about i^/q, and it therefore answers all the requirements of such a 
quantitative method of estimation. 
In the course of our experiments we found it a very suitable plan 
to dissolve the oil in lo cc. alcohol of 95 to 96^/0 by volume, before 
the water is added. By these means the oil can be divided so min- 
utely, that the aqueous solution in most cases only has a cloudy opal- 
escence, which naturally removes the danger which threatens under 
ordinary circumstances, namely that the unattacked cinnamic aldehyde 
may be enveloped by the semi-oxamazone. Under these conditions 
the precipitate could also in every case be filtered off rapidly, and 
the results obtained were excellent, so that we can strongly recommend 
this slight modification. 
Hanus' method will be particularly advantageous wherever it is a 
question of only a small quantity of cinnamon oil, or of a specially 
exact determination of the aldehyde-content; but for ordinary practice 
it may be recommended to retain the easier and more readily applied 
bisulphite method, the more so, as with pure cinnamic aldehyde and 
cassia oil the results are very satisfactory, — a fact which we were again 
able to confirm on the occasion of the present experiments. 
In the case of the Ceylon cinnamon oils the difference in the results 
obtained by the two methods was rather considerable (up to 
this is also clear from the examples mentioned in Hanus' work. This 
difference is very probably due to the presence of the other aldehydes 
contained in the Ceylon oil. When the percentages by volume obtained 
by the bisulphite method are converted into percentages by weight the 
values increase no doubt by 2 ^/q, but in spite of this they still remain 
4 to below the values according to Hanus. 
But the method indicated by Hanus has a further special value, 
inasmuch as it enables us to ascertain in a convenient manner the 
aldehyde- content of a cinnamon bark, which up to now was only possible 
by means of a trial -distillation, and which consequently often gave 
rise to difficulties. 
For this determination, which he has also tested thoroughly as to its 
usefulness, Hanus gives the following directions: In a large Erlen- 
meyer flask 5 to 8 grams of finely ground cinnamon are weighed off, 
and loocc. water added. The flask is then closed by means of a rubber 
stopper with two holes, through which pass a thin glass tube drawn 
out at the lower end, which serves for admission of the steam, and 
which reaches almost to the bottom of the flask, and a second shorter 
tube, bent in the shape of a knee, which forms the connection between 
the flask and a Liebig's condenser. First of all the flask with the 
cinnamon is heated to boiling temperature, and only then a powerful 
stream of water vapour admitted. At this point attention should be 
paid that the steam admission tube does not become choked up at 
