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 himself, remind us in many respects of von Mohl, though it would be more correct to say that von Mohl's manner reminds us of Moldenhawer, for from the great respect which von Mohl displays for him, especially in his earlier writings, it can scarcely be doubted that he formed himself on Moldenhawer's 'Beitrage,' and first learnt from them the earnestness and carefulness demanded by phytotomic work.

It has been already mentioned that the study of vegetable physiology is indebted to Moldenhawer for one important practical improvement. He was the first who isolated cells and vessels by allowing parts of plants to decay in water and afterwards crushing and dissecting them, a process not much used in modern times, though it may still be applied with advantage in conjunction with what is known as Schulze's solution, especially if it is carried out with Moldenhawer's carefulness and circumspection. The isolation of the elementary organs of plants by maceration in water necessarily brought Moldenhawer into direct antagonism with Mirbel, who with Wolff assumed that the partition between any two cells was a single wall; whereas Moldenhawer found that the cells and vessels were closed tubes and sacs after isolation, and must necessarily, as it would seem, so lie one against another in the living plant, that the wall between every two cell-spaces is formed of two membranous laminae, and he expressly says that this is the case even in very thin-walled parenchyma. This result remained unassailable, so long as no one was in a position to conclude from the history of the development of cell-tissue that the partitions are originally single, or by aid of strong magnifying power to prove the true structure of the walls and their later separation, and the differentiation of the once single wall into two separable laminae. If the view based on the results of maceration was still not the true view, yet it was nearer the truth as regards the matured state of the cell-wall than that of Wolff and Mirbel, and the important advantage was gained of being able to study the