116 PROCEEDINGS OF THE ACADEMY OP [1884. 



circumstances the presence of peptone in amounts of less than 

 one part in five thousand is readily shown. By the exercise of 

 great care in the performance of this test he had been enabled to 

 demonstrate the ])resi-nce of peptone in a solution containing 

 but one part of that body in seventeen thousand parts of water. 



The condititjus interfering with this reaction are : alkalinity of 

 the fluid examined (readily overcome. by neutralization); heat, 

 "which has the same influence upon the nascent mercuric iodide as 

 have peptone and the bile-salts ; and the presence of certain com- 

 pounds, as potassium ferrocj'anide, which chemically prevent the 

 production of the mercuric iodide. 



The reaction just described presents certain advantage from the 

 fact that it is uninfluenced by the bodies usuall}^ found in the 

 various organic fluids. It is efficient in the presence of a twenty 

 percent, solution of serum ; the presence of considerable amounts 

 of coagulated albumen and of acid-albumen does not interfere with 

 the test. The following bodies in moderate amount do not affect 

 the reaction : Saliva, S^'utonin, Am3^gdalin, Para-Albumen, Dias- 

 tase, Kreatin, Leucin, Pyrosin, Mucic Acid, Glucose, Urea, Uric 

 Acid, Nitric, Hydrochloric, Sulphuric and Picric Acids, Gl3'c- 

 erine, Alcohol, Atropia Sulphate, Pilocarpin Nitrate, Caff'eine, 

 Sodium Carbonate, Ammonium Oxalate, Sodium Phosphate, and 

 Manganese Chloride and Ferric Chloride. 



It is obvious that this reaction is useless to the student as an 

 isolated test, inasmuch as it responds to two entirely distinct 

 compounds, but its simplicity and striking colorations give it 

 very considerable value when employed in cori'oboration of other 

 tests. 



Botanical Notes. — At the meeting of the Botanical Section on 

 April 14, Mr. Thomas Meehan made some observations on the 

 following topics : — 



Evolution of Heat in Plants. — Referring to some observations 

 of Kerner respecting the thawing out of chambers in ice by living 

 plants in the Alps of Europe, he confirmed them by observations 

 on Erartthis hyemalis made during the past, winter. At the end 

 of January the plant was in flower after a few warm days, when a 

 driving snow-storm prostrated the little stems, and covered them 

 nearly a foot deep, in which condition they remained till earl}' in 

 March. After they had been three weeks in this condition, the 

 snow was carefully removed, when it was found that the stems 

 had become perfectly erect, and a little chamber in the snow had 

 been thawed out about each flower-stem. There was, however, no 

 other evidence of growth. The few buds which were unopened 

 when the snow came, were still unopened when the snow thawed 

 away, after five weeks' imprisonment; and the idea conveyed was 

 that plants would retain life, without growth, for an indefinite time, 

 when under a low temperature, such as a covering of ice or snow 

 afforded. 



