Contains real wooden plates by different species of trees (transverse, radical and tangential sections)

Filariasis surveys made during 1962-63 in 5 villages in American Samoa among persons over 5 years of age gave an elephantiasis rate of 3.4%, a microfilarial rate of 26% and a median microfilarial rate (MfD(50)) of 29. These rates were somewhat higher than those found in surveys made in the ...

The final cause of nerve-cell destruction during infections with Trypanosoma cruzi has not yet been definitively established. It seems that a cytotoxic or cytolytic substance contained within the leishmania forms is probably liberated after their disintegration and acts, mainly at a short distance and in high concentrations, on the ganglion ...

The author reviews the natural history of the tick vectors of American spotted fever. The discussion concerns the ecology of the Rocky Mountain wood tick, Dermacentor andersoni, the American dog tick, Dermacentor variabilis, and the lone-star tick, Amblyomma americanum, all of which are proven vectors of Rocky Mountain spotted fever ...

Recent interest in mathematical descriptions of the epidemiology of helminth parasites has prompted several attempts to obtain quantitative estimates of reproduction and survival at all stages in their life-histories. The availability of microfilarial counts, repeated on many people over 4(1/2) years, suggested that these estimates could be made for Wuchereria ...

Fragments of a boll of Gossypium hirsutum L. from archeological excavations near Tehuacán, Mexico, prove that this species existed in 5800 B. C. No doubt remains that American tetraploid cotton species originated through natural hiybridization.

In isolated skins of Leptodactylus ocellatus the short-circuit current is smaller than the sodium net flux and this difference disappears when the skins are bathed in solutions in which the chloride ions have been replaced by sulfate or methylsulfate ions. There is a net movement of chloride ions from outside ...

A method has been developed for the assay of the odorous attractant of the cockroach, P. americana. The method, called the counterpoint test, employs two matched groups of roaches and provides for a simultaneous titration of standard and unknown. It has a statistical error of +/-40 per cent at a ...

v.1. Timber. American forest operations and increase of European productivity.-- v.2. Ecology of American forest species erosion and reafforestation

A la cabeza del título: U.S. department of commerce. Harry L. Hopkins, secretary. Bureau of foreign and domestic commerce. N. H. Engle, acting director ...