THERAPEUTIC IMMUNIZATION IN MAN 501 



Levaditi, 129 appear to support it. However, this is not of great im- 

 portance inasmuch as it determines merely a relative lengthening 

 or shortening of the period during which reinoculation or superin- 

 fection is possible. 



2. After the disease is well established as a systemic infection, 

 that is, from the time of development of the chancre throughout the 

 so-called active "secondary" period, reinoculation is either impos- 

 sible or, at any rate, extremely difficult. Neisser cites Rollet as 

 follows : 



"Although I and my predecessors have a thousand times attempted 

 to reinoculate luetic subjects, we have never observed a successful 

 case. I know no single fact more thoroughly proven than the insus- 

 ceptibility of a syphilitic to the action of a new virus, and, more- 

 over, these experiments are so harmless that they may be performed 

 without scruple." 



The same opinion was held by Mauriac and is in a general way 

 assented to by Neisser in his summary of this place of his studies. 

 (Neisser, loc. cit., pp. 180-181.) 



That the patient with well-developed lues has acquired a con- 

 siderable degree of resistance to fresh inoculations is pretty gener- 

 ally accepted, therefore, by all who have studied the question but 

 there are investigators, notably Finger and Landsteiner, who believe 

 this resistance to be less absolute than stated by earlier writers. 

 Their observations on patients with active syphilis seem to indicate 

 that superinfection is possible "under certain circumstances in all 

 stages of the disease," but "the positive effect can be obtained only 

 with considerable quantities of the virus." Furthermore, Land- 

 steiner 13 states that, in general, lesions so obtained are relatively 

 slight in severity, do not appear as primary indurations, but have 

 the tendency to simulate the particular variety of lesion spontane- 

 ously manifest in the individual at the time. Were it not for Finger 

 and Landsteiner 7 s monkey experiments, to which we will refer di- 

 rectly, and which seem to bear them out in their interpretation of 

 these inoculations as "positive" results, the simulation of the spon- 

 taneously occurring lesions by the inoculation-products would again 

 justify suspicion that these experimental results represented merely 

 traumata in which, as points of less resistance, the patient's pre- 

 existent disease had found a favorable spot for localization. 



Observations in this respect, also, are corroborated by the older 

 literature. A report which has direct bearing on this point, is one 

 oif Queyrat and Pinard who inoculated a tertiary patient with chan- 

 cre material, obtaining not a primary sore but an ulcerated lesion 

 having the clinical characteristics typical of the late skin manifesta- 



129 Levaditi. De I'lmmunite acquise dans la Syphilis. Ztschr. f. Imm. 

 Ref., 191, 277-318. 



130 Landsteiner. Centralbl /. Bakteriol, Ref. 190S. xli, 785. 



