Bineau on the Absorption of Ammonia by Cryptogamic Plants. 375 



M. Bineau has made some observations on the absorption of 

 ammonia and the nitrates by cryptogamic plants. His experi- 

 ments were made on the HydrodictyoH pentagonale and the Con- 

 ferva vulgaris. He infers from them these consequences : — 1. The 

 demonstration of the fact of an absorption or of a decomposition 

 of ammoniacal salts with an intensity analogous to that of CO^. 

 This has hitherto had no parallel in the case of saline matters, 

 which are generally absorbed much less abundantly than their 

 solvents. 2. That the nutrition of the Algse is promoted by their 

 tendency to remove the nitrates from the waters in which they 

 vegetate, either by directly assimilating the nitrogen, or by con- 

 verting the nitrates into ammoniacal salts. 3. That the elabo- 

 ration by green plants of nitrogen compounds, as well as of car- 

 bonic acid, is facilitated by light. 



In the November Number of Liebig's Annalen, Dr.Casselmann 

 discusses at some length the process proposed by Streng for volu- 

 metric determinations by means of bichromate of potash. He 

 communicates the results of some comparative experiments which 

 he made with a view of testing this method, and describes the 

 conditions under which it is applicable. He considers that the 

 method has only a limited application for scientific purposes. 



M. Toel describes the formation of cystine in the urine of 

 two females who suffered under an inflammation of the kidneys. 



The late Dr. Pauli discovered in wood-vinegar an acid which 

 he thought to be pyrogallic acid ; since his death the question 

 has been examined by M. Buchner, who finds that it is not py- 

 rogallic acid, but oxyphenic acid, C'^H^O'*. This acid invari- 

 ably accompanies the products of the destructive distillation of 

 wood, but is not found in coal-tar, being probably decomposed 

 by the presence of ammonia. 



M. Kerl proposed a method for the determination of copper, 

 which consisted in precipitating it from its solution by means of 

 metallic iron. The metallic copper which precipitates is then 

 dried and weighed. M. Mohr proposes to substitute zinc for 

 iron in this process, and gives the analytical results of determi- 

 nations made in this way, which were very accurate. The copper 

 salt or mineral is dissolved in hydrochloric acid. H' nitric acid 

 be present, it must be removed, either by lengthened boiling of 

 the strong hydrochloric solution, or by adding a little sulphate 

 of iron. Distilled zinc is then added. When the copper is en- 

 tirely precipitated, which is ascertained by testing a drop of the 

 solution with sulphuretted hydrogen, and the whole of the zinc 

 dissolved, the copper is washed, dried, and weighed in a crucible. 



