The American Journal of Tropical Medicine and Hygiene - Volume s1-12, Issue 4, July 1932

The present study of cutaneous hypersensitivity to hookworm extract (Necator Americanus) was carried out on the island of Puerto Rico. In the investigation attempts were made to compare: first, the intensity of the skin reaction before and after treatment; second, the skin sensitivity in various age groups; third, to test the specificity of the reaction using as controls extracts of Ascaris lumbricoides, Fasciola hepatica and a common intestinal bacterium, Bacillus (Escherichia) coli.

The adult Necator americanus and Ascaris lumbricoides used in the preparation of the extracts were obtained from hospital patients on treatment. The worms were washed and dried over sulphuric acid, broken up, and finally ground in an agate mortar. Fasciola hepatica were obtained from fresh cattle livers immediately after killing. The bacterium coli extract was obtained by washing off with distilled water a forty-eight hour culture grown on nutrient agar, dried and finally ground.

Before discussing the pathology of amebiasis in carriers, it is necessary to define the term “amebiasis.” By “amebiasis” I understand the state of infection of man with Endamœba histolytica whether symptoms of the infection are present or absent. The term includes the amebic carrier state, those cases presenting mild or atypical symptoms of infection, those presenting diarrhea as a prominent symptom, and lastly, those developing the characteristic clinical picture known as amebic dysentery and the complications known as amebic abscess of the liver and other organs. It will be noted that in this definition amebic dysentery is considered merely as one stage in amebiasis. The conception that the terms “amebiasis” and “amebic dysentery” are synonymous is now obsolete and should be abandoned.

INCIDENCE OF INFECTION The numerous surveys that have been made in the United States and other countries for the purpose of determining the incidence of infection with Endamœba histolytica have demonstrated that it has a world-wide distribution.

A medium suitable for the cultivation of Endamœba histolytica is provided by adding whole wheat flour to a 0.1 per cent extract of heart muscle. The advantages of the medium are: (a) the ease of preparation and low cost, (b) the small number of bacteria that grow in it, (c) the longevity of the amebae, and (d) the availability of it for the study of the effects of drugs.

One of the difficult problems of amebiasis lies in the differences observed in symptomatology in the presence of infection with Endamoeba histolytica. It is difficult to explain the increasing tendency to dysentery and hepatic abscess in hotter climates. The same patient for unaccountable reasons may be subject to alternating diarrhea or dysentery, and constipation. Maintenance of host-parasite balance is often difficult to attain and maintain. Response to treatment shows great variability. Amebiasis clinically is a protean disease.

Various explanations have been attempted for this situation. It has been assumed that certain climatic factors influence the the host or the parasite in an unknown way. Brumpt 2 has suggested that quadri-nucleated cysts may be divided on the basis of animal pathogenicity into three species, which he designates E. dysenteriae, E. hartmanni and E. dispar. He believes that the first of these predominate in warm climates and the latter two in cool climates.

Experiments are described whereby the vitamin A content of white and yellow yams are determined.

The white yam contains approximately 0.25 unit per gram while the yellow yam contains 1 unit per gram.

Coconut water is taken by the people of Porto Rico both as a refreshment and as a diuretic. This latter use is probably based on tradition as no literature has been found which proves that coconut water is physiologically active in this respect. This paper is concerned with a study of two of the factors of the vitamin B complex content of the coconut water, viz., vitamins B (B1) and G (B2).

EXPERIMENTAL The experiments were conducted according to the methods of Sherman and Spohn (1) and Sherman and Axtmayer (2) for the quantitative determination of vitamin B complex values. These methods involve placing healthy young albino rats when twenty-eight to twenty-nine days old upon a vitamin B complex-free diet which is not only adequate but approximately optimal (for growth of rats) in all other respects. The basal diet consists of purified casein, 18; Osborne and Mendel's salt mixture, 4; butterfat, 8; cod liver oil, 2; and cornstarch, 68 per cent.

This work is a revision of the “Handbook of Medical Entomology” by these authors which appeared in 1915. It deals with the structure and recognition, biology, taxonomy, disease relationship and control of arthropods of medical importance.

The present form is far more attractive, in several respects, than the earlier edition, which met with such a cordial reception. There is a much improved arrangement of the material, treating the various groups in their systematic (natural) order. The information concerning each group is brought up-to-date by an excellent digest of the literature and the value of this is enhanced by a bibliography covering 30 pages at the end of the text. The book is fully illustrated with 184 figures of which about 50 are original. In general there is a slightly better reproduction of these than in the earlier publication. Rather elaborate keys are given and with their included illustrations extend over 60 pages of the text.

In their Preface the authors state that this book has been written especially for the medical student and the medical practitioner in the tropics and more temperate climates. A careful reading of the book convinces one that it should prove of great service to both student and practitioner, as the descriptions of disease are clear, adequate for the purpose intended, and the illustrations, although mostly reproductions, are well selected and printed, though some of the halftones have suffered from reproduction. The work is remarkedly up to date in the recording of the results of recent research upon the diseases considered, and for this reason, is of special value to the medical student.

The inclusion of amebiasis in a work treating of tropical fevers is somewhat unusual but as fever is a symptom of some forms of this infection, its inclusion is, after all, justified.