128 ROLLESTON, ON NUCLEATION OF BLOOD-CELLS. 
and the camel, possessed nucleated blood-corpuscles. And 
this coincidence determined me to use such means as we had 
at our disposal for settling a point as to which all recent 
authorities were, as far as my knowledge went, opposed to 
Dr. Kiihne. 
The employment of a twelfth-of-an-inch object-glass by the 
same makers has convinced Mr. Moseley and myself that, 
though a certain number of the dried blood-corpuscles of the 
sloth do contain one or more nuclei more or less roughly hewn, 
and irregularly and eccentrically placed, still the immense 
majority of them possess the non-nucleated character ordina- 
rily assigned to the mammalian red blood-cell. The large 
size of the blood-cells of the two-toed sloth, the largest next 
to those of the elephant put on record amongst mammalian 
blood-cells by * Mr. Gulliver, may, in more ways than one, 
have rendered an examination of them by a low power 
amenable to fallacy, and recourse to those of a higher power 
necessary. In the smaller corpuscles of the camel neither 
power enabled us to detect the presence of nuclei in the 
coloured blood-cells. 
Bearing in mind Nasse’s observation + as to the compa- 
rative frequency of the presence of a large colourless nucleus, 
or, in the place of it, of an area of fainter coloration, in the 
coloured blood-cells of the pregnant human subject, and 
also of the pregnant bitch, I examined the blood from the 
uterine veins of a cow which had been killed, in ignorance, 
as I was told, towards the end of the period of gestation. But 
I was unable to discover any nucleated red corpuscles in the 
blood from this source. 
It is well known that nucleated red blood-cells have been 
observed in the blood of the human subject,t of the horse,§ 
of the elephant,|| of the paco,§ and of the sheep ;** but it 
should also be recollected that round coloured blood-cells, so 
“ Gewiss ist es héchst auffallend dass nur das Blut der Saugethiere sich 
durch den Mangel dieses Bestandtheils (des Kerns) auszeichnet, dass nur 
einzelne (Kameel, Faulthier) unter ihnen ‘kernhaltige Blutkorperchen 
besitzen.” 
* Hewson’s Works, p.238. 
+ Wagner’s ‘ Handworterbuch,’ i, 90, cit. M.-Edwards, ‘Legons,’ i, 
. 66. 
; + Nasse, 1. c.; Busk, ‘Quart. Journ. Mic. Soc.,’ 1852; translation of 
Kdlliker’s ‘ Handbook,’ ii, p. 348, 1854. 
§ Wharton Jones, ‘ Phil. Trans.’ for 1846, p. 73. 
|| Ibid., and Schulze, ‘ Muller’s Archiv,’ 1839, p. 252; but see Cotti, 
‘Zeitschrift fir Wiss. Zool.,’ vol. v, cit. Kolliker, ‘Mikro. Anat.,’ ii, 2 
583. 
§ Wharton Jones, 1. c. 
‘** Thid. 
d 
oe 
elie ie 
se ee ee ee 
