254 Letter to the President from Col. Walker, E.E., F.R.S., 



give it support, such as the opacity of the crystalline lens, he admitting 

 that, were it possible for an animal to revive after complete congelation, it 

 would be blind from cataract ? Now, if the crystalline lens, if the blood- 

 corpuscles suffer and undergo an appreciable change from congelation, it 

 would be very remarkable indeed did not the brain and nerves, and the 

 organs generally suffer from the same cause, and experience c*hanges in- 

 compatible with life. In the instance of man, we know that a certain re- 

 duction of his temperature merely, not reaching to congelation, suffices to 

 extinguish life *, and that in the instances of other animals, especially the 

 hybernating and insects, a moderate reduction occasions torpor, ending in 

 death if too prolonged. That the organs generally suffer from congelation 

 M. Puget himself admits, as expressed in the subjoined paragraph f. I 

 have found, too, that the muscles, after having been frozen, exhibit a 

 marked change ; thus, in one instance, that of a frog, in which, after de- 

 capitation, an upper and lower extremity were frozen, the muscles of these 

 limbs, when thawed, compared with those which had not been frozen, 

 showed a well-marked difference under the microscope. Thus, whilst in 

 the latter the striated structure was very distinct, in the former it was no 

 longer visible ; and after a few hours, viz. on the following morning, 

 whilst the unfrozen muscles had undergone no perceptible alteration, those 

 which had been frozen had become of increased tenderness, yielding to a 

 slight rending force, and breaking short, as if the coherence of the particles 

 forming the fasciculi was greatly diminished. 



II. " Letter to the President from Lieut. -Colonel Walker^ H.E., 

 F.R.S., Superintendent of the Trigonometrical Survey of India.''^ 



Dehra Doon via Bombay, 31st May, 1866. 

 My dear General, — Captain Basevi has just returned to my head 

 quarters, on the close of the operations of his first field-season with the 

 pendulums. 



You will be glad to hear that his progress has on the whole been very 

 satisfactory. At the outset he met with numerous difficulties ; the 

 v acuum apparatus was very troublesome, the air-pump constantly getting 

 out of order, and the receiver as constantly leaking. It is very easy for 

 philosophers to suggest improvements and refinements in the modus 

 ojperandi of such operations, but it is not so easy to carry them out prac- 

 tically. Capt. Basevi has undergone a great amount of labour and 

 anxiety, but he has successfully surmounted all his difficulties. 



* Instances have occurred in the Lake District of persons who have jjerished on the 

 hills from prolonged exposure to strong wind and rain, storm-striclcen, in the language of 

 the country. 



t "... La congelation complete a meme si profondement altere les tissus de I'or- 

 ganisme que quand 1' animal est tout a fait degele, son corps est flasque et mou, ses 

 cristallins sont blancs et opaques, et souvent sa coloration est tout a fait alteree " (p. 24). 



