Title: A Study of the Chromosomes of the Germ Cells of Metazoa Read Before the American Philosophical Society, January 18, 1901 Classic Reprint
Publisher: Forgotten Books
Publication Date: 2018
Language: English
ISBN 10: 1334421455
ISBN 13: 9781334421457
Binding: PAP
Condition: New
Weight: 182 grams

About this title

Synopsis

Excerpt from A Study of the Chromosomes of the Germ Cells of Metazoa

In the present paper the part containing the general conclusions may appear dispro portionally great to the record of the observations. These observations are to great extent on the number and valence of the chromosomes and chromatin nucleoli from the time of the last generation of the spermatogonia up to the formation of the spermatids. But the determination of these numbers is very difficult; large numbers of sections have to be examined in order to find the necessary stages, and the number of the chromosomes of each stage have to be counted in a considerable number of cells of each species in order to insure accuracy. The counting has been done in all cases by selecting those cells in which the chromosomes are most loosely grouped, being sure at the same time that all the chromosomes are in the plane of the section, drawing the chromosomes carefully with the camera lucida, then counting their number on the drawings. This demands much patience and time, necessitating also constant re'e'xaminations and study of new material, though the results may be tabulated in a very small space. Of course the difficulties are most pronounced where the chromosomes are numerous and small.

The material was collected by me at two localities - ih the vicinity of Philadelphia, Pennsylvania, and in the neighborhood of Wood's Holl, Massachusetts. Great care was taken to insure accurate identification of the species, and my specimens were directly compared by me with the collections in the museums of the Wagner Institute of Science and of the Academy of Natural Sciences of this city; these collections had been labeled by Dr. P. R. Uhler, of Baltimore, our foremost American authority on this group of Insects; and I must also acknowledge my indebtedness to Dr. Uhler for kindly identify ing a number of species which were not represented in the collections just mentioned. To my friend, Mr. C. W. Johnson,…

"About this title" may belong to another edition of this title.

Store Description

We first started out as ?The Paperback Exchange,? a chain of physical bookstores where we would part exchange your beloved books for new stories to transport you to faraway places. However, as shopping started to evolve to online shops and marketplaces, we bid our stores goodbye to become ?PBShop.? This transition has only allowed us to blossom as we now ship thousands of titles to book lovers across the globe. We pride ourselves in being a community of local book lovers which allows our passion and devotion to shine in everything we do. In 2020 we not only celebrated our 20th birthday but our 1st birthday as being completely employee owned after becoming an E.O.T in September 2019. We are proud to be different and embrace standing apart on a book mountain by working from a virtual inventory which allows us to provide thousands of books that may be difficult to get for your bookshelf or your studies. Working with a number of different suppliers allows us to explore other avenues such as puzzles, sheet music and even stationery so we really do have something for everyone. Life is about being versatile in all realms of existence. If this is your first visit or you are a returning customer, we would like to welcome you to the PBShop family, for there is no friend as loyal as a book. We are a company who put our customers at the centre of everything we do as we understand the importance of reading because once you learn to read, you will forever be free. There are a whole lot of things in this world of ours that we are yet to explore, which is why we will forever inspire curious minds.

Visit Seller's Storefront

Seller's business information

Pbshop.co.uk Ltd
Unit 22 Horcott Industrial Estate, Horcott Road, Fairford, GL7 4BX, United Kingdom

Sale & Shipping Terms

Terms of Sale

Returns Policy
We ask all customers to contact us for authorisation should they wish to return their order. Orders returned without authorisation may not be credited.
If you wish to return, please contact us within 14 days of receiving your order to obtain authorisation.

Returns requested beyond this time will not be authorised.

Our team will provide full instructions on how to return your order and once received our returns department will process your refund.
Please note the cost to return any...

More Information

Shipping Terms

Books are shipped from UK warehouse. Delivery thereafter is between 4 and 14 business days dependant upon your location - please do contact us with any queries you may have.

Shipping rates within U.S.A.

Shipping rates within U.S.A.
Order quantity	7 to 14 business days	7 to 14 business days
First item	US$ 0.00	US$ 0.00

Delivery times are set by sellers and vary by carrier and location. Orders passing through Customs may face delays and buyers are responsible for any associated duties or fees. Sellers may contact you regarding additional charges to cover any increased costs to ship your items.