38 



Generally the fits last from five to fifteen minutes. The 

 stronger they are the shorter is their duration. For an hour or 

 two, and sometimes for one or two days after a violent fit, it is 

 impossible to produce another one by any kind of excitation. 

 When a fit takes place a short time after a violent one, it is 

 always weak or very short. 



I have made the following experiment on some guinea-pigs 

 having this convulsive affection : I put them in a small box, so 

 that they had but little room to move, and I gave them food 

 in great abundance. They then ate very much and were 

 deprived of exercise, and, in consequence of that mode of living, 

 they had exceedingly frequent convulsions. One of them had 

 a fit nearly every quarter of an hour. These fits sometimes were 

 strong, but they did not last long. The others had fits three or 

 four times every day. I changed their mode of living, and 

 put them all in a large room where they had only a small quan- 

 tity of food. The influence of this new regimen was nearly 

 immediate ; the same day the number of fits was diminished, 

 and in the course of the third week afterwards they had only 

 one or two fits ; and before long some of them were cured. 



I must relate also a very interesting fact analogous to the 

 preceding. In several guinea-pigs and frogs, which had the 

 spinal cord transversely divided, I have observed that when the 

 animals remained very quiet during many days, instead of the 

 regular reflex movements, they had a violent tetanic convulsion 

 in their posterior limbs, when the skin of these limbs was 

 pinched. 



Such a tetanic movement never occurred in these animals 

 when I excited the regular reflex movements every day. 



I have no room in this resume to try to explain the facts 

 related ; I will do it in a special paper. I will only add that all 

 the readers of this note, who know the views of Dr. Marshall 

 Hall about convulsive diseases, will remark how strongly the 

 facts I have pointed out are confirmatory of these views. 



XV ON THE RELATIONS EXISTING BETWEEN THE ORGANISATION 



OF NERVE TUBES AND THEIR VITAL PROPERTIES. 



It is well known that when the nerve tubes are examined in a 

 very fresh state, their contents, the medulla^ or white substance of 



