The Structure of Colored Blood-Oorptiscles. 265 



XX Y. — The Structure of Colored Blood-Cor-puscle*. 



BY LOUIS ELSBEKG. 



Read December 16th, 1878. 



The discovery of red corpuscles in the blood was one of the 

 first results of microscopical study, over two hundred years 

 ago. Since that time no other constituent of the body has been 

 more frequently examined. Nevertheless, the structure of 

 colored blood-corpuscles has not heretofore been ascertained. 



I. 



The examination of a small drop of fresh human blood, 

 mixed with a drop of a from 40 per cent, to 50 per cent, sat- 

 urated solution of bichromate of potash, and highly magni- 

 fied, 1 reveals in the course of a few hours the following : 



Perhaps the first thing noticed, is that the colored corpuscles 

 vary in size. 



Having made a number of measurements, 2 I can state that in 

 every person's blood that I have examined, there are some as 

 small as, or smaller than, the - s -^j, and in nearly every person's 

 some as large as, or larger than, the ^^Vr of an inch in diam- 

 eter (i. e., .00655 and .00917 Mm.), with transitional sizes 

 between these. The extremes are sometimes not met with in 



(1) My investigations were made with a 1-12 immersion objective, manufactured by 

 Tolles of Boston, and a No. 12 immersion made by Verick of Paris, either of which, with 

 the eye-piece that was used, magnifies about 1090 times. An exceedingly thin cover having 

 been oiled near the edges, the drop of blood obtained from a pin-prick in the palm of the 

 hand, and transferred on a slide, is mixed with a drop of the solution previously prepared, 

 covered, and without delay placed on the microscope stage By a 50 per cent, saturated 

 solution, I mean a saturated solution diluted with an equal quantity of distilled water : 

 by a 40 per cent., one containing three-fifths water ; by a 60 per cent., one containing two- 

 fifths water, etc : I always prepare a saturated solution, and then dilute. 



(2) I used with the Tolles' lens, and central illumination, in the eye-piece a micrometer- 

 scale ruled with great exactness by Grunow of New York, each division of which was ascer- 

 tained by the Standard Stage Micrometer of Kogers. N. S. No. 3. belonging to Mr. Fred'k 

 Habirshaw, of New York, to measure, with the objective, eye-piece, and cover-adjustment 

 employed, a 1-15,500, and each sub-division a 1-7T.500 part of an inch. 



