INVESTIGATING ORGANIC FORMS. 209 



be taken. Was it not po.s.sible, by ascertaining the accurate 

 shape, the forui and proportion between the parts, organs, and 

 whole body of any animal, to advance the study geometrically? 

 Suppose the anatomist gave the exact cui-vature of the surface, 

 the volume and proportions which different parts of the organs 

 might bear — what their formal geometry was might liecome 

 matter of calculation. lie might begin, by the lengths, and 

 breadths, and volumes of the ditlerent parts, Ijy ascertaining 

 whether they have a correspondency, and exhibit a mathema- 

 tical relation, spherical or spheroidal curves, etc. These once 

 ascertained, he woiUd become tsertain of the geometrical con- 

 struction, and could reason as to the probable forms of other 

 parts. 



Impossible as it might appear, this had been effected in 

 certain instances, and esi)ccially in a most beautiful manner 

 in regard to shells of molluscous animals, by the Reverend 

 Professor Moseley, late of Cambridge,* who had made an exact 

 geometrical examination of shells, and especially of the Tur- 

 bines, which were possessed of a spiml curve woimd round a 

 central axis, which ciirv'e had been found to be logarithmic, and 

 from it had been framed a series oi formula:, by which the other 

 conditions of the shell could be predicted and foimd to exist. 



By a very accurate measurement of the shell, mathemati- 

 cally, it was foimd that its spii-es increased in breadth in an 

 exact successive series, each one of which was a multiple, in 

 a certain ratio, of another. Thus there was a mathematical 

 principle arrived at, which could be can-ied out — the shell 

 must possess tliis form, and could possess no other. It had 

 a spiral cune, and the properties of that ciutc pointed it 

 out to be a logarithmic curve, one which would reproduce 

 itself; a curve formed by a thread wound off the exterior, 

 would trace the form of its opercidum ; and the mf)uth of 

 the animal was remarkable for geometrical symmetiy. As 



• Philosophiail Tran.tticlitnui, 1S3S, \t. 351. 

 P 



