. 



M. Pasteur. Salt solution or any other indifferent fluid would no 

 doubt answer as well, but bouillon has the great advantage of showing 

 at once the occurrence of any septic change in the fluid, by the 

 turbidity which it occasions. 



In order that the conditions of experiment might be strictly similar, 

 I have myself always used definite proportions of cord and bouillon ; 

 as 1 inch of the former, of an average-sized rabbit, weighs about 

 0"8 gramme, I have mixed or " diluted " this quantity with four times 

 its weight or bulk — their specific gravity being very nearly the same — 

 viz., 3*2 c.c. of bouillon. 



In order to free the infusion or " mash " thus prepared, from any 

 portion of the membranes investing it, or grosser particles of its sub- 

 stance unreduced, it is strained through fine muslin, sterilised by 

 passing over the flame of a spirit-lamp. 



In the earlier experiments with rabbits, the animal to be inoculated 

 was anaesthetised by aether ; it was soon found, however, that this was 

 unnecessary, inducing a great mortality, and being productive of pain 

 to the animal, whilst coming under and recovering from the influence 

 of the drug. I then used a solution of cocaine as a local anaesthetic, 

 with apparently satisfactory results, but ultimately found that nothing 

 whatever is required beyond the 5 per cent, solution of carbolic acid, 

 with which, after clipping the hair closely, the head is washed, as an 

 antiseptic ; if this is rubbed in for a short time, complete anaesthesia 

 is produced locally, the animal in the large majority of cases remain- 

 ing perfectly quiet, frequently with its eyes closed, daring the slight 

 operation of trephining and inoculation, and not requiring confinement 

 or restraint in any way, save by a hand lightly laid upon it. 



The bone is then trephined in the usual manner, a small incision 

 being made in the skin and periosteum, a little behind the coronal 

 suture, and on one side of the median line. The virus is injected with 

 a Pravaz syringe either between the bone of the skull and the dura 

 mater, or by perforating the latter with the curved point of the needle 

 the requisite quantity is injected into the sub-dural lymph space. 



The effect of either method is much the same, brt by the former 

 the incubation period is slightly but appreciably longer than by the 

 latter, the difference being, with intensified virus, one or two days. 



III. Symptoms and Post-mortem Appearances of Rabies. 



1. In the Dog. — These in the dog have been described by numerous 

 writers from the time of Caelius Aurelianus,* nevertheless considerable 

 misapprehension still generally prevails upon some points. The 



* ' De Morbis Acutis ' (Amsterdam, 1722). His account is short, but accurate in 

 most points, .and is the earliest extant. The period at which he lived is un- 

 certain. 



