Report of the Board of Regents Volume 47

Report of the Board of Regents Volume 47

List price: US$13.13

Currently unavailable

Add to wishlist

AbeBooks may have this title (opens in new window).

Try AbeBooks

Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 edition. Excerpt: ... and this position is, I think, strengthened the more broadly we extend our inquiry into all the fields of protoplasmic activity. There are three questions before us. 1. What is the evidence that the germ-plasm and somatoplasm are distinct? 2. What is the specific nature of the germ-plasm? 3. What is the nature of the relations which exist between the two? 1. The separation of the germ-plasm is in the regular order of evolution upon the principles of physiological division of labor. The unicellular organisms combine all the functions of life in a single massof protoplasm, that is, in one cell. In the rise of the multi-cellular organisms the various functions are distributed into groups of cells, which specialize in the perfecting of a single function. Thus the reproductive cells fall iuto the natural order of histogenesis, and the theory of their entire separation is more consistent with the laws governing the other tissues than the theory which we find ourselves obliged to adopt, that while separate they are still united by some unknown threads with the other cells. The morphological separation of what we may call the race protoplasm becomes more and more sharply defined in the ascending scale of organisms. Weismanirs contention as to the absolutely distinct specific nature of the germ-plasm and somato plasm has however to meet the apparently insuperable difficulty that in many multi-cellular organisms, even of a high order, the potential capacity of repeating complex hereditary characters, and even of producing perfect germ cells, is widely distributed through the tissues. For example, cuttings from the leaves of the well-known hot-house plant, the begonia, or portions of the steins of the common willow Iree. are capable of reproducing...show more

Product details

  • Paperback | 398 pages
  • 189 x 246 x 21mm | 708g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236779894
  • 9781236779892