THE AUSTRALASIAN JOURNAL OF PHARMACY. 
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in analysis. The writer would lay special stress upon the importance of acquiring 
real skill and accuracy in the detection of chemical bodies by becoming familiar, 
not only with ordinary stereotyped tests, but also with the respective merits of 
the various means of their recognition as regards both delicacy and speed. 
Up till about nine years ago the knowledge of candidates in the subject of 
Practical Chemistry in the test examinations for teachers instituted by the Science 
and Art Department of the Privy Council on Education in England was judged 
by answers to questions set on paper ; but the results proved highly unsatisfactory, 
for many candidates passed the ordeal who were signally ignorant of even the 
simplest methods of analytical investigation. A separate practical examination 
was, therefore, established, and certificates are granted for the practical as 
well as the theoretical branch of the science. It is easy to conceive that a 
cram-student might learn by rote the columns of a “ separation chart ” without 
any experience in laboratory practice ; and many such have escaped the meshes 
of the Government examiner’s net. 
But even when practical experience is resorted to, many troubles arise to 
the beginner unless he has constant attention and guidance from some 
supervisor — one who will not perform the operations for the student, but show 
him how to do the work himself. One cannot always foresee the difficulties 
that may be encountered in the identification of the metals, or other chemicals, 
or in the detection of impurities ; but there are many common stumbling-blocks 
met with by the average student against which hints from an experienced hand 
may serve as warning finger-posts, whether in letter-press or viva voce. It 
requires, however, a great deal of patience, perseverance, method, and instruction 
to overcome all the perplexities that may crop up in analytical investigation. 
Extensive works on analysis like those of Fresenius are full of notes 
explanatory of such pitfalls, but, as a rule, they are so elaborate 
as to receive but cursory attention from the tyro, and he is likely to 
commit greater blunders than ever. The moral is that the student should not 
hurry over his work, but take every possible pains to master one group until he 
feels quite competent to asseverate what individual members are present. Having 
accomplished this, he may then direct his attention to the succeeding groups in 
the same methodical fashion. Yet it should be remembered that the presence of 
one set of bases, or of the re-agents added to separate them, may interfere with 
the detection or removal of some others — e.g ., it would be quite out of place to 
look for ammonia in a solution after having got rid of the iron group, since 
certain compounds of that base have to be added in the ordinary test processes. 
Ammonia must always be looked for in the original substance or solution by a 
direct test. But it does not follow, as novices seem to think, that the original 
solution can be examined in a similar manner for other bases. If sulphurous 
acid is used to reduce arseniates to ensure complete precipitation of arsenicum, 
as sulphide (by the passage of a stream of sulphuretted hydrogen gas), 
sulphuric acid is necessarily formed by oxidation of the lower acid. It will 
therefore throw down barium (if that base be present), as insoluble sulphate, and 
the latter may be lost sight of in its proper place in consequence. Again, if 
that reduction is not performed, sulphuretted hydrogen will not precipitate the 
arsenic, and the student may think he has phosphates present when he comes to 
apply the molybdate test, and again fall into embarrassing complications, besides 
losing time over the special treatment. Once more, ferric chloride is reduced to 
ferrous chloride by the passage of SH 2 to remove the metals of group ii., and 
then the iron will not be thoroughly precipitated by ammonia in the ensuing 
group unless the precaution be taken beforehand to oxidize it by boiling with a 
few drops of nitric acid. 
