Volume 1

A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling.

Landois, L. (Leonard), 1837-1902. Lehrbuch der Physiologie des Menschen. English

Date:: 1891

Credit: A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling. Source: Wellcome Collection.

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$17 [A delicate plexus of fibrils—intra-imclear plexus—exists within the nucleus just as in other cells. It is very probable that the pro- toplasm itself is pervaded by a similar plexus of fibrils, and that it is continuous with the intra-nuclear plexus (fig. 15).] The colourless corpuscles divide by mitosis, and in this way reproduce themselves. The Number of Colourless Corpuscles is very much less than that of the red corpuscles, and is subject to considerable variations. It is certain that the colour- less corpuscles are very much fewer in shed hlood than in blood still within the blood-vessels. Immediately after Fig. 15. blood is shed an enormous number of white corpuscles Plexus of fibrils in a colour- disappear (§ 30). less blood-corpuscle. Al. Schmidt estimates the number that reinain at of the whole originally present in the circulating blood. The proportion is greater in children than in adults. The following' table gives the number in shed blood :— ° Number of White in Peopoktion to Red Blooi>-Corpuscles. In Normal Condition. In Different Places. ; in Different Conditions. 1 : 335 ( Welcker). 1 : 357 {Moleschott). Splenic Vein, 1 : 60 Increased by Digestion. Loss Splenic Artery, 1 : 2,260 \ of Blood, Prolonged Sup- Hepatic Vein, 1:170 puration,Parturition,Leuk- Portal Vein, 1 : 740 semia. Quinine, Bitters. Generally more numerous Diminished hj Hunger, Bad in Veins than Arteries. ! Nourishment. [The number also varies with the Age and Sex :■— Age. Sex. White. Red. General Conditions. White. Red. Girls, .... Boys, .... Adults, Old Age, . 1 : 405 1 : 226 1 : 334 1 : 381 While fasting, After a meal . During pregnancy, 1 : 716 1 : 347 1 : 281] resemble the movements of amoeba) con- sist in an alternate contraction and relaxa- tion of the protoplasm surrounding the nucleus. Processes are pushed out from the surface, and are retracted again (fig. 16). There is an internal current in the protoplasm, and the nucleus has also been observed to change its form [and exhibit contractions without the cor- puscle dividing. The mitotic aster, and convolution of the intra-nuclear plexus have been seen]. Two series of phenomena result from these move- ments:—(1) The wandering or locomotion of the corpuscles due to the extension and retraction of their processes; (2) the absorption of small particles into their interior (fat, pigment, foreign bodies). Fig. 16, Human leucocytes showing amoeboid movements. The particles$