Unna Methods

UNNA METHODS. The first method is for the selective staining of nucleoli with methylgrün-pyronin; 0.15 g of methylgrün and 0.25 g of pyronin are dissolved in a mixture of 25 cm³ of 96% wine alcohol, 20 cm³ of glycerin, and 100 cm³ of a 0.5% solution of carbolic acid for 5 minutes, then the sections are rinsed in distilled water and differentiated in 70% alcohol: nuclear chromatin, mucus, and the basic substance of cartilage are stained green, nucleoli and protoplasm are red. The second method is for the differential staining of plasma cells together with mast cells using polychrome methylene blue: sections or films are stained for 15 minutes with a strongly diluted aqueous solution of polychrome methylene blue; after washing in water they are differentiated with a glycerin ether solution (a few drops on a small cup of distilled water), after which there is a thorough washing in water, dehydration with alcohol, and mounting in Canadian balsam (through xylene or through bergamot oil): the granules of mast cells are stained metachromatically red, plasma cells are stained blue. In the absence of glycerin ether, another modification can be used: staining with a diluted solution of methylene blue, washing in distilled water, differentiation, and simultaneous dehydration in a 74% neutral solution of orcein in ethyl alcohol for 1 to 10 minutes depending on the staining power of the orcein; then absolute alcohol and mounting in balsam, as above. WALLACE Alfred Russel (1823-1913), the famous English naturalist, traveler, and zoogeographer, who independently of Darwin arrived at the idea of evolution by natural selection. In his youth, Wallace studied geodesy and engineering art, was a teacher for 4 years, and was engaged in collecting plants and insects. In 1848, Wallace left with Bates for America and spent 4 years in the Amazon Valley. The ship on which he was returning to England caught fire in the ocean, all his collections were destroyed, and he himself barely survived. In 1854, Wallace went to the Malay Archipelago, where he spent 8 years studying its geology, flora, and fauna. These studies led Wallace to the idea of the variability of organisms depending on geological changes. In 1858, Wallace wrote and sent Charles Darwin an article "On the tendency of varieties to depart indefinitely from the original type." At the advice of Darwin's friends, this article, which in ideas fully coincided with Darwin's theory of natural selection, developed by him since 1842, was presented at a meeting of the Linnean Society and printed in its proceedings together with a small article by Darwin on the same question. Upon returning to England, Wallace began to process his richest collections and develop a number of problems of biology, animal distribution, and evolution. A wonderful description of his journey was published under the title "The Malay Archipelago, the land of the orangutan and the bird of paradise." In 1876, Wallace published "The Geographical Distribution of Animals," an extensive work full of profound thoughts, where he carefully collected and developed his vast material on the methods of animal distribution, their wandering, and the influence of physical conditions on distribution, and where an overview and characterization of zoogeographic regions and their subdivisions are given. This work is followed by "Tropical Nature" (1879) and "Island Life" (1880). Evolutionary questions are more developed in the books: "Natural Selection" (1870) and "Darwinism" (1889). The first book is a collection of articles for 15 years; among them, the articles on mimicry and protective coloring of Malayan butterflies and the "theory of bird nests" are especially important, where Wallace acts as an opponent of Darwin's sexual selection, attributing the modest coloring of female birds to the action of natural selection. In the second book, Wallace expounds the theory of natural selection, dwelling more on the variability of species in the natural state and on the coloring and ornaments of animals. - Despite his immense merits in the propaganda and development of Darwinism and especially in the development of the doctrine of the geographical distribution of organisms, it must be noted that Wallace, along with the evolutionary process, illogically admitted the intervention of the "invisible world" in it at the emergence of sensitivity and consciousness in organisms and especially at the development of mental and moral peculiarities of man.