RA1NEV, ON STARCH GRANULES. i) 



lieving that the chemical and meehanical conditions which 

 were employed in the experimental process for obtaining them 

 existed in the animal organization, and therefore that both 

 kinds of carbonate globules were of the same structure and 

 produced under the influence of the same agencies. 



Fig. 9 is a representation of some of the largest kind of 

 artificial globules joined together, and in progress of coales- 

 cence to form a single one, just as those represented by 

 fig. 8 are; and, doubtless, the globules of starch in figs. 6 

 and 7 are in a like condition of coalescence. 



I will now proceed to the second part of this paper, that 

 is, to show that chemical and mechanical conditions similar 

 to those in the experimental process for obtaining carbonate 

 of lime globules, and which are necessary, on the same prin- 

 ciple, to produce these several forms of starch, exist in the 

 vegetable organization. This I look upon as the most novel 

 and important part of this communication. 



Now, as it is a fact generally admitted, that vegetable 

 membrane is impermeable by solids, however minute may be 

 their particles, it can only be in the interior of the starch- 

 cells that starch can receive its solid form. Hence, there 

 must exist in solution in these cavities some fluid capable of 

 furnishing starch, or from which starch can be precipitated 

 on the access of a second fluid containing some one or other 

 of the constituents of starch in solution. Now, Avith respect 

 to the first solution there will not be much difficulty, as 

 dextrine — " a soluble substance found in almost all parts of 

 plants" — or some solution analogous to it, will fulfil this— the 

 first — condition. And as respects the second, the difficulty 

 is still less, as there is no known solution but that of gum, 

 which is diffused generally through plants. Hence, if starch 

 be produced upon the principle of precipitation, from a fluid 

 within the starch-cell, as the globular carbonate, and the mixture 

 of globular carbonate with phosphate of lime are in the hard 

 tissues of animals, there is no other solution but that of gum, 

 which, from its general diffusion in the tissue of these cells, 

 can precipitate it. Now, to show that these substances, under 

 the circumstances they exist in vegetables, will perfectly fulfil 

 all the conditions necessary for the formation of starch in the 

 cells of plants, I will give some out of the many experiments 

 which I have made for that purpose. 



I will first show that gum possesses some remarkable pro- 

 perties which, I believe, are entirely unknown both to che- 

 mists and physiologists. One of these properties is its action 

 as a general precipitant of substances contained in solution 

 in the juices of plants, and the other is its action on dextrine, 



