Royal Society. 383 



of a highly pellucid substance, originally having little if any colour." 

 This substance, which he considers as being primogenital and form- 

 ative, he denominates hyaline, and ascribes to it the following pro- 

 perties. It appropriates to itself new matter, thus becoming enlarged ; 

 then divides and subdivides into globules, each of which passes 

 through changes of the same kind. Under certain circumstances, 

 it exhibits a contractile power, and performs the motions called 

 molecular. It is the seat of fecundation, and it is by its successive 

 divisions that properties descend from cell to cell, new properties 

 being continually acquired as new influences are applied ; but the 

 original constitution of the hyaline not being lost. The main pur- 

 pose for which cells are formed is to reproduce the hyaline ; and 

 this they do by effecting the assimilation which prepares it to 

 divide ; such division being thus the essential part of fissiparous 

 generation. 



The remaining part of the paper is occupied with a detailed ac- 

 count of these processes as they occur in the development of the 

 ovum, and also in the changes exhibited by the corpuscles of the 

 blood, in which fissiparous reproduction also takes place, and the 

 red blood-discs are converted into fibrin, and thus give origin to 

 the various tissues of the organs. The same theory of fissiparous 

 reproduction he also applies to the formation of the muscular fibre, 

 in connexion with his belief that it is composed of a double spiral 

 filament. Contractile cilia, he supposes, are also formed by the 

 elongation of nuclei, the filaments proceeding from them in opposite 

 directions. The author considers, lastly, the subject of the fissipa- 

 rous reproduction of the Infusoria, and particularly of the Volvox 

 globator. the Chlamido-monas, Baccillaria, Gonium, and the Mona- 

 dina in general ; and applies the same theory to gemmiparous repro- 

 duction, and to the so-called spontaneous generation of infusoria and 

 parasitic entozoa. 



March 16. — " Further Observations on the descending fluids of 

 Plants, and more especially the Cambium." By George Rainey, Esq. 

 Communicated by P. M. Roget, M.D., Sec. R.S. 



The author relates an experiment in 'proof of the sap descending 

 from the upper to the lower part of an exogenous tree, through vessels 

 which are continuous from the leaves to the roots ; the course of 

 these vessels being shown by the addition of a solution of iodide of 

 potassium after they had taken up by absorption a quantity of a 

 solution of acetate of lead. The fluids in these vessels are, he con- 

 ceives, separated from the sap, which is ascending from the roots, 

 only by the membrane of which they are composed. When the 

 leaf-buds of a tree are vegetating, large separations are observable 

 between the cells of the bark, and also between the bark and the 

 wood ; while no such separations are apparent when the leaf-buds 

 are entirely inactive. These separations are various in size, and 

 irregular in form ; their parietes consist of rows of cells, piled up 

 one above another, like the bricks of a wall : and their cavities all 

 communicate with one another. From these and other anatomical 

 facts, which are given in detail by the author, he concludes that the 



