ally increasing doses, into large animals suitable for the purpose, e.g., the horse. In course of time the blood serum of the animal becomes strongly bactericidal and antitoxic, and by frequent bleeding a continual supply of the serum can be obtained. Standardisation of the serum is effected by injecting various doses of the serum into test animals, and following this with a virulent culture of the bacterium, or a lethal dose of the toxine in question. By noting the effect upon the test animals, the amount of serum necessary to immunise against the bacteria or toxine for a certain bodyweight is determined.

A Panacea for Bacterial Diseases.

As our knowledge increases the antitoxines and bactericidal sera will doubtless become simplified. Already Emmerich and Löw have prepared an enzyme from Bact. pyocyaneum, which destroys most of the species of pathogenic bacteria by dissolving their cell-walls or protecting capsules. By artificially forming a non-diffusible albuminoid compound with the enzyme, they claim to have been able to confer upon animals an immunity lasting several weeks, thus enabling them to withstand infection with different virulent bacteria. An antitoxic action is also claimed for this preparation.

Gamaleia had already shown that certain alkaloids, and especially the ammonia salts of glutamic acid, produce a destruction of the staining power of bacteria. If a solution in which this occurs is precipitated with acetic acid, the precipitate dissolved in ammonia, and added to cultures of pathogenic bacteria, there is obtained a bacteriolysin which dissolves bacteria. We thus see that a simplification of the bactericidal sera is claimed by these investigators, and it seems probable that we shall soon have a panacea for all the bacterial ills to which this flesh is heir.

In the following experiments, Potassium Cyanide, free from carbonate, and distilled water were used; the glass particles were also cleaned by treatment with acid, ammonia, distilled water. The method of experiment was as under:

An ordinary gauge glass tube was closed at one end with a piece of calico to form a filter; glass particles were filled in to form a column in the tube exactly 12 inches in height. The volume of the tube having been determined by weighing the amount of mercury required to fill it to the given height, and the specific gravity of the glass used being known, the volume of the void-space in the column of particles was obtained.

Particles of four degrees of fineness were experimented on. 1. The particles passed through a 40 mesh sieve, remained on a 60

In each case 25 cc. of solution, containing 2075gm. 25cc. KCN were allowed to percolate through the column; this was immediately followed by a water-wash of equal volume. The total volume of solution passing through was measured, and the amount of KCN and KCNO in it determined. The particles were then removed from the tube, digested with dilute HCl, washed, and the amount of K in the filtrate estimated with platinic chloride.

The cyanate formed was estimated by taking 10cc. of the solution, and adding AgNO,, until all the AgCN and AgCNO was precipitated. The washed precipitate was treated with 5cc. normal HNO and the acid remaining titrated with NaOH.

39

All experiments were made in duplicate. are given in the accompanying table:-

Size of Total

The results

KCN KCN ox- KCN re-KCN un- KCN Retained particles. KCN ori-after per-idised to tained on accountSieve. ginally colation. KCNO. particles. ed for.

to

on

KCNO. particles.

present.

In the two first instances the solutions percolated in under 20 minutes; in the case of No. 4, the time taken was 2 hours; and this variation in the time of percolation would corre spondingly affect the results, which are probably low as regards oxidation, in the case of No. 1 at any rate.

As an ordinary tailings heap contains a considerable percentage of particles which would pass through a 100-mesh sieve, and a small amount of very much finer material, the above results afford a partial explanation of the exceedingly rapid consumption which takes place when KCN solutions are run on to a dry ore.

As the cyanate formed during percolation must obtain the necessary O from the air in the void-spaces between the particles, the amount of O present is readily determined; and, assuming the O and N are in the ordinary proportions in the tube, the following results are obtained:

Wt. of O corresponding Vol. of O in to Cyanate cc. at NTP. formed.

Vol of total Vol. of total gases in tube. void in tube.

Degree of Compression

THE CHEMISTRY OF THE EUROPEAN, ASIAN, AND NEW ZEALAND SPECIES OF CORIARIA.

By Prof. EASTERFIELD, M.A., Ph.D., and B. C. ASTON.

[Abstract.]

1. Coriaria myrtifolia (Southern Europe) has been shown to contain ellagic, gallic, and tannic acids, a yellow glucoside, together with a highly toxic glucoside coriamyrtin (Reban, 1866).

2. The three New Zealand species of coriaria are considered the most poisonous plants in that Colony. They contain the same acids as the European species, and the same colouring matter, but the toxic principle is a new glucoside tutin, perfectly similar in pharmacological action, but slower in producing the physiological effects.

3. Only one species is recorded from Asia (C. nepalensis). This is not known to be poisonous, and the authors have not succeeded in isolating a toxic substance from it.

4. The examination is being extended to the Mexican species, with the object of furnishing material from the chemical standpoint for those engaged in the study of variation.

THE POISON OF THE KARAKA BERRY.

By Prof. EASTERFIELD, M.A., Ph.D., and B. C. ASTON. [Abstract]

THE karaka tree (Corynocarpus laevigata) is endemic to New Zealand and the surrounding islands; the kernel of the berry is a staple article of Maori food in the North Island. The berry is intensely poisonous in its raw state, but is rendered innocuous by cooking and subsequent soaking in

water.

Chemical examination has shown

1. That the air-dried powdered kernels contain 14 per cent. of a non-poisonous, easily saponifiable oil, together with mannite, mannose, and dextrose.

2. An aqueous extract of the kernel yields prussic acid on distillation, and at the same time loses its bitter taste.

3. After the bitter taste has disappeared, the solution contains a non-nitrogenous, non-toxic compound, easily soluble in ether, and which is not present in the freshly-prepared solution.

4. The freshly-prepared solution contains a nitrogenous, bitter glucoside (C15 H., N, O15 M.P.122), and sparingly soluble in cold water, alcohol, ether, &c., easily soluble in acetone and acetic ether. This glucoside is probably identical with that described by Skey under the name karakin, but as Skey's description appears to have been based upon an examination of impure material, the properties of the two substances do not agree closely.

A second glucoside corynocarpin has been isolated; it is probably a product of the limited hydrolysis of karakin.

NOTE ON EMPLOYMENT OF RAOULT'S METHOD FOR MOLECULAR WEIGHT DETERMINATION IN ELEMENTARY SCIENCE

CLASSES.

By Prof. EASTERFIELD, M.A., Ph.D., and JAMES BEE, M.A.

[Abstract]

THE cryoscopic method is one of the most rapid of the many methods for the approximate determination of molecular weight. The necessity for employing delicate thermometers has, however, been generally held as deterrent to the employment of the method amongst elementary students.

It is, however, evident that if, in applying the well-known formula,D K =

=

W x 100
Sx M

=

(in which D = observed depression; M = mol. weight sought; W = weight of dissolved solid; S weight of solvent; K a constant for the particular solvent), the depression might be measured on a common thermometer if a solvent were taken with a high depression constant and the dissolved substance were of sufficiently low molecular weight. Thus, the molecular weight of water is 18, the constant for phenol 720, so that 1 per cent. of water depresses the m.p. of phenol nearly 40, and since degrees on a common thermometer can easily be assessed to fifths, good values can be obtained with the simplest apparatus, viz., common thermometer, brass-wire stirrer, and test tube. is important in the case of water in phenol that the concentration shall not exceed 1.5 per cent, since at higher concentration molecular association takes place with extraordinary rapidity.

It