154 SMALL-POX L\ SHKKl'. 



stages, and 1 could detect no difference between the 

 product of the pustules [P] a7id that of vaccine*." 



In his directions for the performance of the opera- 

 tion, Sacco states, that when we inoculate children, 

 or cows, with primary ovine lymph, it is advisable to 

 do so in six or eight places, as frequently not more 

 than one will take ; but the ichor which this yields may 

 always be relied on for future use. 



Similar experiments to those above mentioned have 

 been instituted both by Mr. Ceely and Mr. Marson ; 

 and, conjointly, these gentlemen have performed not 

 less than 250 inoculations with the virus of sheep-pox. 

 The first trial made by Mr. Marson seemed to indicate 

 the capability of the human subject to receive the dis- 

 order : the result, however, negatived the expectation, 

 and in every instance the attempts may be said to 

 have failed. In a letter received from Mr. Ceely, 

 April 9, 1848, that gentleman gives the following 

 valuable particulars on this subject : — 



" Human Ovinations. — I ovinated twenty-five sub- 

 jects, whose ages ranged from three to fifteen years ; 

 some twice and thrice over ; in none w^ere there fewer 

 than six punctures each time, making not less than 

 ISO punctures; no specific disease resulted; but a 

 prompt and devious papular or diffuse inflammation, or, 

 more rarely, a common local pustular. In the majo- 

 rity of these twenty-five individuals the virus employ- 

 ed was liquid. When very recently charged points 

 were used, subsequent re-inoculation with liquid virus 

 was had recourse to, but with no other effect. Near\y 



* Trattato di Vaccinazione, Capitolo9,p. 144 & seq. . ' 



