. Experimental morphology. Protoplasm; Growth. § 1] UPON THE RATE OF GROWTH 319 the second culture, on the other hand, little growth had occurred even at the end of five weeks. The crop from each of the cultures was then harvested and its dry weight determined. That of the first culture was gramme, that of the second gramme. By a somewhat similar procedure MOLISCH ('95) has been able to show that potassium is essential to the growth of algse ; and NoBBB and others ('71) that it is necessary for the growth of phanerogams. The experiments upon animals have been rather less satisfac- tor
. Experimental morphology. Protoplasm; Growth. § 1] UPON THE RATE OF GROWTH 319 the second culture, on the other hand, little growth had occurred even at the end of five weeks. The crop from each of the cultures was then harvested and its dry weight determined. That of the first culture was gramme, that of the second gramme. By a somewhat similar procedure MOLISCH ('95) has been able to show that potassium is essential to the growth of algse ; and NoBBB and others ('71) that it is necessary for the growth of phanerogams. The experiments upon animals have been rather less satisfac- tory on account of the greater difficulties in Fig. 88. —Two embryos ol Sphaerechinus from parallel cultures. <x, reared in a solu- tion containing all the necessary salts; embryo normal, b, reared in the same solution, but without potassium; blastula wall abnormally dense, and embryo of small size. (From Herbst, '97.) Nevertheless we have some trustworthy data upon this matter. On the side of the invertebrates we have the experiments of LoEB ('92), who placed a hydroid, Tubularia, in fresh water to which solutions of various combinations of the salts found in sea water were added so as to give approximately the nor- mal osmotic effect. Under these circumstances regeneration of the hydroids occurred only in the solutions containing potassium. Again, Heebst ('97) finds potassium essential to the growth of embryos of echinoids (Fig. 88). Thus the potassium compounds seem necessary to the processes upon which growth depends. On the side of vertebrates we have the somewhat inconclusive results of Kemmerich ('69), who fed two young dogs of the same age and of nearly the same size upon meat boiled until a large portion of its salts was extracted. To the food of one dog he added only sodium chlo-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrat
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