252 Royal Society : — 



mixture was made of pounded ice and common salt ; the temperature 

 by it was commonly reduced to below 10° Fahr., or at times so low 

 as 2° or 3°. The results obtained were briefly the following : — 



1. A leech was exposed to the mixture in a small glass tube just 

 large enough to hold it, using the tube for stirring the mixture. 

 Taken out when perfectly rigid and hard, and gradually thawed, 

 it showed when punctured a faint indication of irritability ; there 

 was a just perceptible contraction of the part punctured, the oral 

 extremity, and nowhere else. It did not revive. 



2. Another leech was similarly exposed, but for a shorter time. 

 When divided by an incision, it was found not frozen throughout. 

 When punctured, it showed marks of irritability in a slight degree 

 stronger than the preceding : it soon died. 



3. Two leeches were similarly treated at home, and for a some- 

 what longer time, the temperature reduced to 3°. These, when 

 gradually thawed, one exposed to the air, the other left in the mix- 

 ture, showed no marks of revival ; but they retained a certain elas- 

 ticity, so that when bent they shortly recovered their former attitude, 

 after a manner somewhat resembling a vital movement ; but inas- 

 much as they did not respond by the slightest contraction to punc- 

 ture, it may be inferred that the movement was not vital. They 

 resisted putrefaction for many days. 



4. A frog in a thin glass vessel was kept in the mixture about a 

 quarter of an hour. It was very rigid when taken out ; thawed, no 

 part, on puncture, afforded any indications of life ; watched two or 

 three hours, it proved to be dead. 



5. The heart of a frog, removed immediately after decapitation, 

 whilst still pulsating, was subjected to the freezing- mixture in a 

 small glass tube. After having been frozen, on thawing it remained 

 motionless, even when punctured. It had been kept in the mixture 

 only a few minutes. 



6. The inferior extremities of a frog kept extended by a bandage, 

 and thus introduced into a glass tube, were submerged in the mixture, 

 the body of the frog being held in the warm hand ; taken out after 

 some minutes they were quite hard and motionless, whilst the body 

 and upper extremities did not appear to be affected. It moved 

 about, dragging the lower extremities as if they were def.d. In about 

 four hours it recovered the use of its femoral muscles, on the fol- 

 lowing day the use of the muscles of the legs ; the day after, it was 

 able to bend and extend these limbs ; but there was no proof that its 

 feet had recovered sensibility. On the fourth day it was found dead. 



7. The lower extremities of a large toad were immersed in direct 

 contact with the mixture, the temperature falling to 3°. Gradually 

 thawed, the parts showed no marks of life. This toad, which before 

 the trial was in a dull state, afterward became almost torpid, and so 

 continued until the following morning, when it was apparently dead : 

 Opened, the auricles were found feebly acting, ceasing after a few 

 seconds*. 



* This toad was a female which had shed her ova ; the oviduct was still large ; 

 the stomach was distended with caterpillars, slugs, &c., seeming to show that 



