COLOURLESS CORPUSCLES OF BLOOD. 135 



until, in the perfect Insect, very few remain. When the wings are being 

 expanded, however, and are still soft, a few oat-shaped corpuscles circulate 

 through their vessels; but as the wings become consolidated, these corpuscles 

 appear to be arrested and to break down in the circulating passages ; supply- 

 ing, as Mr. N. thinks, the nutrient material for the completion of these struc- 

 tures, which subsequently undergo no change. In the perfect Insect, a differ- 

 ent set of corpuscles makes its appearance ; which is rather analogous to the 

 red corpuscles of Vertebrata. This last fact completely harmonizes with the 

 views already expressed ; since the formative processes are now reduced to 

 their lowest condition in the Insect; whilst the respiration attains its highest 

 grade. 



157. Even in adult animals, however, variations in formative power may 

 be detected; which correspond with variations in the number of the Colour- 

 less corpuscles. Thus it has been observed by Wagner,*' that the number of 

 these corpuscles is always remarkably great, in the blood of well-fed Frogs 

 just caught in the summer season; whilst it is very small in those which have 

 been long kept without food, or which are examined during the winter. In 

 the reparation of injuries, too, which is effected in cold-blooded animals by a 

 process of simple growth without inflammation, it would seem that the Co- 

 lourless corpuscles perform an important part; as they are observed in great 

 numbers, and in a nearly stationary condition, in the vessels surrounding the 

 spot where the new tissue is being formed; apparently having the same action 

 as in the first development of parts altogether new, such as the toes of the 

 larva of the Water-Newt. 



158. A remarkable confirmation of this view of the connection between the 

 generation of Colourless corpuscles in the Blood, and the production of Fi- 

 brine, is derived fiom the phenomena of Inflammation. A decided increase 

 in the normal proportion of Fibrine in the Blood (from 2| to 3| parts in 1000), 

 may probably be looked upon as the essential indication of the existence of 

 the Inflammatory condition. That this production of Fibrine is due to a local 

 change, can scarcely be doubted ; since it is frequently observed to commence, 

 before any constitutional symptoms manifest themselves : and it may be re- 

 garded, in fact, as one cause of these symptoms. Now the microscopic ob- 

 servations of Mr. Addisont and Dr. Williams,! made independently of each 

 other, have established the important fact, that a great accumulation of Colour- 

 less corpuscles takes place in -the vessels of an inflamed part : this seems to 

 be caused at first, by a determination of those already existing in the circu- 

 lating fluid, towards the affected spot ; but partly by an actual increase or 

 generation of these bodies, which appear to have the power of very rapidly 

 multiplying themselves. The accumulation of Colourless corpuscles maybe 

 easily seen, by applying irritants to the web of a Frog's foot. Mr. Addison 

 has noticed it in the Human subject, in blood drawn by the prick of a needle 

 from an inflamed pimple, the base of a boil, the skin in scarlatina, &c. And 

 the Author, without any knowledge of these observations, had remarked a 

 very obvious difference between the proportions of Colourless corpuscles, in 

 blood drawn from a wound in the skin of a Frog immediately upon the in- 

 cision being made, and in that drawn a few minutes after ; and had been led, 

 like the observers just quoted, to refer this difference to a determination of 

 Colourless corpuscles to a part irritated. The absolute increase, sometimes 

 to a very considerable amount, in the quantity of Colourless corpuscles in the 

 blood of an inflamed subject, has been verified by Mr. Gulliver and several 



* [Elements of Physiology, translated by R. Willis.] 



Medical Gazette, Dec. 1840; Jan. and March, 1S41. 



J Medical Gazette, July, 1841 ; and Principles of Medicine, [Am. Ed., by Dr. Clymer, pp. 

 214, 215.] 



