CANKER IN SNAKES KEPT IN CAPTIVITY. 215 



out of twenty I had from this complaint. I was then 

 advised to substitute soft filtered water for the hard 

 unfiltered. This I did, and for three years I have not 

 lost a single specimen from this cause. From this I 

 think there is reason to connect the water with the 

 canker. Strange to say, the disease does not occur in 

 snakes in their wild state. 



" The symptoms, taken from the examples which I 

 have had in my own collection, are as follows : — 



" The mouth of the snake generally seems to get 

 filled up to a greater or less extent with a kind of 

 fleshy substance. The eyes frequently increase in 

 size, and sometimes turn quite white and opaque, 

 though this latter symptom is rather exceptional. 

 Then gradually the head and neck swell up, some- 

 times to such an extent that the scales become 

 stretched apart. The snake in the mean time refuses 

 to eat or drink. There is no outward sign of any other 

 part of the snake being affected except the head and 

 neck. The reptile may linger in this condition for a 

 considerable time, although most of my specimens that 

 were affected have died in two or three weeks. 



" The disease is highly contagious, in proof of which 

 I may cite the following cases. I received a perfectly 

 healthy specimen of the dice snake (Tropidonotits tes- 

 sellatus), which I placed in a new vivarium which had 

 only just been made, and consequently had never pre- 

 viously contained snakes. The dice snake remained 

 in a healthy condition for two or three weeks, when I 



