132 



Dr. S. Monckton Copeman. 



[Xov. 13, 



attempts at variolation of the cow. Dr. de Haan's own words may be 

 quoted: — "Je reconnais qu'il manque a ma demonstration d'avoir 

 rapporte la variole mitigee du singe sur l'homme ; c'est une experience 

 que je ne me suis pas cru en droit de faire. L'experience de Chauveau 

 enseigne a etre prudent, et je ne me croirais autorise a faire cette 

 tentative que si le vaccin ordinaire dont je me sers me manquait au 

 moment d'une epidemic Mais j'espere qu'on repetera mes experiences 

 a ce sujet." 



For the purpose of his experiments Dr. de Haan made use of the 

 macaque monkey (Macacas cynomolgus), which is common in the 

 Dutch East Indies, and therefore was readily obtainable. His inocula- 

 tions were, in each instance, made on a portion of the animal's back, 

 which was first shaved and then cleansed with soap and water, 

 followed by a solution of boric and salicylic acids. In his first 

 series of variolations of the monkey, the small-pox lymph employed 

 was obtained from a Javanese child, no statement however being 

 made by him as to the age of the child, whether or not it had ever 

 • been vaccinated, or at what stage of the disease the lymph was taken. 

 Transferred to the monkey, this lymph gave rise, in a week's time, to 

 well-marked vesicles at the site of inoculation, while, in addition, 

 a few papules were observed on the lips and the extremities. Seven 

 subsequent primary variolations were, however, successfully carried 

 out on monkeys, in only one of which was any evidence of generali- 

 zation observed. 



From the contents of the vesicles of the monkey first-mentioned, 

 a second was inoculated, which in seven days developed vesicles at 

 the inoculated points only. From this second monkey, in due course, 

 a third animal was inoculated ; from this a fourth, and so on, through 

 a series of seven monkeys. 



From the sixth monkey of this series, a calf was inoculated, which 

 five days later presented an appearance indistinguishable from a 

 typical vaccination. From the seventh monkey also, of the series, 

 a calf was inoculated, with the result again, that after an interval of 

 five days, perfect vaccine vesicles appeared at the site of each insertion 

 of the lymph. From this calf another was vaccinated with complete 

 success. 



In a second series of experiments, lymph at the fourth remove, in 

 the monkey, from human small-pox, gave rise to perfect vesicles when 

 inserted on the skin of a calf, and the strain of vaccine lymph thus 

 obtained was carried on successfully, through eight removes from calf 

 to calf. Monkeys and calves all failed to react to subsequent inocu- 

 lation with the strain of vaccine lymph in current use. 



The results of my own experiments may be briefly summarised as 

 follows : — 



