Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber.

  • Sobotta Johannes, 1869-1945.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    22/476 (page 18)
    tlie niulticollular oro;nni.sm develop. Tlie first embryonal cells wliicli arise from the division of the imj)regnated ovum generally present the s})herical form. This fiinda- mental form ol‘the cell, however, jircsents many variation.s, ac(!oi’ding to the position and function of the difierentiated cells. 'flic Hize of the cell is subject to many variations analo- gous to those of the form. The smallest cells measure oidy ”) n or less, while the largest are visible macroscopic- ally, as for iustaiicc the large ova of many animals. The c.xtreme size; of siuT cells arises only through secondary deposition of food material in the cell-body. Most cells arc microscopi(!, oidy a. few, as the large nerve-cells of .some animals, being visible with the unaided eye. 'fhere an; three essential or principal constituents of th(i cell : (1) The ccU-hody or the protoplasm; (2) the cr/l nne/eas ; (8) the centrosome. Jn addition to these, the cell may also contain other less im])ortant constituents. C.’crtain cells have no nucleus and, when fully ditferen- tiated, no centrosome. Such cells, however, were origi- nally nucleated (homy c])ithclial cells of the epidermis, red blood-cells of mammalia, central fibers of the lens). The non-nuclcated condition represents, therefore, a state of senility, occurring only in highly ditferentiated cells no longer capable of division. (See pages 55 and 229.) The cell protoplasm is an extremely comj)lex albu- minous substance and is the .seat of the vitality of the cell. Many of the vital jihenomcna are not discernible even under a powerfid micro.sco])C ; on the other hand, life phenomena may manifest themselves in ,‘^ome form of motion. d'his movement of the j)rotoplasm may display itscH under the form of the so-called amrhoid motion, which consists of slow changes of form of the ])rotoplasm, readily observed in the colorless blood-cells or leukocytes (see ])age 57), and may result in a locomotion of these cells. By the extension of processes of the leukocytes.