ABSTRACTS.

The cause of these failures was explained by Wassermann and Ostertag. They showed that a serum obtained by the use of one variety did not exhibit sufficient protective power against all other varieties of the same species, but only against the variety which had been used to immunise the animal yielding the serum. The virulence of the variety employed is not of primary import­ance, for serum prepared from a very virulent variety showed no protective action against Varieties of very much less virulence. According to Wasser­mann and Ostertag, the explanation of this peculiarity was to be sought in ultimate biological differences between the different organisms of swine plague, and particularly in the fact that the bacterial protoplasm did not ,consist of a single substance but was built up of different components. In the different varieties these components might vary considerably, and thus cause important differences, inasmuch as each component produced special peculiarities in the protective serum obtained by its injection.

Bruck studied the principle of polyvalence more thoroughly by experimental methods.

As a result of parallel tests of the before mentioned "septicidin" and Hochst swine plague sera, Bruck proved that these sera did not confer protection against al~ varieties, however virulent the variety employed in preparing them, but only gave protection against some, whilst the polyvalent swine plague seru.m prepared by Wilhelm Gans (Frankfurt) protected against all varieties alike, even when the dose of bacilli administered was greatly in excess of the (usually) fatal quantity.

Bruck came to the following conclusions :-(1) The virulence of the swine plague organism undergoes great changes by artificial cultivation. (2) The swine plague organism forms no toxin soluble in water. (3) The bacillus suisepticus does not form any considerable amount of haemolysin or leucocidin (substances causing disintegration of red and white blood cor­puscles). (4) In practice polyvalent sera are greatly to be preferred for conferring protection against swine plague. (5) Polyvalent is distinguished from monovalent serum by the fact that in consequence of its greater richness in varying secondary products a somewhat higher concentration is required, but it affords protection over more widely seplrated districts.

The value of the principle of polyvalence as applied to the preparation of swine plague serum must, in view of the success obtained, be regarded as fully demonstrated, tor when a monovalent serum is employed against a variety of bacillus to whose secondary peculiarities it is unfitted it must fail, whilst the chances of success in using a polyvalent serum are, as above demonstrated, much greater. (Bruck, Zeitschr. f. .Hjg. und Illfektiollsk, Vol. XL VII., Part 3, and Osterr. Mona/s. fro Tt"erhlk.)

EXPERIMENTS WITH SEPTICIDIN IN THE TREATMENT OF SWINE PLAGUE.

BREIDERT tested the activity of the septicidin prepared at Landsberg. As sent out, it is stated to give protection against swine fever, swine plague, fowl cholera, and pneumonia of calves (chronic form of "white scour "). He used ten varieties of swine plague bacteria, a fatal dose of which was rendered harmless by injecting ·01 gramme of Wassermann and Ostertag's polyvalent serum. Septicidin only afforded protection against one of these varieties. The general conclusion was that septicidin gave no protection against eight selected varieties of swine plague organism, whilst Wassermann and Ost('rtag's polyvalent serum protected against all of them.

ABSTRACTS.

Breidert also tested septicidin against swine fever and fowl cholera, and found, contrary to the claims made for it, that it conferred no immunity . .(Breidert, Zeitschr. f. Hyg. ltnd Infektionsk, Vol. XLVII., Part 3, and Osterr. Mona/s. Jr. Tierhlk.)

DISEASES PRODUCED BY TRYPANOSOMATA.

Professor Koch recently delivered an address, of which the following is the ,substance, to the Berlin Medical Society regarding his experiences and obser­vations on diseases produced by trypanosomata in Africa :-

A wide field of study has recently been opened by the discovery of various pathological protozoa. Three discoveries especially have directed attention to these special disease organisms-

r. Laveran's discoveries regarding malaria. Ross has shown that the malaria parasites are carried by mosquitoes (anopholes).

2. The discovery of the protozoa of Texas fever by Smith. In this case ticks (ixodes bovis) convey the disease,

3. The discovery of the trypanosoma Gf the tsetse disease, which is con­veyed by a Slinging fly (glossina morsitans).

These discoverIes were followed by numerous others indicating protozoa as causes of disease.

The trypanosomata are morphologically distinguished by the existence of a flagellum. When fre,h blood is examined it is scarcely possible to overlook the protozoa in the preparation, for attention is at once attracted by the ener­getic way in which the red blood corpuscles are continually being displaced. The peculiar form of the protozoa, however, can only be detected in stained preparations. Romanowsky's staining method is probably the best. Trypano­somata stained by this method show a fish-shaped body, the front end of which carries a flagellum. The body of the trypanosoma is coloured blue. At the anterior end may be seen a red-stained nucleus; at the opposite end a much smaller red spot, which has been termed the nucleolus, but is more properly described as the centrosome. From the centrosome a red thread extends along the outer margin of the body as far as the front extremity, where it becomes continuous with the flagellum.

The trypanosomata increase by longitudinal fission. The centrosome and then the nucleus divide, and finally a second flagellum is formed. Some­times the young trypanosomata remain connected, producing the so-called " rosettes."

The disturbance produced by trypanosomata seldom becomes acute .. but often continues for years. The only sign of disease consists in ill-defined fever with long Intermissions. The destruction of the red blood corpuscles causes an:emia, the animals or men become weak and waste away, <::edema and sometimes erythema occur at varying points in the body, and occasionally the lymphatic glands become swollen.

Trypanosomiasis of rats is one of the most frequent forms of the disease. About 30 per cent. of all rats harbour trypanosomata" and in some cases the percentage is as high as 90.

The trypanosomata of rats are morphologically distinguished by possessing a long point at the posterior end-i.e., the end opposite the flagellum. The centrosome lies rather far back.

It is peculiar that the trypanosomata of rats seem to produce no morbid symptoms, nor do they injure their hosts in the slightest degree. They can only live in the bodies of rats, and not in those of mice. Conveyance frum

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