Analgesia in Cats after Exposure to War Gas. 105 



In such animals severe operations may be performed without 

 any anaesthetic and without eliciting any or only slight indications 

 of pain. Thus, for example, the femoral artery may be dissected 

 free, tracheotomy performed, the vagosympathetic trunk exposed 

 in the neck, the tibialis anticus muscle dissected free, the periton- 

 eum opened and the parietal walls rubbed by an inserted finger, 

 or gentle traction exerted upon the gut, without causing any or 

 at most only slight signs of pain. Severe compression of the tail, 

 toe pads, nasal septum, lip, ears, cause no sign of pain, though the 

 tail is twitched aside, the foot withdrawn, the head turned away 

 or the ears flattened against the head when the pressure stimulus 

 is stopped. 



The loss of pain perception was, however, not complete in 

 any animal : blunt dissection of a mixed nerve which stretched it 

 or electrical stimulation of the sensory nerve, always caused more 

 or less restlessness of the animal, but never to the degree which is 

 obtained by the same manipulation in a partially anaesthetized cat. 



There is therefore not only an outspoken depression of the 

 peripheral apparatus for pain perception, but the higher centers 

 show also a definite though less marked involvement. 



It must be emphasized that the analgesia described above does 

 not depend upon a low general state. There may be a profound 

 general analgesia while the animal is in an excellent general condi- 

 tion; thus in an instance with most pronounced analgesia the 

 blood-pressure was 118 mm., pulse 150, respiration 35 per minute; 

 the tongue and mucous membranes showed a good red color, and 

 the rectal temperature was 37. 3 0 C. 



While investigating this analgesic property of dimethyl sul- 

 phate gas, Naiding published observations in the Russky Vrach 

 (May 6, 13, 20, 1917, XVI) recording the production of local or 

 generalized skin analgesias in soldiers gassed with chlorine and 

 phosgene. Naiding appears to have tested skin sensibility only 

 and does not mention that severe cutting operations can be carried 

 out without pain. In experiments which are at present being 

 carried out with another exceedingly toxic war gas the same re- 

 markable analgesia is produced. Analgesia may thus be produced 

 by at least three widely different war gases and may perhaps be 

 a property of most gases usable for military purposes. 



