94 
AN IRON-HAEMATEIN STAIN. 
WITH REMARKS ON THE GIEMSA STAIN. 
By HARALD SEIDELTN, M.D. 
{From the Lister Institute, Zoological Department.) 
Plate V. 
For geueral purposes, especially in haematological work, the Gieinsa 
method, based on the Romanowsky princijjle, is certainly the most 
satisfactory stain for Protozoa. For certain structures, however, and in 
general as a control of the Giemsa stain, it is always necessary to have 
at one’s disposal another method which will give particularly clear 
pictures of the nuclear elements (see e.g. Minchin, 1909). Of the 
different methods which are employed for this object the iron- 
haematoxylin stain is probably the most valuable and the most 
frequently used. There are, however, several circumstances which are 
unfavourable to its use as a universal stain. Its principal dis¬ 
advantage is, that a differentiation is essential: the preparation is 
first deeply over-stained and the colour is afterwards extracted to the 
degree which is deemed convenient in each particular case. This 
extraction is always somewhat irregular, so that the observation, 
especially of intra-corpuscular parasites, is sometimes made very 
difficult, and it is not often possible to obtain in a single specimen 
a satisfactory stain of all the different elements. This difficulty is 
enhanced by the fact, that the red blood-corpuscles generally retain 
a deep grey, or almost black, colour. Further, a rather serious draw¬ 
back is that in sections where greater masses of blood, and particularly 
blood-clots, are present, it is almost impossible to distinguish either 
intra- or extra-corpuscular parasites; to make such masses of blood 
