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with the long diameter of the cells parallel to the axis of the 

 capsule. Dutrochet thought that by a sudden act of endosmose, 

 the fluid contents of the inner layer were transferred to the 

 outer, which becoming distended, the capsule exploded, scat- 

 tering the seeds about. Prof. Wyman found, that after the 

 outer layer of the cells had been shaved off the explosive power 

 of the capsule still remained. There would seem, therefore, to 

 be some other cause for the phenomenon in question, probably 

 a contractile power in the cells themselves ; a power no more 

 improbable in itself than that which produces ciliary motion. 

 Many capsules, when suspended for some time in the vapor 

 of chloroform, lost their explosive power ; others burst almost 

 immediately under its influence. 



Prof. Wyman also gave the results of his microscopic 

 examination of the structure of the brain and spinal chord 

 in Frogs. 



The transparency of the upper portion of the cerebral lobes in 

 these animals made it quite easy to examine their structure by 

 transmitted light. It had been recently maintained, by European 

 anatomists, that the essential elements of the structure of cerebral 

 matter are cells containing granules, and nerve tubes with which 

 the cells communicate by caudate appendices. In the frog's 

 cerebral lobes all the cells were destitute of an appendix, nor 

 a single nerve tube except near the base. He had observed a 

 few lines resembling nerve tubes, which he considered capilla- 

 ries. The optic lobes contain both cells and nerve tubes, but no 

 connection between them was noticed. 



In the end of the tail of the Tadpole the minute structure of 

 the spinal chord was quite apparent. In the middle of the 

 chord cells and transverse and longitudinal fibres were quite nu- 

 merous. Towards the end, however, the transverse fibres gradu- 

 ally disappear, leaving only cells and lateral nerve fibres, the 

 latter also diminishing in number, and at last leaving only cells. 



Dr. Burnett stated, that he had carefully examined the human 

 brain to discover, if possible, the structure described by Wagner, 

 alluded to by Prof. Wyman, but without success. 



Prof. Wyman remarked, that Kolliker and others have made 

 out the structure described by Wagner in some of the Annelids. 



