development, however lacking in exactness one's memory may be. It was very rarely that I found it necessary to seek the aid of other eyes to find my place, or to recall the form which I had given to any preceding sentences. Frequently I suspended the editorial work in the midst of the development of an idea. I left the sheet in the machine and sometimes after an interruption of forty-eight hours, or even more, took up the thought again without hesitation at the point at which I had left it. Moreover, I did not deprive myself of the opportunity of correction. The editing over, I had the matter read to me as many times as was necessary, dictating to my secretary modifications and sometimes very numerous additions, and adding everywhere a thousand finishing touches. I believe that I can say that my style was not less imperfect when I wrote the first draft in "braille." On the contrary, if it was perhaps a little more vigorous, it was also rather stiffer.

Finally, and this is what I particularly wish to note, the elaboration of these 1,250 very compact pages did not by any means cause me the prodigious labor that one might naturally expect. The one part which was long and tedious was the extensive preparation, all that which did not appear, the documentation which served as the basis of the work. I retain the hope that anyone who has followed my exposition is convinced that the undertaking can be carried on without any great difficulty and that the methods which are open to the blind lend themselves perfectly to its accomplishment. They have given me, I believe, means of conforming exactly to the course that any person who can see, desiring to treat of the same subject with accuracy, would be compelled to follow. In all my proceedings I have invented nothing. Any person with sight would, I think, be compelled to use some form of memoranda analogous to mine. I simply adapted a common and almost necessary method, I may say, to the special conditions of the blind. This adaptation was a very simple one and did not demand any great effort of the imagination. It was developed little by little, by successive steps, in accordance with the needs. It sprang in a certain way from circumstances.

My design, as one may suppose, is not to incite the blind to engage in the production of works of erudition. To succeed in this it is absolutely necessary to have the taste, the passion for learning, and most fortunately few persons are afflicted with this malady. What a strange life it would be if we were all metamorphosed into bookworms! Very fortunately, too, there are other works more accessible to the blind in which they have less trouble in rivaling those who can see. In all that I have recounted it is not necessary to see an example, but an experience—an experience which, certes, will not surprise the blind (who, at least, will see that everything here men

tioned is quite simple), but may, perhaps, suggest to them some useful observations on certain applications of their own peculiar methods of work. It is, however, addressed especially to those who have sight. With so many other experiences which are renewed every day, it will contribute, perhaps, its little part to inspire them with more equitable judgments on the blind. It requires such an unending array of facts to combat a prejudice and to cause it to retreat step by step that we can never have enough. This will serve as one among many. Let us also hope that it will make an impression on the ranks of the enemy and work for the common welfare.

In conclusion, it remains for me to excuse myself for having spoken at such great length about my own affairs, but if the “I” (that of Montaigne excepted) is nearly always objectionable, the reader will pardon me when he notes that, in spite of appearances, I have mentioned much less regarding my own personal work than regarding that of the blind in general. What I have done any other blind person might have done in my place. Our methods of work are common to all. I have wished, by means of one example, to show the flexibility of our methods. Perhaps, after having read the foregoing, all will understand better how much we appreciate the inventor of an alphabet to which we owe the major part of our culture and our intellectual pleasures.

THE RELATION OF MOSQUITOES, FLIES, TICKS, FLEAS, AND OTHER ARTHROPODS TO PATHOLOGY."

By G. MAROTEL.

It is a matter of common knowledge to-day that while there are many arthropods which live a free life, there are also many others which are parasites, causing in man and also especially in the domestic animals many and varied diseases, the origin and nature of some of which have been known for a long time. It would be banal to recall that phthiriasis is caused by lice, and that certain larvæ of Diptera, such as the œstrids, may occasion the disease called myasis.

This old pathogenic rôle, which has been taught to all the medical and veterinary generations of our time, is quite true. But it is not of this that I wish to speak. It is of a new rôle, brought to light only within the last ten years, the importance of which now grows greater every day, for scarcely a month passes, I might almost say not a week, that some work does not appear which adds some unknown fact or new theory relative to it.

It has to do with one of the questions which in the whole range of parasitic pathology can, with the greatest right, claim to be of practical importance. The danger from the arthropods is a direct consequence of their habits. It only exists in connection with those whose habits are to seek association with men and domestic animals, to bite them and to suck their blood.

Everyone knows that a number of species, such as mosquitoes and gadflies, pass a considerable part of their time in flying from one victim to another, in the same manner that bees wander from flower to flower. Let us suppose, then, that in the course of these wanderings one of them happens to fasten itself on an individual affected by a parasitic or bacterial disease, the agent of which lives in the blood. In sucking the blood it absorbs also the germs which are contained in it, and thus is infected. Should it then attack a healthy person there is danger that it will inoculate him with the disease. This is why

@ Translated by permission from Annales de la Société d'Agriculture, Sciences et Industrie de Lyon, 1906, pp. 279-302.

the biting and sucking arthropods (I insist on these terms) recently considered as being simply troublesome, vexatious, uncomfortable, and disagreeable, have to be looked upon to-day as capable of becoming carriers of infection, agents for the propagation and dissemination of disease. This is why it will be understood henceforth that man and the domestic animals are exposed to certain affections, the germs of which are introduced by invertebrate blood-suckers which they have previously drawn from the sick vertebrate.

Such is the method of this new rôle, which I wish to try to explain here and which modern researches have shown to be of more consequence, especially in warm countries, than could have been suspected previously; so much so that the value of our colonial domain is subordinated (the word is not too strong) to the discovery of the proper means of neutralizing the pathological action of these animals.

Thus, these arthropods, which ten years ago had only an ordinary and purely zoological interest for us, have assumed prime importance both from a medical and a hygienic point of view, and especially in tropical countries. The principal forms connected with the latest discoveries belong to the order Diptera, or to the family Ixodidæ. It has now been established that they are the sole agents of inoculation of seven different maladies, namely, malaria, filariosis, yellow fever, trypanosomiasis, plague, piroplasmosis, and spirochaetosis.

A. PALUDISM, OR MALARIA.

Commonly called malaria, intermittent fever, swamp fever, or simply “fevers," paludism is, according to unanimous opinion, the one human disease which more than any other prevents the acclimatization of Europeans in warm countries. It is due to the invasion of the blood by extremely small sporozoans lodged in the red blood corpuscles, whence is derived the name of endoglobular hæmatozoans, which it is the custom to give them. They belong to the genus Plasmodium and comprise many species, such as Plasmodium malaria, the agent of quartan fever; Plasmodium vivax, the agent of tertian fever; Plasmodium præcox, the agent of irregular, or spring and fall fever.

For a long time it was not known to what these fevers were due. Some said that they were due to marshes, whence the name paludism. It was also said that they were derived from the air, whence the name malaria, which means "bad air." Finally, it was said that they came from the soil, whence the name tellurism, which was also applied to the disease.

None of these was correct. All the etiological conceptions were wrong, and yet mankind for twenty centuries rested on these false

theories of which to-day nothing remains. The first ray of light appeared in 1880, at which date one of our members, Laveran, discovered at Constantine the hæmatozoan which to-day bears his name (fig. 1). But the veil of obscurity which enveloped this important question could not be completely dissipated until 1898.

It was at this time that a group of students, at the head of whom should be placed Grassi and Manson, demonstrated in an irrefutable manner that the parasite of malaria was introduced into man by mosquitoes; that is, passed from man to the mosquito and from the mosquito back to man again, and thus on indefinitely, without being for a single instant, even the thousandth of a second, liberated into the external environment. Consequently, in spite of what was thought for centuries, none of these mediums, neither the air, the water, nor the soil, can cause malaria, and these beliefs become henceforth a part of the history of medicine.

FIG. 1.-Red corpuscle, containing a hæmatozoan of human malaria (Plasmodium malaria).

There is one extremely important fact: Not all species of mosquitoes can propagate malaria; only those which, in the family Culicidæ,

belong to the tribe Anophelinæ can assume this rôle, and the most dangerous of the species from this point of view are first of all the Anopheles maculipennis, which is by far the most redoubtable; then A. pseudopictus, A. superpictus, A. bifurcatus, A. funestus, and finally a last species, Pyretophorus costalis.

The proofs which one can give to-day of the mosquito theory are three. The first is that of Grassi, who, in 1898, in association with Bignami and Bastianelli, was able to follow the evolution of Plasmodium day by day in the bodies of mosquitoes which had been made to suck blood affected by malaria, showing thus that the parasite could penetrate the insect, remain there a certain (After Neveu - Lemaire.) t, time, and then leave to pass immediately to These students have also established the fact that while in the Anopheles, the hæmatozoan undergoes profound transformation, constituting a veritable evolution, and that the intimate mechanism of the transmission was as follows: The parasites sucked in with the blood lay eggs in the stomach, which eggs encyst themselves in the walls of the stomach, and produce a multitude of little vermicular spores. These, set at liberty

FIG. 2.-Head of a mosquito.

Proboscis; p, maxillary palpæ; a, antennæ.

man.