72 Transactions of the Boyal Microsco^pical Society, 
and rendering the remaining contents in the interior of the nucleus 
granular ; while the darkness of the double contour of the nucleus 
itself is caused by an increase in density of the wall, which it 
represents. 
'When the coloured blood-corpuscles of the Amphiuma are 
treated with a weak solution of chromic acid, and the action of the 
reagent continues, they are rendered colourless. At the same time, 
they are bordered by a distinct double contour, and their proto- 
plasm appears finely granular. The nucleus also is distinguished 
by a dark double contour and by granular contents. Finally, if 
the action still continues, the granular contents of the corpuscle 
are dissolved, and the latter appears as a clear cell with a double 
contour. 
Concerning the action of a weak solution of chromic acid upon 
these blood-corpuscles, I have made an interesting observation. 
"When a fresh specimen of the blood of Amphiuma is treated with 
water under the microscope, and subsequently, after the coloured 
blood-corpuscles have become discoloured and rendered very pale 
by the action of the water, and a very weak solution of chromic 
acid is added, the following changes will be observed to take place in 
a number of the corpuscles : becoming almost invisible, they will re- 
appear, bordered by decided dark double contours, while their nuclei, 
also distinguished by dark double contours and granular contents, 
are coloured yellow from the reagent. But the most interesting part 
of the phenomenon is a series of fine lines, radiating from the peri- 
phery of the nucleus through the protoplasm to the inner surface 
of the membraneous layer of the blood-corpuscle (Fig. 24). Now 
this picture would almost seem to corroborate the theory of Hensen, 
as well as that of Kollmann ; the fine double lines representing the 
filaments, which they suppose to radiate from the nucleus to the 
enveloping membrane. But this is not the case. For a closer 
examination reveals that these lines represent nothing but fissures 
in the protoplasm, which appears to have assumed some form of 
crystallization. This becomes more evident by observing some of 
these fissures, deviating from their course and giving rise to sub- 
ordinate branches, as is seen in Fig. 24. 
AVhat this colourless crystallizable constituent of the protoplasm, 
manifesting itself by the above-described reaction with a weak 
solution of chromic acid, may be, I must leave to the organic 
chemist to decide. It will be remembered, however, that a number 
of years ago Lehmann succeeded in discolouring the original blood- 
crystals, demonstrating the albuminous body in its crystalline 
form,* though Kuehne, who regards the coloured blood-corpuscles 
as consisting of a certain stroma, in the interstices of which the 
haemoglobin was to he contained, subsequently declared this 
* O. Funke, ‘ Lehrbuch der Pliysiologie,’ 4th edit., vol. i. p. 40. 
