1815.] of the Effect of Ice on a Thermometer. S45 



plienomena of his experiment, but appears to have been misunder- 

 stood. Still it involves some strong improbabilities; while that of 

 Prevost, if we only admit certain analogies (some of which we 

 know exist) between the radiation of heat and tliat of light, is even 

 df monstrable. I was about to add a comparison between these two 

 tlieories ; but I have already made my letter much longer than I 

 intended. 



Article VI. 



On the Cerelellum. By W. Elford Leach, M.D. 



(To Dr. Thomson.) 



MY DEAR SIR, 



In the last number of your Annals of Philosophy Mr. A. Walker 

 claims the merit of being the discoverer of what Dr. Cross has 

 stated respecting the structure of the spinal marrow and the use of 

 the cerebellum. He has at the same time answered my letter to 

 Dr. Cross, and has stated that the work of Gall and Spurzheim 

 " actually contains no such statements " as those to which I 

 alluded. 



Permit me. Sir, to assure you that the letter from Hufeland to 

 Portnl contains precisely the same opinion respecting the use of the 

 cerebellum as that given by Mr. Alexander Walker and by Dr. 

 Cross.* 



When I perceived Dr. Cross's observations on the anatomical 

 structure of the spinal mass of nerves, I recollected that in the 

 work of Gall and Spurzheira the same statements were given, not 

 as existing in nature, but as erroneous suppo^^itions. In the folio 

 edition of their Anatomic et Physiologic du Systeme Nerveux en 

 g(^'neral, vol. i. p. .35 and 40, the following statements may be 

 found: — " Bartolin says that the spinal marrow is composed of four 

 fibrous cords;" — " Soemmerring maintains the opinion that the 

 spinal marrow is composed of four cords." f 



My oliject in answering Dr. Cross was merely to show that 

 although his 0])inion might have been original, yet that the same 

 opinion had been entertained by preceding writers. Since writing 

 that answer, I have carefully examined the structure of the spinal 

 mass of nerves; and I most ccriainly agree with Drs. Gall and 

 Spurzheim in maintaining that the spinal mass of nerves does not 

 consist of " four columns," and that Mr. A. V\'alker merely parti- 

 cipates in an error common to older writers in maintaining this 

 opinion. 



• Willis likrwisf roiibidrrcd llip rercbelliim an the source of volniilary power. 

 •♦• Ilif^hiMur'- oven goes furtlur: he i)ieteiid!i that the spinal niiinow h I'oruied of 

 right Hide curdi. 



