The micrococci are best detected by placing the cover-glass with the dried-up fluid, coloured by aniline-water and gentian-violet solution, in a watch-glass with alcohol for half a minute, when the matrix rapidly loses its colour, the envelopes and micrococci much more slowly. The preparation may then be placed in a watch-glass with distilled water, examined in water, and afterwards preserved in Canada balsam or dammar lac. The envelopes are also coloured by eosin, especially by a weak solution acting for twenty-four hours; osmic acid differentiates them sharply, but without blackening them. These envelopes appear to be a highly characteristic peculiarity of the micrococci of pneumonia, never failing in acute genuine cases. They probably belong to the acme of that disease, not being found after the sixth day.

If developed by Koch's process on serum of blood and afterwards on gelatine, with addition of infusion of flesh, peptone, and sodium chloride, the micrococci have on serum of blood the form of a greyish pellicle on the surface, and an opaque cylinder in the interior of the serum. The cultures on gelatine were especially characteristic, and were propagated for eight generations. They resembled a nail with hemispherical head, and consisted of densely crowded micrococci, usually of elliptical form, but with no envelope. They were also cultivated on potato.

Experiments were also made in inoculating the pneumonia-micrococci in animals, by injection into the right lung. With rabbits no success was obtained; while mice always died in from 18 to 28 hours. In the cavities of the pleura, partly in the fluid, partly in the lymphoid cells, were masses of micrococci, with all the characters of those of pneumonia, including the envelope. They were also found in the lungs and blood. With dogs and porpoises no result was obtained in some cases, while others were successful. Experiments were also made with mice by inhaling; when some only were infected.

The size of the micrococci and development of the envelopes differ considerably with men and other animals. Those of mice were, on the average, larger than those of man; those of porpoises were smaller, but with broader envelopes; those of dogs were scarcely larger than those of man, and the envelope comparatively narrow. The mode of preparation also has an influence on the size of the micrococci.

Bacteria of the Cattle Distemper.*-The bacterium of the cattledistemper has been hitherto known almost exclusively in the bacillus condition, not making its appearance in the blood till some ten hours before the death of the animal. F. Roloff has examined the blood in the early stages of the disease, and also those organs, especially the spleen and the lymphatic glands, in which the bacilli are first seen. In all these he found a large number of small round shining bodies or micrococci. The infection of other animals with blood containing these cocci, produced in them the ordinary distemper with its bacilli, showing that the two are stages of development of the same organism.

* Arch. Wiss. u. Prakt, Thierheilkunde, ix. (1883). See Bot. Centralbl., xvii. (1884) p. 112.

Passage of Charbon-bacteria into the milk of animals infected with Charbon.*-Chambrelent and A. Moussons have made the following experiments to determine whether the milk of a female in lactation affected with charbon contains the microbium of the infection. A cobaye, which had up to that time suckled its young, was inoculated with the charbon-virus. It died the next day, and a drop of blood taken from the ventricles of the heart was found to contain an immense quantity of bacteria. A drop of milk was taken from the mamillary gland by means of a sterilized tube, and placed in a Pasteur's "ballon" containing infusion of beef. At this time the milk presented a perfectly normal appearance, and showed no evidence of bacteria, although there were abundance in the blood. Four "ballons" treated in this way were left in the stove for two days; two were then quite limpid, one appeared to contain impurities; the fourth presented some flocci, and gave the appearance of a charbonized culture. It contained bacteria and interwoven filaments, but only in small numbers. A young cobaye was inoculated with this culture by means of a sterilized tube. It died in two days and its blood was found to contain bacteria. The rest of the culture, left in the stove, had in four days more assumed completely the characteristic appearance of charbon-cultures. A cobaye inoculated with it died the next day.

In a second experiment the milk was removed before the death of the animal. A young cobaye in lactation was inoculated with charbonvirus; the next day it was still alive. Milk was removed from it in the same way as before; four Pasteur's "ballons" were inoculated with it and placed in a stove. After four days one remained quite limpid; two had assumed the characteristic appearance of charbon-cultures; the fourth appeared to contain some foreign ferment. The two charbonized cultures contained great quantities of the characteristic filaments. Two cobayes inoculated with the fluid died the next day, presenting the characteristic lesions of charbon.

In a third experiment a large rabbit in lactation was inoculated with the same virus, which did not kill it. The milk of this rabbit displayed no bacteria, and the blood only a very few. Inoculation with the milk produced no signs of charbon-bacteria, and only one out of two with the blood.

The experiments show conclusively that bacteria are found in the milk of animals infected with charbon while they are still alive; but their number is enormously smaller than in the blood.

Comparative Poisonous Action of Metals on Bacteria.t-C. Richet has experimented on this subject, and gives a table of his results. The liquid was sea-water, neutralized urine, and commercial peptone, and the particular metal was added in gradually increasing quantity, in the form of chloride, until no bacteria were developed after forty-eight hours at 16°-20° C.

*Comptes Rendus, xcvii. (1883) pp. 1142-5.

↑ Ibid., pp. 1004-6. See Journ. Chem. Soc.-Abstr., xlvi. (1884) pp. 351–2.

The amount of each metal which will kill fish is always much less than that required to prevent the development of bacteria. The marked poisonous action of ammonium, lithium, and potassium on fish and all animals is in striking contrast to the slight effect which these metals exert on plants and bacteria. Poisons may be divided into two classes, viz. general poisons, of which mercury is the most potent, which even in small quantities have a deleterious action on both plants and animals; and special poisons, such as potassium and ammonium salts, and the alkaloids, which are injurious only to animals, and exert little or no poisonous action on plants. The difference is probably due to the fact that poisons of the second class act only on nerve-cells, whereas those of the first class act on all cells. Possibly the action of ammonium and potassium salts may serve to distinguish between plants and animals in the lower forms of life.

Micro-organisms in Soils.*-From examinations of a large number of samples, R. Koch found that the superficial layers of soil were very rich in germs of bacteria, particularly in bacilli. Micrococci were only found in places which had not been cleansed from decaying matter; the latter perished on heating the samples, but the bacilli did not, being mostly in the condition of spores, and it appears probable that they are introduced by means of manures and household offal.

The quantity of micro-organisms diminishes very rapidly with increase of depth, so that at the distance of one metre from the surface the earth is very free from them. P. Miquel attempts to estimate the number present in one gr. of soil, taken from a depth of 0.20 metre from the surface, and found in three samples: from Montsouris, 700,000 organisms; Gennevilliers, manured with liquid sewage, 870,000; Gennevilliers not so treated, 900,000.

The office of these minute organisms appears to be of great importance in the transformation of substances to forms suitable for plant-food.

Bacteria and Microscopical Algae on the Surface of Coins in Currency.-Prof. P. F. Reinsch writes us as follows:-" Accidentally induced to examine microscopically the surface of a small silver coin, I made the observation of the presence of numerous Bacteria and microscopic unicellular algæ living in the incrustations and sediments which have been produced through constant use. I examined coins of various nations and of various value, and found my first observation perfectly confirmed. All silver and copper coins, several years in currency, show this curious vegetation of organisms of the lowest rank. It is observed best on coins twenty to thirty years old.

To observe this life, a small quantity of the sediment adhering to the prominences and in the cavities of the surface of the coin is scratched off with the top of a knife and put in a drop of distilled water on a slide, spread out in the water and immediately covered with a cover-glass.

Between the agglomerations of larger and smaller granules, scarcely dispersed fragments of fibres, and especially numerous granules of starch Bied. Centr., 1883, pp. 581-2. Cf. Journ. Chem. Soc.-Abstr., xlvi. (1884)

p. 486.

(in the most cases granules of wheat), are observed. In a short time numerous mobile minute bodies are seen, the mobility of which seems at first to be the well-known molecular motion, but is soon turned into the most active bacteroid motion. By using a higher power (500 diam.) we observe in the agglomeration various forms of bacteroid life, very well recognizable both by their constant relations of size and shape, and by the mode of motion peculiar to the various bacteroid types. There are rod-shaped Bacteria with oscillating and spiral motion, and globular bacteria with the peculiar rocking-oscillating motion. Sometimes all these forms of bacteroid life are found on one and the same coin; in most cases there are found on one coin more especially globular Bacteria, on another coin more rod-shaped Bacteria. The globular forms make up in the case of all coins the principal constituent of bacteroid life in the incrustation. Spirillum is not found very often, but by searching after it, and dispersing the substance under the cover-glass it is sure to be found in a great many cases. Bacillus, four to six divided rods of 0·0055-0·0074 mm. in length are found on all silver, copper, and bronze coins. The automobile motion of the bacteroid bodies, lasting for many hours, is instantly stopped with one drop of a solution of iodine or of concentrated glycerine placed on the margin of the cover.

Of

Of the unicellular algæ in the incrustations of nearly all the coins hitherto examined, I have distinguished till now two very distinct and constant types, the characteristics of which are so clear and constant, that they can be identified with known types of algae and classified in the system of algae. There is one most minute Chroococcus and one unicellular alga which I think very nearly allied to the Palmellaceæ. The slightly tinctured cells of this Chroococcus of 0.00925 mm. diam., form minute globular bodies, composed of 4, 8, to 12 cellules. These globular bodies are clustered together, forming minute irregular masses, 0.02 mm. diam. The Palmellaceous alga has many times larger, thick-walled cells; the contents of which are mostly intensely tinctured. The cells are found in all states of division from two to more. Of the Palmellacea Pleurococcus is the type, coming the nearest to this new alga. The cells in the undivided state are found 0.009-0.01 mm. diam. The thickness of the wall of the cells is equal nearly to 1/10 the transverse diameter of the cells. The cells in their many-divided state do not exhibit the same regular and symmetrical disposition of the daughter-cells as the typical Pleurococcus (P. vulgaris).

In addition to these organisms there are found in the incrustations of the coins (besides undeveloped fungoid hyphæ), spores of various Cryptogams of various size and shape, belonging to the Hyphomycetes and the Coniomycetes.

It may be concluded from the constancy of the characteristics and of the occurrence of these two unicellular organisms, that their occurrence is a spontaneous one, just as is the case with a large number of these organisms of the lowest state, concerning both living and dead matter; in other words that these organisms have to be considered not as accidentally adherent substances but as organisms,

which have their continual origin and seat in the incrustations of coins in currency. The discovery of the presence of these organic bodies (which, according to modern experiences, are generally recognized as important factors in the spread of epidemics) on objects so dispersed as coins, adds a new consideration in hygienic science. It seems also very probable that to the vital activity of these unicellular organisms, a share is due of the erosive process, perpetually going on on the surface of coins in currency.

The means for obviating the obnoxious influence of the organisms would simply consist in boiling the coins after a series of years of circulation, in a solution of caustic potash, and then cleaning the surface thoroughly from the incrustation."

The following is a description of the two new species:

Chroococcus monetarum. Cells minute, subglobose, angular, from 4 to 8 cells enveloped in a common mucilage and associated in small subglobose families. Diam. of cells 0.925 μ; diam. of families 0.460.56 μ.

Pleurococcus monetarum. Cells globose, with thick membrane, subtorulose (elevations 1/10 diam. of cell), undivided; from 2 to 8 cells associated in globose families; cell-contents brightly coloured. Diam. of cells 0.0074-0·011 mm.; diam. of families 0·011-0·0129 mm.

Rabies.-L. Pasteur, with the assistance of MM. Chambrelent and Roux, has another communication on rabies. Inoculation has been effected either by applying the poison of rabies direct to the surface of the brain, or by injection into the blood. The former would appear to be a long and difficult operation, but we are assured that it may be well completed in twenty minutes, starting from the moment in which the animal was being subjected to chloroform.

Pasteur has already shown that the inoculation of the virus into the blood is most often accompanied by paralytic seizures without fury or barking, and that the first part to be affected is the spinal cord; and he has also already proved that the poison is to be found in the brain and spinal cord. He has since experimented with nerves and salivary glands, and he has been able to get poison effects with portions of the pneumogastric and sciatic nerves, as well as with the maxillary, parotid, and sublingual glands. It follows then that the whole of the nervous system is able to cultivate the rabic poison, and we find in this fact an explanation of the high degree of nervous excitement which is so often a characteristic of rabies. Poison placed in carefully sealed tubes is virulent after three weeks or a month, even when exposed to a summer temperature. The fluid of the central nervous system is sometimes, though not constantly poisonous: when limpid it is so, but not when distinctly opalescent. Cultivation experiments of the virus have not as yet been successful, but Pasteur is always able to distinguish the brain of a healthy from that of a rabid animal. Both, under the Microscope, exhibit an immense number of molecular granulations, but in the rabid brain they are finer and more numerous.

* Flora, lxvii. (1884) pp. 173–6.

+ Comptes Rendus, xcviii. (1884) pp. 457–63.