8 
Journal of the 
for in a slide of blood treated with prussic acid, the observer may 
perhaps, at first, note a minute oil-like point, and watching it, he 
will find it increase to the size of a rice starch grain and larger, 
and then suddenly assume a decided starchy form, and appear¬ 
ance, and then the above re-action by iodine can be brought out; 
or the observer, after having applied prussic acid to the blood, 
can lay it aside for fifteen or twenty minutes, and then carefully 
apply the iodine test, and he will, by the darkened change of 
colour, readily make out an object which ho may have passed 
over, because of its unusual appearance, and he can then revert 
to the gradual formation of such corpuscle by long and careful 
examination of a slide, and bo rewarded with the view of a starch 
body forming in the plasma, as I have done many a time. 
Similar results can be obtained when the blood is acted upon 
by the cupreate solution.* 
(13.) This formation of starch-like grains resulting from the 
action of chemicals (prussio acid, cupreate of ammonia) is well 
worthy of note; and it is likely the above list may be more 
extended. 
There are other chemical agents which affbct the blood in a 
remarkable manner, but require to he examined more carefully as 
to their action, in order fully to elicit the nature of the changes 
brought about; and it is to this line of observation and experi¬ 
ment I desire to direct attention ; at the same time, I must say 
that experiments made with prussic acid should be first carried 
out and fully recognised before going into any others, as the 
results I have obtained have been the means of conveying to me 
a better mode of experimenting than could be obtained by starting 
first with those substances which have not been so constantly and 
frequently employed by me, and have come into use long after. 
It would take a great deal more space than I can afford to 
go into details regarding the many substances which have been 
experimented with, but I will enumerate the principal ones. 
* Note.—T he action of chloral hydrate on tho blood, induced by injecting it 
subcutaneously, and the further action of formic acid, applied in the same 
way, will exhibit abundance of such bodies; and oven the urine will be found 
to exhibit them; so also these changes can be exhibited in tho urine if freshly 
past, by adding the above reagent to tho secretion while under the microscope. 
