248 J. C. Marquart's Report of the Progress of Phytochemistry 



even at 0°; it is even capable at —5—12° of rendering the 

 paste of starch liquid without at the same time forming sugar. 

 The conversion of starch into sugar takes place very rapidly, 

 as well in the air as in vacuo, and without the absorption or 

 disengagement of gas. 



M. Guerin examined the starch under the microscope, and 

 appears, as is often the case with the French, to have had no 

 knowledge of the experiments made by the Germans on the 

 same subject. He observed, like M. Fritsche, the concentric 

 rings and the nucleus of the granules, and very improperly 

 names the latter the umbilical point ; he also found the mon- 

 Straus grannies of M. Fritsche, and describes them as a con- 

 nection of one or two granules which, on account of want of 

 space in the mother cell, had forced themselves on one another 

 so that the formation of hexagonal cells by the aggregation 

 of the original round cells could plainly be observed. The 

 umbilical point of each granule was always directed outwards. 

 M. Guerin, after having in this manner studied the form of the 

 granules, made experiments on the action of water on them at 

 various temperatures, sometimes using pure water, sometimes 

 water and diastase; from which it appears in general, that at 

 50 — 53° C. the water with or without diastase had no effect 

 on the granules; at 54' — S5^ he perceived some torn granules, 

 and at 59 — 60° several granules quite torn, and many already 

 empty; at 62° all the granules torn and enipty, yet so, that in 

 diastase the husks were only split, but in water broken down 

 into shreds, [gefranzt). 



Of more importance are the remarks of M. Hartig on the 

 appearance and function of starch in the vegetable kingdom, 

 in his memoir '^ On Starch, Cambium, the nutritive sap and 

 milk-sap of woody plants, in reference to phytochemistry, che- 

 mistry, and common use*." M. Hartig found in the woody 

 body of all deciduous trees after the fall of the leaves a great 

 quantity of starch (up to 26 per cent.), which in spring, as soon 

 as the sap begins to ascend, gradually diminishes from the pe- 

 riphery to the centre, being dissolved by the carbonated water 

 ot the ascending stem. With this solution there appears to 

 be connected an action on starch similar to the known action 

 of the weak mineral acids in the first moments ; namely, the 

 reaction of iodine has ceased and gum is formed, the solution 

 of which forces its way through the medullary rays to the bark 

 and here forms the basis of the young wood. For according 

 to the author, Cambium is the young cellular tissue, over- 

 charged with sap, forming activejuices (Bildungssafte), and not 



♦ Scluvcigger and ErUinann, Journ.filr jiraUuchc Clicmie, vol. v. part iv. 



