122 S.MALl.-POX IN SFIF.KI'. 



Twclftli day. — The cuticle covering tlie inoculated 

 places has a yellow hue, and looks as if it would des- 

 (piamate without vesication. All symptoms of the 

 eruption have passed off. 



Fourteenth day. — It is evident that sloughing will 

 take place around the incisions. 



Sixteenth day. — The vitality of large portions of the 

 dermis has been destroyed, and their separation has 

 commenced. 



Twentieth day. — Extensive sloughs have been 

 thrown off; the ulcers however look healthy. 



The great liability of the inflammation of the inocu- 

 lated places to produce ulceration is undoubtedly dis- 

 advantageous, and must prove an obstacle to the 

 extension of the ovination. Whether sloughing would 

 follow the use of lymph which had been passed through 

 the systems of a number of healthy sheep in succession, 

 can only be ascertained by diversified and well-arranged 

 experiments. Primary lymph is e\ddently too virulent ; 

 and some plan to mitigate its local effects must be 

 devised before inoculation can become general. The 

 statements of the continental wiiters are contradictory 

 with reference to the change which takes place in the 

 lymph by transmission from sheep to sheep. Some 

 maintain that it destroys its specific properties, so that it 

 no loncfcr induces a disease which will secure the animal 

 against the small-pox ; while others contend that, after 

 several transits, a lymph equally as protective, but far 

 less virulent, is produced. Mr. Mayer, in an article 

 chiefly translated from Hurtrel D'Arboval, and to which 

 we have before referred, states, that " after the same 

 matter [lymph] has passed through twelve or fifteen 

 lots of sheep, it loses its efficacy, and requires to be 



