in the second case as tolerant,' for it tolerates the presence and multiplication of the parasite without suffering by it.

We have yet to learn a good deal more as to the repulsion and the toleration of the trypanosome parasites by mammals and man. Still more have we to learn about the life-history of the trypanosome. At the moment of writing, absolutely nothing has been ascertained as to the life-history of the trypanosomes of mammalian blood, except that they multiply in the blood by longitudinal fission. Our ignorance about them is all the more serious since other trypanosomes, discovered by Danilewsky in birds, have been studied and have been shown to go through the most varied phases of multiplication and change of size and shape, including a process of sexual fertilisation like that of the malaria parasite, to which, indeed, it now seems certain the trypanosomes are very closely allied.

It is to Dr Schaudinn, of Rovigno, that we owe a knowledge of some most extraordinary and important facts with regard to the trypanosomes parasitic in the blood of the little stone-owl of southern Europe (Athene noctua). These facts are so remarkable that, were Dr Schaudinn not already known as a very competent investigator of microscopic organisms, we should hesitate to accept them as true. Supposing, as is not improbable, that similar facts can be shown in regard to the trypanosomes of mammalian blood, the conclusions which our medical investigators have based upon a very limited knowledge of the form and life-history of the trypanosomes occurring in diseases such as sleeping sickness, surra, and nagana, are likely to be gravely modified, and practical issues of an unexpected kind will be involved.

As has already been pointed out in this article, the British Government has no staff of public servants trained to deal with the world-wide problems of sanitation and disease which necessarily come with increasing frequency before the puzzled administrators of our scattered Empire. There is no provision for the study of the nature and history of blood-parasites in this country, that is to say, no provision of laboratories with the very ablest and exceptionally-gifted investigators at their head. We play with the provision of an adequate

Dr

army, officers, and equipment to fight disease, which annually destroys hundreds of thousands of our people, much as barbarous states or bankrupt European kingdoms play with the provision of an ordinary army and navy. Their forces exist on paper, or even in fact, but have no ammunition, no officers, and no information; and there is no pay for the soldiers or sailors. Schaudinn, on the other hand, is carrying on his researches as an officer of the German Imperial Health Bureau of Berlin; and the account of them was published in the official Report of that important department of the German imperial administrative service six months ago. It is not possible here to give a full report on Dr

FIG. 4.-TRYPANOSOMA ZIEMANNI, SCHAUDINN.

From the blood of the stone-owl, Athene noctua. This phase of the lifehistory corresponds to the 'crescent-phase' of the malarial parasite Laverania.

a, represents a female or egg-cell (macrogamete); b, represents a male or sperm-mothercell (microgametocyte); n. nucleus; bl. blepharoplast. After Schaudinn.

Schaudinn's work; but it appears that he has studied two distinct species of trypanosoma, both occurring side by side in the blood of the little stone-owl, and already seen, but incompletely studied, by Danilewsky and Ziemann. The second of the two species of trypanosome is in some respects the more remarkable. Schaudinn calls it Trypanosoma Ziemanni; and from the figures which are here given (figs. 4, 5, 6 and 7), copied from his article, with the explanations below the figures, the reader will at once see what Vol. 200.-No. 399.

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an extraordinary range of form and mode of multiplication is presented by this one species of trypanosome. Space will not permit us to comment on these various phases beyond noting how assuredly such forms would have escaped recognition as belonging to the trypanosome history if seen, before Dr Schaudinn's memoir was printed, by any of our medical commissioners blindly exploring round about the diseases caused by trypanosomes in man and mammals.

One very astonishing and revolutionary fact discovered by Schaudinn we must, however, especially point out. Medical men have long been acquainted with the spirillum,

The full-grown trypanosomes seen in fig. 4 have now been swallowed by the common gnat, Culex pipiens, and are undergoing development in its stomach.

A, shows the spermatozoa, Sp., or microgametes, developing as elongated animalcules from the male cell. The large black mass, z, is the stained nucleus of a blood cell of the owl to which the parasite was adherent. B, shows the now rounded egg-cell, Oo, being fertilised by the liberated spermatozoa, Sp. The fusiform mass on the right is a discarded outer coat of the female trypanosome together with the nucleus, z, of a blood-corpuscle of the owl to which it was adherent. After Schaudinn.

or spiral threads, discovered by Obermeyer in the blood of patients suffering from the relapsing fever of eastern Europe. These were universally and without question regarded as Bacteria (vegetable organisms) and referred to the genus 'Spirochete' of Ehrenberg. They were called

Spirochete Obermeieri; and relapsing fever was held to be a typical case of a bacterial infection of the blood. It is now shown by Schaudinn that the blood-parasite spirochete is a phase of a trypanosome (fig. 7); that it has a large nucleus and a micronucleus or blepharoplast, neither of which are present in the spiral Bacteria; and, further, that it alters its shape, contracting so as to present the form of minute oval or pear-shaped bodies, each provided with a larger and a smaller nucleus. These oval bodies are often engulfed by the colourless corpuscles (phagocytes) of the blood; and it is in the highest degree probable that in this condition they have been observed in some tropical diseases without their relation to the spiral

Further phases of Trypanosoma Ziemanni after fertilisation, which are found in the intestine of the common gnat, Culex pipiens.

a, corresponds to the vermicule phase (ookinete) of the malaria parasite. It is the fertilised egg-cell, now elongated and active in movement. The nucleus is seen, and within the nucleus is the blepharoplast. b and c, elongation and coiling of the ookinete with multiplication of the nucleus corresponding to the formation of the spore-holding cysts of the malaria parasite which are attached to the gut-wall of Anopheles; d, breaking up of the coil into small neutral trypanosomes (neither male nor female). From Schaudinn.

forms being suspected. The corpuscles lately described by Leishman, in cases of a peculiar Indian fever, are very probably of this nature, as are also similar bodies recently described in Delhi sore. On the whole, it may safely be said that the researches of Dr Schaudinn, of which only a preliminary account has yet been published, have widely modified our conceptions as to these blood

parasites, and must lead to important discoveries in regard to diseases caused by them in mammals and in man.

The facts that wild game serve as a tolerant reservoir of trypanosomes for the infection of domesticated animals by the intermediary of the tsetze fly, and that native children in malarial regions act the same part for the malarial parasite and mosquito, suggest very strongly that some tolerant reservoir of the sleeping-sickness trypanosome may exist in the shape of a hitherto unsuspected mammal, bird, or insect. The investigation of that hypothesis and the discovery of the reproductive and

Forms of small neutral trypanosomes belonging to the series of T. Ziemanni found in the malpighian tubes of the common gnat. That marked a is also found in the owl's blood, where it is introduced by the bite of the gnat and multiplies by fission, eventually giving rise to the full-sized sexual forms of fig. 4. These small elongated forms are what have been called Spirochata, and confused up till now with the bacterial parasites known as Spirillum.

a, nentral Spirochaeta-phase showing, n. nucleus and, bl. blepharoplast; b, a smaller individual dividing by longitudinal fission into two; c, a similar individual with the two newly formed fission products extended in line; d and e, further longitudinal fission in progress; ƒ, a smaller Spirocheta-phase; g, resting state or contracted condition of the same; h, resting state of a four-fold individual such as e; i and k, star-like agglomerations (such as are well known in Trypanosoma Lewisii, Brucei, and equinum) due to a coming together of free individuals and not to a fission or budding process. After Schaudinn.

secondary forms of the mammalian trypanosomes are the matters which now most urgently call for the efforts of capable medical officers. But we must not be sanguine of rapid progress, since men of the scientific quality