Let the albumen fall on the center of the filtered liquid, avoiding, if possible, contact with the glass of the beaker. It soon sinks, and after the lapse of some time, a simple inspection will show which is dissolving with the greater rapidity. Agitation assists solution. Therefore take the two beakers, one in each hand, and rotate the contents equally. When one sample has dissolved all the albumen, it is manifestly superior to the other which has failed to do so in the given time. If many samples have to be compared, it will be necessary to start with known quantities of albumen, and weigh the undissolved residues in the manner above indicated.
An objection may possibly be raised to this modified method, viz., that albumen as ingested is not in the form of a dry powder, and that we ought to copy as nearly as possible the conditions existing in the stomach. To this I would reply that it does not matter in the least, to us, as analysts, what are the conditions which obtain in the stomach; since there is no absolute test for pepsin, we can only compare one sample against another, and that which dissolves the most albumen in the shortest time is taken to be the best.
Another imperfect method of analysis is that employed in the examination of malt extracts for diastase, in which a certain weight of extract ought to dissolve a certain weight of starch in ten minutes, when if it does so dissolve it, the extract is a good one; if not, it is to be condemned. The more correct way is to ascertain the reducing power on Fehling's solution, before and after digestion with an excess of starch, and I intend to say a few words upon this subject on a future occasion, when I have ascertained the maximum amount of diastase existing in the best samples of malt.—The Analyst.
SUBTERRANEOUS FLORA AND FAUNA.
By Dr. Otto Zacharias.
It is generally correct to say that air, light and moisture form the chief conditions necessary for the development of organic plant or animal life. One of these conditions, however, namely light, is not of equal importance with the two others. For modern investigation and the discoveries made during the progress of natural sciences have shown that in the depths of the ocean, where an everlasting darkness reigns, and where the temperature is extremely low, nevertheless a great abundance of animal life is to be found, and that there exist living beings, not only of the lowest organization, but even fishes and crustaceans of very complicated structure, all of which thrive without enjoying the slightest ray of light.
A similar example of animal life in the absence of light is to be found in the fauna of caves and grottoes. This was first made known to the world by Austrian and American naturalists. The well known Adelsberg grotto in Krain, and the gigantic Mammoth Cave in Kentucky, furnished much interesting material for a detailed study of the biological conditions of subterraneous animal life. It was gradually discovered that in those dark places there existed not only insects, spiders, crustaceans, centipedes, worms, and snails, but also a kind of salamander and fishes. But what gave special interest to these discoveries was the fact, ascertained by careful study, that not all of these beings were gifted with normally developed organs of vision, but that in some these organs had undergone a retrograde development, while others were entirely blind.
Fig. 1.—THE SEMI-BLIND SALAMANDER (PROTEUS ANGUINEUS) OF THE ADELSBERG GROTTO, IN AUSTRIA.