288 INFECTIVE DISEASES. 



introduce it by puncture, obliquely, between the scarf and true skin, 

 barely sufficient to draw blood, and not deeper than the sixteenth part of 

 an inch. Neither patting, nor daubing of the matter, in or over the 

 punctured part, is at all necessary to its efficacy. This practice, indeed, 

 is rather prejudicial than otherwise, as it may affect the form of the 

 incision, and thus be apt to confound our judgment upon it. 



" Indications of the Incision. — In the incipient state of variolous 

 increase in the incision, a small florid spot appears on the part of access, 

 resembling a flea-bite in size ; and on passing the finger lightly over it a 

 hardness is felt not larger than a small pin's head. This florid appearance 

 and hardness denote that the variolous principle is effectually imbibed, 

 and their indications point no farther, unless the progress to vesication 

 be very slow, in which case an uncomfortable number of pustules may be 

 expected to follow. The florid spot in most instances of inoculation is 

 somewhat larger, or more extended on the second, than on the third day 

 after the insertion. 



"About the fourth day from inoculation, should the incision begin 

 to vesicate, an itching sensation wiU be complained of on the place of 

 insertion — the occurrence of which symptom is the first indication of a 

 favourable event, yet not of sufficient importance to justify any present 

 relaxation in the preparatory proceedings. 



'' The vesication of the incision in most instances will begin to be visible 

 on the fourth or fifth day after the insertion of the matter ; the sooner 

 it becomes so, the more favourable may be expected to be the event. The 

 extent or diameter of the vesication at this stage does not usually exceed 

 that of a large pin's head, and it has invariably a dint or small depression." 



Adams obtained still more striking results by inoculating with 

 variolous lymph from pearl-pox, a mild variety of small-pox. Starting 

 vdth lymph obtained from this benign form of small-pox, and 

 selecting the cases, and carrying on arm to arm variolation, the 

 results obtained were practically identical with the phenomena 

 obtained by inoculation of the arm with cow-pox lymph. Similar 

 results were obtained by Guillou, but more rapidly. In 1827 there 

 was an epidemic of variola, and Guillou, having no vaccine virus, 

 took variolous lymph from a girl fifteen years of age on the fifth day 

 of the eruption. The case was one of varioloid or mild small-pox, attri- 

 buted to previous vaccination. The variolous lymph was inserted in 

 ten places on the arm of a healthy infant still at the breast. This 

 inoculation produced ten beautiful " vaccine " vesicles, from which, on 

 the ninth day, forty -two infants were inoculated \inder the eyes of 

 two of the local authorities. These furnished virus for the inoculation 

 of one hundred, who were inoculated in the presence of magistrates 

 and many medical men. This experiment was repeated with success. 

 Variolous lymph was taken from tvro lads at school, and in ten 



