Dark Secrets Research Articles

Ultrastructure of the caecum of Polystomoides malayi Rohde and P. renschi Rohde (Monogenea: Polystomatidae)

The caecal epithelium of Polystomoides malayi and P. renschi consists of two types of cells. Both have granular endoplasmatic reticulum and Golgi complexes. One type has surface lamellae, many large vacuoles with dark secretion, and small vesicles as well as an extensive system of tubular structures in its apical half. The second type contains numerous small medium sized and rarely large vesicles with some granular secretion predominantly near its surface; it is without surface lamellae. The epithelial cells are joined at the surface by zonulae adhaerentes. Secretion in P. renschi is apocrine and holocrine, i.e. portions of cells or whole cells with nuclei of the first type are found in the lumen.

Determination of parous rates in Phlebotomine sandflies with special reference to Amazonian species

Previous work on Phlebotomines has shown that most parous flies in many species may be recognised by the dark residual secretion in the accessory glands; parity can be confirmed by inspection of ovarioles. In the present study 12 species of Lutzomyia were caught in forests near Belém, Brazil, mainly with rodent-baited oil-traps. Many females of the predominant species, L. flaviscutellata (Mangabeira), were parasitised by the protozoan Monocystis. Parous rates based on examination of ovaries were subject to an error of about 5% due to diminution or disappearance of follicular relics. Two successive dilatations of the tunica were seen in L. davisi (Root), suggesting that it had laid two batches of eggs. Biting rates by parous flies varied little during the night, and were somewhat less than those of nullipars. In eight species the dark-gland rate approximated to the parous rate as shown by the ovaries; a small error may have been due to discharge of all secretion, disappearance of follicular relics and premature activity of glands. In contrast to this concordant pattern, four species showed discordance, possibly due to autogeny. It seems advisable to omit oil-trapped blood-fed flies when estimating parous rates by examining glands. Monocystis may increase the dark-gland rate, but it is non-pathogenic or has little effect on life span, and does not hinder blood-sucking.

Diel periodicity in spermatophore formation in the house cricket, Acheta domesticus (L.)

Male house crickets reared individually at 28 °C developed a diel periodicity in spermatophore formation, which consisted in loss of the spermatophore during the dark period and secretion during the light period. The periodicity became established only after most of the insects had formed at least two spermatophores in a random way with respect to light conditions. When periodicity was established, rearing the insects in continuous light resulted in the retention of the spermatophore by nearly all insects. Stridulation began in all experiments at the time of first spermatophore formation.

The fine structure of mammary glands of lactating rats, with special reference to the apocrine secretion

The mammary gland of lactating rats was observed with the electron microscope. The cytoplasm of glandular cells contains parallel-arranged cisternae of well-developed rough endoplasmic reticulum. The Golgi apparatus is also well developed and contains small dark secretion granules of a protein nature. In the basal cytoplasmic area small fat droplets occur in the vicinity of an accumulation of tubular or vesicular elements of smooth endoplasmic reticulum, which is thought to be correlated with the elaboration of fat droplets. Fat droplets push up the luminal surface membrane, and protrude into the lumen. The plasma membrane constricts the cytoplasm slightly below the fat droplet. Some proteinaceous secretion granules encased in vacuoles are contained in the cytoplasmic husk around the fat droplet. Therefore, the protein granules as well as fat droplets are released by the mechanism of apocrine secretion, in which a small amount of the cytoplasm and plasma membrane may be also extruded.

Epithelioma and fibrosarcoma of the penis occurring simultaneously.

The simultaneous combination of fibrosarcoma and epithelial carcinoma in the same penile lesion has not been reported previously. Because of this the following case history is of interest. REPORT OF A CASE A 70-year-old white man was admitted to the Presbyterian Hospital on May 17, 1951, with the complaints of a swelling of the glans penis, which he had noticed two weeks earlier, and hemorrhage on two occasions from beneath the prepuce. For the past 30 years, the patient could not retract the prepuce. The patient was moderately obese and did not appear ill. Examination of the external genitalia revealed a stony hard mass 2 cm. in diameter on the left dorsal aspect of the glans penis beneath the prepuce. A dark brown serous secretion oozed from beneath the prepuce. There were no palpable inguinal lymph nodes. The testes were slightly atrophie. The prostate was normal per rectum. The remainder

Immigrants and American Agriculture

While agriculture is peculiarly an industry of the native born, men of foreign birth have always held an important place in American farming. Before 1900 the Federal Census Bureau gathered very few facts concerning the nativity of farmers, or at least kept them a dark secret. In 1909 the Federal Immigration Commission provided for a tabulation of the more important facts of the 1900 census concerning farm workers. Since then certain data for 1909 and 1919 have been put in order with sufficient accuracy to permit some generalizations. Census data regarding farm laborers, who make up about one-half of all farm workers, are very meagre, however, and such as we have are found in statistics of occupations and not in the statistics of agriculture. Moreover, while all foreign-born are plainly enough immigrants of one sort or another, their children, whether born here or abroad, are for many purposes immigrants of sorts, near immigrants, so to speak. The Immigration Commission took pains to study the immigrant and his family, especially to learn how the second generation occupied themselves and how well they melted. Sociological census data of this soft concerning farmers and farm hands are neither abundant nor satisfactory. In 1920, 10.5 per cent of all white farm operators were foreign-born, nearly 600,000 in round numbers. They occupied over 12 per cent of all land occupied by white farmers; 13 per cent of the improved land; real estate worth approximately $9,000,000,000 or 14 per cent of the farm land and improvements operated by white farmers. All of these percentages are somewhat lower than in 1910, due partly to the falling off in immigrant arrivals from 1914 to 1919. In 1900, 15.3 per cent of white male farm operators were of foreign