SCIENTIFIC NEWS. 



[Mar. 3, 1 8 



DR. DALLINGER ON THE DECOM- 

 POSITION OF ORGANIC MATTER. 



AT the conclusion of the fourth year of his presidency 

 of the Royal Microscopical Society, Dr. Dallinger 

 delivered to the assembled Fellows of the Society a very 

 interesting address, summarising the results of his own re- 

 searches in a very important department of micro-biology. 



Time was, and that not long ago, when it was believed 

 by men of learning that the dead animal, or plant, reverted 

 spontaneously to its elements, or at least to exceedingly 

 simple compounds. Time was also when such processes 

 as decay or putrefaction were considered of little import- 

 ance to man or to the world at large. All this has now 

 been changed. Thanks to the labours of Pasteur and 

 others, we now know that, but for the labours of certain 

 almost invisible beings, the lifeless remains of plants and 

 animals would encumber the earth for an indefinite time, 

 and that grand cycle of changes by which death is made 

 thebasisofnewlifecould notoccur. The destructive process 

 which we call putrefaction, and for which some of us profess 

 a lofty disdain, is simply a kind of fermentation. Just as 

 a yeast-cell sets up the alcoholic fermentation in a solu- 

 tion of sugar, splitting up the sugar into carbonic acid and 

 alcohol, so a putrefaction-cell sets up a series of changes 

 in a solution of defunct organic matter. If we take meat 

 broth, or albumen, or milk, or, instead, a decoction of 

 wheat-grains, or of peas/ or tea- leaves, and "sterilise" it 

 by a sufficiently prolonged heat, and then keep it in air 

 which has been perfectly freed from " germs," it will 

 keep for any length of time without change. But if we 

 introduce the smallest particle of matter which is already 

 putrefying, or if we even admit the ordinary air, which 

 is always rich in germs, decomposition at once sets in. 

 All this has been known for some time, but Dr. Dal- 

 linger has thrown a new and most instructive light upon 

 the whole process. It has been generally supposed that 

 this change was effected solely by one or two species 

 of bacteria. No doubt the first attack in such cases is 

 ordinarily made by Bacterium termo. We never find a 

 decomposing solution of albuminous matter in which 

 this form is not abundant. But if we cause large masses 

 of animal or vegetable matter to lie in water at ordinary 

 temperatures, and carefully follow, as Dr. Dallinger has 

 done, the course of decomposition, we see that the process 

 is effected not by one single organism, but by many, which 

 succeed each other in a regular manner. Each set in 

 turn makes its appearance at some fixed stage, takes up 

 the work, feeds and multiplies, and in so doing prepares 

 conditions suitable for its immediate successor. 



Beginning with Bacterium termo, this minute plant 

 makes its appearance in the fluid surrounding a mass of 

 decaying fish or flesh, and multiplies at a wonderful rate. 

 It seems to cover the putrid matter with a kind of film, 

 whilst offensive and noxious gases and vapours are being 

 thrown off. In the course of a week or more, according 

 to the weather, certain spiral forms appear, which are 

 constantly in motion. They invest the putrefying tissues, 

 and render them soft and pulpy. Then come a series of 

 monads, which Dr. Dallinger has more particularly 

 studied. Yet the exact parts which they take in the 

 process, and the nature of the changes which each form 

 brings about, will require much further examination. 



These, again, are succeeded by other organisms, which 

 at first swim and revolve, and glide about among the 

 putrid matter. 



One of these beings, known as Heteromita rostrata, is 



provided with a so-called " flagellum," a miniature whip- 

 lash, which trails gracefully after it as it swims. This 

 creature, at certain stages of its life, anchors in innumer- 

 able swarms — it is no exaggeration to say billions • by 

 coiling the fibre it brings the body down to the point of 

 anchorage. Then suddenly shooting it out, with a speed 

 which the eye can scarcely follow, it. brings it down like 

 a hammer upon some point of the decaying mass. After 

 resting for a second or two it repeats the operation. 

 These tiny blows being thus constantly delivered over 

 every part of the tissue gradually break it up, and caus^ 

 it to disappear. Nor is Heteromita rostrata the only toiler 

 thus employed. Other forms, some of them still 

 more powerful, are at work. Thus after the lapse 

 of from one month to three the entire mass of organic 

 matter has disappeared as such. There remains merely 

 in the glass or the pond, water of a pale grey colour and 

 of noxious properties, charged with carbonic acid and 

 carburetted hydrogen, whilst a fine, impalpable sediment 

 of a buff colour is left at the bottom. What point 

 of the process is most fraught with danger is by no 

 means certain — not necessarily that at which the vapours 

 given off are most offensive to human senses. 



Dr. Dalhnger is thus led to conclude that the most 

 important of all ferments, that by which all dead organic 

 masses are removed, is exceedingly complex, and includes 

 the successive living action of a series of organisms • 

 specially adapted to this task, and for ever at work all 

 the world over. 



It is scarcely needful to say that this subject, here 

 imperfectly sketched, has doubtless very important 

 sanitary bearings. 



Dr. Dallinger concluded his address by showing that 

 the vital processes of the very simplest and lowest life- 

 forms are as much guided and governed by immutable 

 laws as the most complex and elevated. " The irre- 

 fragable philosophy of modern biology is that the most 

 complex forms of living creatures have derived their 

 complexity from slow and progressive variations and 

 survival from the simplest forms. If, then, these simplest 

 forms of the present and the past were not actuated by 

 the same accurate laws of life, how did the rigid certain- 

 ties that govern the more complex come into play ? " 



No fact really supports the supposed abrupt trans- 

 formation of one kind of animal or plant into another, and 

 there is no room in philosophy for such a supposition. 



■'-^5^i;^>>^5<f-t 



COLOUR BLINDNESS A BRAIN 

 AFFECTION. 



PROFESSOR RAMSAY believes that the particular 

 defect giving rise to colour blindness lies, not in 

 the eye itself, but in the brain. Certain persons, he 

 points out, are incapable of judging which of two 

 musical tones is the higher, even when they are more 

 than an octave apart. Yet, as such persons hear either 

 tone perfectly, the defect is not one of deafness. He 

 accordingly argues that in such persons the brain is at 

 fault, and thence proceeds to the assumption that it may 

 be equally true that the inability to perceive certain 

 colours is not due to a defect in the instrument of sight, 

 the eye, but to the power of interpreting the impressions 

 conveyed to the brain by the optic nerve. If this is the 

 case, the problem is no longer a physical one. It falls 

 among those with which the mental physiologist has to 

 deal. — The Medical Press. 



