ON THE PREPARATION OF MICROSCOPIC CRYSTALS. 27] 
such a perfectly typical form ; and that gentleman’s explanation was so clear 
that he had induced him to prepare the paper. He was sure they would agree 
with him that Mr. Waddington had shown such great dexterity in preparing 
slides, and in devising processes by which crystals might be obtained in a typical 
form, that no other person could better continue the investigation of this subject. 
They had had some excellent papers from Mr. Deane and Mr. Brady, more 
especially on microscopic analysis as applied to pharmacy ; and he would remark 
that if the microscope was to be of any use at all to the analyst in distinguish¬ 
ing crystallized substances, he must have a certain absolute certainty that the 
crystals he formed were the bodies which he had been told to expect them to be ; 
and that if those crystals were not there, the substance which would produce 
them was absent. They were not in a position to be sure of this, for organic 
substances especially assumed apparently many forms when crystallized from 
liquids containing a great deal of vegetable matter; for instance, uric acid, 
which had been mentioned by Mr. Waddington, assumed many forms ; and he 
might mention also that within the last twenty-four hours he had great difficulty 
in satisfying himself of the presence of cocculus indicus in a material sent to 
him for analysis, because, although he obtained the chemical reactions which 
were supposed to indicate its presence, he could not get the crystalline form 
which he had expected. He obtained it in crystals, but in forms different from 
those in which it usually appeared ; and it was not without a great deal of 
trouble that he did at last obtain that substance in crystals of the distinctive 
form. Many substances crystallized in more than one form when they came 
from salts containing a good deal of vegetable matter, and this subject, there¬ 
fore, might very usefully be treated in a series of papers by such a gentleman 
as Mr. Waddington. 
Professor Bentley desired to express his thanks to the author of the very 
interesting paper they had heard, and which was useful, not only from its in¬ 
trinsic merits, but from bringing before the meeting a subject which was too 
much lost sight of by pharmaceutists,—the application of the microscope to 
pharmacy,—and he hoped they would have many more papers of a similar 
character. 
The President said he felt sure the whole meeting would concur with him 
in asking Mr. Waddington to continue his researches, and give them the 
result. 
Dr. Bedwood had been much struck with one part of the instructions given 
by Mr. Waddington, which was quite opposed to his own experience in prepar¬ 
ing, not microscopic crystals, but crystals generally. It was suggested that crys¬ 
tallization on the slide should be as rapid as possible, but this was not the method 
usually adopted in order to get crystals of large size. He and those who had worked 
with him had been very successful in getting large crystals iu a perfect form, 
but they had always been formed very slowly ; and he should therefore like to 
know what induced Mr. AVaddington to recommend so strongly the contrary 
mode. 
Mr. Waddington said his object had been to get perfect crystals rather than 
large ones, which, perhaps, made a difference. 
Dr. Bedwood said his object had been to get crystals both large and perfect, 
and he had obtained very fine specimens of alums, sulphate of copper, sulphate 
of magnesia, and other salts of that description, but iu each case had adopted a 
very slow process, using solutions only very slightly supersaturated, and allow¬ 
ing the deposition to take place during a period of weeks and even months. 
He had had no experience in preparing microscopic crystals, and would like to 
know why a different process was required in such cases. 
Mr. Waddington said he had been led to adopt the rapid process from 
observing the beauty of the crystals thrown down by hot solutions, and 
