222 NATURAL 8CIENCE [April 



perfect state in the caves ; no evidence of the use of even a rudi- 

 mentary potter's wheel is forthcoming. Stone and shell implements 

 necessarily form an important series referred to in the paper, but the 

 forms described are for the most part well known, though a few 

 rarities are recorded. The paper also deals with the human-form 

 grotesques, of which a few have been found in the island, and refers 

 to a few interesting rock carvings and petroglyphs which remind one 

 of examples from other islands of the West Indies and from the 

 mainland. 



The map at the end, showing clearly the position of the already 

 ascertained ancient remains, is well done, and should prove very 

 useful. We can heartily wish success to the Museum authorities in 

 their work of collecting and collating the available local material. 

 It is to be hoped that collections both from the other neighbouring 

 islands and from the mainland region of Guiana may be associated 

 with the Jamaica finds, in order that further light may be thrown 

 upon the past history of a most interesting race. If this is well 

 carried out, this museum will have fulfilled a duty of very high 

 importance. 



A Paeallel between Chemical and Vital Phenomena 



When a saturated solution of a crystalline substance is allowed to 

 cool below the saturation point, the dissociated molecules dissolve 

 their partnership with the fluid and slowly build up the structures 

 we know as crystals. There are, however, a number of curious con- 

 ditions of this process. In some cases, if the solution be kept 

 absolutely still, no crystallisation occurs, but a slight jar, or stirring 

 with a wand, apparently miraculously transforms the liquid into a 

 mass of crystals. In other cases, it is necessary, or at least 

 advantageous, that some foreign granules of dust, or threads of cotton 

 be present, to serve as nuclei around which the forming crystals 

 cluster, as the layers of nacre in a shell-fish transform an intruding 

 grain of sand into a radiant pearl. But most curious of all are the 

 cases in which an almost necessary stimulus is the presence of an 

 already formed crystal of the crystalline salt. The analogy between 

 this and the processes of life stares at one. One fluid may contain 

 all the ingredients for the building of crystals, but the crystals 

 refuse to form until a formed crystal is dropped into them ; another 

 fluid may contain all the necessary food materials for the building 

 of protoplasm, but it remains barren of life until a spore, a tiny mass 

 of protoplasm, has reached it, and then at once the building of proto- 

 plasm begins and proceeds apace. Such comparisons have been 

 made, and are worth making, if it be remembered that they are 

 things of the dreamland, of the after-dinner meditative hours of 



