The Authors have studied the influence of angle televisive spectacle on both angle and amplitude of visual fusion in 50 twins. Television appeared to produce an increase of the simultaneous macular perception and a marked change of fusional convergence and amplitude. Furthermore, it increases the fatigability of individual convergence.

The twins method, employed by the Authors, has demonstrated that the televisive effect acts on a hereditary background, involving also hereditary mechanisms.

We have studied, in this work, environmental variability in twins, including the influence of age on the morphological and functional, physical and psychical characteristics.

I. Morphological Characteristics

1. For anthropometric measurements, most of the measurements of the cranium and of body lenght reveal a relatively high similarity between MZ twins, i. e. a high hereditary conditioning and low environmental influence. Most measurements of body volume and weight indicate instead a wider percentile intra-pair difference in MZ twins, indicating higher environmental susceptibility. Among constitutional indexes, Pignet-Vervaecksche's index appears to undergo the highest hereditary conditioning.

2. The heart, the first section of the aorta, the lungs, thorax and stomach were examined radioscopically. Their shapes appeared largely conditioned by heredity. Their measurements (obtained by telefilms) are, in part, conditioned by heredity.

3. The vessels of the retina and the capillaries of the skin are also conditioned by heredity.

4. Finger and palm ridges clearly show similarity in MZ twins. Examining MZ twins belonging to different age groups we have found that similarity of finger ridges was higher in MZs between 6 and 8 years of age than in later age groups.

5. As for blood cells, their size is largely conditioned by heredity, but also highly susceptible to environmental influences. The Hemogram and the Elmonogram of the leucocytes are, to a certain degree, conditioned by heredity. No clear appraisal could be made of the influence of heredity on the blood platelets count and on the reticulocytes.

II. Functional Characteristics

6. Body function as a whole.

A study of 30 families, belonging to a 290 individuals pedigree, showes that the epithelioma adenoides cysticum is genetically influenced by an autosamal dominant factor. But, owing to penetrance differences between sexes, apparently the disease is irregularly transmitted.

The authors describe a new hereditary dystrophy of the cornea, the specked heredo-dystrophy of the corneal parenchyma. In the corneal stroma of both eyes speckles can be easily distinguished; they are more or less numerous and can be found in all the layers of the parenchyma, as well in the center as at the periphery. Dimension, shape and density of the speckles are very variable: they are oval, round or festooned; some of them are opaque at the borders; others show a more diffuse trouble; others are dotted; their borders are well-cut, regular or indented. In optical section the opacities are thin and flat. This dystrophy is not evolutive and is transmitted as an autosomal regular dominant trait. One member of the affected family shows a cloudy central dystrophy of the corneal stroma, so that it is possible that there exists a relationship between these two affections.

The difference in nuclear structure between male and female tissues in man has been examined in liver tissue from three embryos of each sex. The so-called sex chromatin consists of a large heterochromatic segment of the X chromosome, thus existing in duplicate in female diploid cells. The two segments have a tendency of juxtaposition resulting in a larger heterochromatic body in female than in male cells. Beside the large heterochromatic segment the X chromosome has, in the tissues studied, a euchromatic segment attached through a small terminal heterochromatic knob to a nucleolus. In male cells the euchromatic segment of the X chromosome is often joined terminally to a small heterochromatic segment believed to belong to the Y chromosome.