212 Notice of some Recent [March 



in the upper part alight tar-oil, in the middle an acid liquid, 

 and at the bottom a heavy oil. The latter is to be distilled 

 a second time, and when the matter becomes scaly, the 

 receiver should be changed, and the heat increased until 

 the residue becomes black and thick. In the receiver, 

 which is filled with a yellow vapour, an oily liquid appears, 

 in which spangles of paraffine are observed. From this 

 liquid, which, if it does not exhibit the characters described, 

 must be again distilled, the paraffine may be obtained by 

 the following methods : — Mix it with from six to eight times 

 its weight of spirit of wine, (sp. gr. -837.) In a short space 

 a thick liquid separates, which must be again washed with 

 spirit of the same strength, till it is converted into colour- 

 less thin portions, then these are to be dissolved in hot 

 absolute alcohol, and the solution allowed to cool. This 

 process may be repeated until a snow white precipitate of 

 paraffine is obtained. (Pogg. Ann.) 



ANIMAL SUBSTANCES. 



Structure of the Nerves and Brain, {Pogg. Ann. xxviii. 

 463.) — According to Ehrenberg the cerebral mass consists 

 of parallel tubes expanding in a varicose manner, and con- 

 verging to the base of the brain. The brain is a system of 

 capillary vessels similar to the nerves. The nerves of sen- 

 sation and the sympathetic nerve consist of soft, cerebral, 

 medullary matter ; the latter surrounded by nervous tubes. 

 These may be termed jointed nerves (nerves of sensation? ) 



All other nerves consist of tendinous, cylindrical tubes, 

 formed of a peculiar medullary matter, which may be called 

 tubular nerves, (nerves of motion ?) 



The nervous medullary matter is absent in the brain 

 and jointed nerves. 



The structure is the same in man and all vertebrated 

 animals. In the inferior vertebrated animals, the soft, 

 cerebral matter is observed in small quantity, while the 

 tubular substance is abundant. 



In the vascular net of the cortical substance of the brain, 

 large globules are scattered, which are proportional to the 

 globules of the blood. 



By the aid of powerful instruments, Krause has been 

 able to observe in the cerebral and nervous substance small 



