From George Gulliver 20 January [1856]1
Mount Alton, Templeogue. [Dublin]
Jan. 20, 1855.
My dear Sir,
It is not singular that the Blood-Discs of different genera of birds should be similar, for widely distinct Families have those corpuscles not distinguishable in size, shape, or structure. When a marked difference of shape occurs it seems to be merely aberrant, as in the Snowy Owl, Passenger Pigeon, Snow-Bunting, Great Butcher Bird, Java Sparrow, &c. And so of certain saurian Reptiles. In my Appendix to Gerber’s Anatomy, 8o. Lond. 1842,2 where the details are fuller than in the Notes to Hewson.3 Indeed, the difference of the corpuscles in the entire class of Birds is not more than may be found in a single Family of Mammals.
All I recollect of the cows and goats that I examined is, that they were those most easily got at in London, & therefore probably the most common ones.4
The measurements of the Dog’s corpuscles 13542th, of the Dingo 13395th, & of the Wolf 13600th of an inch,5 seem much more different in figures than in fact, and no greater than might be obtained by reducing the averages of different sets of measurements of the corpuscles of the very same individual, provided the measurements were not confined to a single dried & invariable specimen of blood.
The measurement in the Dog in Hewson was from a little mongrel. I have examined those of a fox-hound and of other good breeds without noting any marked difference. But the corpuscles of the Fox, after many comparative trials, have always proved very slightly smaller than the corpuscles of the Dog.
I am, | Yours very truly, | George Gulliver.
If you want to see a marked difference of size in the corpuscles of a single family of mammals, compare the comparatively minute corpuscles of the smallest Ruminants or Rodents with the larger corpuscles of the largest species of the same order.
CD annotations
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Gerber, Friedrich. 1842. Elements of the general and minute anatomy of man and the Mammalia, chiefly after original researches. Notes and an appendix by George Gulliver. London.
Summary
Discusses the similarity in size, shape, and structure of the blood corpuscles of the Aves. Notes differences between the corpuscles of the domestic dog and some wild species.
Letter details
- Letter no.
- DCP-LETT-1632
- From
- George Gulliver
- To
- Charles Robert Darwin
- Sent from
- Templeogue, Dublin
- Source of text
- DAR (CD library – Gulliver, George 1846)
- Physical description
- ALS 3pp †
Please cite as
Darwin Correspondence Project, “Letter no. 1632,” accessed on 20 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-1632.xml
Also published in The Correspondence of Charles Darwin, vol. 6