904 PKOOEEDINGS OF THE SOCIETY. 



into the passive condition, loses the aldehydic groups by displacement 

 of the atoms (' Atomumlegerung ') and the intense chemical motion 

 has ceased herewith at once." 



Mr. Stewart said that the remarks which he made on the occasion 

 referred to were hardly offered as a matter of criticism, but rather by 

 way of inquiry. It was clear that the experiments of the authors had 

 been conducted with singular precision, and he was very glad that his 

 observations had been the means of bringing out these additional 

 particulars. He might also say that the original paper of Drs. Loew 

 and Bokorny having been sent to him, he had laid it before Dr. 

 Bernays, the chemical lecturer at St. Thomas's Hospital, who had been 

 so much interested in the subject that he intended to thoroughly 

 investigate it, and no doubt they would in due course hear the results 

 of his experiments. Meanwhile, as a preliminary, he had received 

 from him the following letter : — 



" I have read the letter of Drs. Loew and Bokorny, and consider 

 as proved by them that the power of producing alkaline silver solu- 

 tions is an essential property of many forms of living vegetable 

 plasma. I consider that a complete answer is furnished to your own 

 suggestion about residual citric acid : that must be given up. The 

 experiments of Drs. Loew and Bokorny have been made with a care 

 and skill deserving of the highest praise. 



Of the nature of animal protoplasm little is known. The authors 

 of ' Die Chemische Kraftquelle im lebenden Protoplasma ' admit as 

 much; but they consider themselves entitled to the judgment that 

 the reactions of aldehyde groups in active albumen are capable of 

 equal application. The cases of chronic silver-poisoning do not seem 

 to confirm the view, as we should certainly expect on the aldehydic 

 theory a much more even distribution of metallic silver. And, in the 

 case of man, alcoholic potations would have to be rigidly excluded in 

 order to assist in the confirmation, or otherwise, of the aldehydic 

 theory. Whether any, and what, differences exist between vegetal 

 and animal albumens we cannot exactly say. 



The aldehydic theory is the most interesting attempt at explaining 

 the distinction between living and dead protoplasm that has ever been 

 offered. But, although the reactions discovered by Drs. Loew and 

 Bokorny are similar, in the one aspect of reducing alkaline silver 

 solutions, I do not see more in their most interesting statements of 

 experiments and views than to confirm most successfully the differ- 

 ence between living and dead plasma. For myself, I say, with all 

 deference to these distinguished scientists, that further proof must 

 be offered of the view these gentlemen hold, before I would accept 

 the aldehydic theory as more than an interesting attempt at explana- 

 tion." 



Mr. Crisp read a note from Mr. C. Stodder as to the Tolles ^-inch 

 objective with tapering front, exhibited at the June meeting (see 

 p. 589), in which the writer pointed out that the speakers at that 

 meeting, who stated that " similarly tapered " objectives had been 

 made as early as 1848 by Andrew Boss, and since by others, had not 

 understood " the peculiarity or the purpose of the construction of the 



