Obrázky stránek
PDF
ePub

SECTION ON GENERAL MEDICINE.

1. Malarial Fever and Its Expense to the People of Texas. Albert Woldert, M. D., Tyler.

2. A Case of Malarial Cystitis-Parasites in Blood Cells of

Urine.

Robert Westphal, M. D., Yorktown.

3. Some Observations on Malaria.

Jno. T. FitzSimon, M. D., Castroville.

4. The Medical Side of Appendicitis.

R. T. Morris, M. D., Houston.

5. The Signs and Pathology of Pleural Lesions.

A. E. Thayer, M. D., Galveston.

6. Cardiac Neuroses-The Necessity of Their Proper Diagnoses. Green L. Davidson, M. D., Wharton.

7. The Advantages and Use of the Microscope in General Prac

tice.

J. W. McLaughlin, M. D., Galveston.

8. Pneumonia in Our Penal Institutions.

W. E. Fowler, M. D., Huntsville.

9. The Use of Anti-streptococcic Serum in the Treatment of Mixed Infections of Tuberculosis and Streptococci.

Otto Ehlinger, M. D., La Grange.

10. The Conveyance of Yellow Fever.

U. S. Surgeon H. R. Carter, M. D.,
Baltimore, Md.

11. An Outbreak of Yellow Fever in DeWitt County.
J. M. Reuss, M. D., Cuero.

12. Yellow Fever-The Laredo Epidemic.

Robert L. Dinwiddie, M. D., San Antonio.

MALARIAL FEVER-ITS EXPENSE TO THE PEOPLE OF TEXAS.

ALBERT WOLDERT, M. D., TYLER.

The True Cause of Malarial Fever.-No scientist familar with the microscope can at the present day doubt that the accidental discovery of the malarial parasites in the red-blood corpuscles of man by Laveran in 1880 is the true cause of malarial fever.

The quickest and the best way to determine whether or not a patient has malarial fever is to procure a drop of blood and examine it under the microscope with a 1-12 oil-immersion lens. If the malarial parasite be found, there can be no question as to the diagnosis. The quinin or "therapeutic test" is uncertain, and requires two or three days to settle the question of diagnosis, while the microscope can determine this question within five minutes.

According to the belief of the Italians, with Golgi at the head, there are three different types of human malarial parasites which produce the different types of chills and fevers, namely, the tertian, the quartan, and the estivo-autumnal. Most Americans have adopted this classification. Thayer and Hewetson, of Baltimore, deserve great credit for their original work on this subject, and entitled "The Malarial Fevers of Baltimore," and though now it is nearly ten years old, their book is one of the very best which has ever been written on malarial fever.

How the Malarial Parasite is Conveyed From Man to Man, and How it is Perpetuated.—This germ of malarial fever is an animal organism, and in this respect is different from the tubercle bacillus, the cholera bacillus, and other bacteria which may be called vegetable organisms. In fact, the malarial parasite has been classified2 into a natural order (gymnosporidia), a class (sporozoa) into different genera (a-Hemameba, and b-Laverania), and into dif ferent species; hemameba malarie (quartan), hemameba vivax

(tertian), and hemomenas precox (remittent fever-Ross), and it has been further proved that some of the malarial parasites are of different sexes. These malarial parasites (protozoa, hematozoa, gymnosporidia, gametocytes, sporozoa, hemameba), found in the red-blood corpuscles of man during the existence of malarial fever, are not normal constituents of the blood. They are harmful parasites in the truest sense of that word.

The malarial parasite (in the form of round bodies) probably spends its winters in the blood of those cases of malarial fever who have never been cured, and in infected mosquitoes (in the form of spores). I have found the malarial parasite in the blood of man during the month of February and after freezing weather (American Journal Medical Sciences, March, 1903). It can be said that this malarial parasite does not complete its entire life-cycle in the blood of man, but only a part of this cycle, and if it had no other host in which to grow and develop than in the blood, it would doubtless perish, and there would never more be any malarial fever. Unfortunately, however, the malarial parasite has selected another host to complete its existence, and this is the mosquito of the genus Anopheles. This question has been settled positively within recent years, though some relationship had been suspected to exist between them from antiquity. Thus Nuttall states that almost 2000 years ago Roman writers, among whom were Varro, Vitruvius and Columella, suggested that some relationship might exist between mosquitoes and certain diseases. Sydenham,* nearly 300 years ago, wrote: "That when insects do swarm extraordinarily, and when fevers and agues (especially quartan) appear early, as about midsummer, then autumn commonly proves very sickly."

However, none hit upon the true method of the dissemination of the disease until Dr. Patrick Manson," in 1894, fully explained to Dr. Ronald Ross the complete details of his theory. So firmly convinced did Ross become that he agreed to make a practical test of this question. Manson prevailed upon the British government to despatch Ross to India, where his work was carried on. We

next find Ross, in April, 1895, at Secunderabad, India, busily engaged in this work." Arriving, however, too late in the season to study human malaria, he began to study the malarial parasite of birds, or protosoma-Labbé. As in all original work, we find that the path of Ross was not strewn with roses. He made a note as follows: "As a matter of fact, for nearly two years and a half my results were almost entirely negative." He could not obtain the correct scientific names of the mosquitoes, and, consequently, used names of his own. Mosquitoes of the genus Culex he called "grey" and "brindled," and those of the genus Anopheles he called "dappled winged."

Cultivation of Malarial Parasite of Birds in the Mosquito (Culex). On March 11 and 12, 1898, Ross placeds within a cage (covered over by mosquito bar) certain birds whose blood contained malarial parasites. Inside this cage he liberated a number of mosquitoes, which bit the birds, and on March 13th he began to dissect these mosquitoes. Out of a number of those dissected he only found one which had become infected with the malarial parasite of birds. Through the courtesy of a loan made me by Dr. Ronald Ross, now of the Liverpool School of Tropical Medicine, I am able to present one of his first and very best specimens, which shows the zygotes of bird malaria that had developed within the middle intestine of the mosquito. (See Figs. 1, 2 and 3.) Note. The zygote is a further developmental stage of the malarial parasite. Spores develop within the zygote after several subsequent days' growth. It was dated Calcutta, India, July 12, 1898. I had the pleasure of presenting the specimen before the Philadelphia Pathological Society, November 8, 1900.

Description of Middle Intestine (Stomach) of Mosquito, Showing Zygotes of Bird Malaria Obtained by Ross.-Description of Plate No. 1.-This specimen shows the entire middle intestine after dissection, with part of the esophagus above, and the attached malpighian tubes, and hind intestine below. Upon examination with (a low power) No. 3 ocular and No. 3 objective (Leitz), with diaphragm well open, at first sight one might be disposed not to

Middle Intestine of Mosquito Showing Zygotes of Bird Malaria Obtained

by Ross.

Zygotes of bird malaria (Protosoma Labbé) seen in the same specimen of dissecte d middle intestine of mosquito (Culex).

[graphic][ocr errors][merged small][graphic][merged small][merged small][merged small][merged small][merged small][graphic][merged small]

Same as plate No. 2, zygotes of protosoma N os. 1, 2 and 3 (same
as plate No. 2) greatly magnified, and diagrammatic, showing
yellowish hyalin capsule and yellowish hyalin oval shaped
masses (fatty granules ?) and vacuoles. Protoplasm has a retic-
ulated appearance and contains reddish pigment granules.

« PředchozíPokračovat »