28 
PROGRESS OF MICROSCOPICAL SCIENCE. 
and flinty felstone-like roclc, undistinguisliable in Land specimens 
from a true contemporaneous trap. Suck altered rocks were, how- 
ever, quite distinct in microscopic structure from the undoubted 
lava-flows of the same district, and often distinct also from the 
Welsh felstones, although some were almost identical microscopically 
with the highly altered ashes of Wales, and together with them 
resembled the felstone-lavas of the same country. 
The author believed that one other truth of no slight importance 
might be gathered from these investigations, viz. that neither the 
careful inspection of hand-specimens, nor the microscopic examination 
of thin slices, would in all cases enable truthful results to be arrived 
at, in discriminating between trap and altered ash-rocks ; but these 
methods and that of chemical analysis must be accompanied by often- 
times a laborious and detailed survey of the rocks in the open country, 
the various beds being traced out one by one and their weathered 
surfaces particularly noticed. A very interesting discussion followed 
the perusal of the paper. 
The Pathology of the Blood. — M. Laptscliinsky, of St. Peters- 
burg, contributes a paper to the £ Centralblatt,’ on the microscopic 
changes undergone by the blood in various diseases, which is thus 
given in the ‘ Lancet,’ October 31. He finds that in various diseases 
in which marked febrile symptoms are present, the microscopic aspect 
of the blood is essentially different from that of health. The changes 
consist in the blood-corpuscles not running into regularly formed 
rouleaux, but accumulating in heaps or clumps of various size and 
shape. The individual blood-corpuscles frequently appear swollen 
and cloudy, and their contours less distinct than natural. Small 
corpuscles, one-third of the normal size, are often met with, some of 
which exhibit a more intense colour than natural, whilst others are 
completely pale. In the interspaces of the clumps of red corpuscles, 
great numbers of white corpuscles may be seen, often coalescing to 
form groups of from 3 to 8. In typhus he counted from 60 to 80, 
and more, in one field of vision; in cholera from 110 to 130. Careful 
enumeration of the relative numbers of white and red corpuscles four 
days after death in the above cases showed that there was 1 white to 
60 red corpuscles in the case of typhus, and 1 white to 23 coloured 
in the case of cholera. In a very anaemic woman, suffering from 
suppuration in the knee-joint, the proportion of the white rose to 1 to 
13 red. The white corpuscles in these cases presented unusually 
active and extensive amoeboid movements. The nuclei of the colour- 
less corpuscles took a part in the amoeboid movements, and could be 
seen altering their position and form in the interior of the white 
corpuscles. The thorn-apple or horse-chestnut like form of the red 
corpuscles he did not find to be unusually frequent. He found, how- 
ever, large quantities of granular or detritus-like material in the 
blood of febrile, but not much in the blood of cachectic and anaemic 
patients. From his enumerations he feels satisfied that in febrile 
diseases, and in Bright’s disease, the conversion or development of 
white corpuscles into red is either materially retarded or is entirely 
arrested. 
