Dr Duckworth, Note on a method of demonstrating, etc. 425 
Note on a method of demonstrating the syncytial appendages 
of the placental villi. By W. L. H. Duckworth, M.D., Sc.D., 
Jesus College, University Lecturer in Physical Anthropology. 
[. Received 3 February 1908.] 
[Plate XIV.] 
The human placenta of the later stages of pregnancy (6th or 
7th months) provides material for a very rapid and effective 
method of demonstrating the appearance of syncytial masses of 
protoplasm. I have found the material and the method specially 
useful in making preparations for a number of students. 
Wishing to exhibit the connexions of the syncytial outgrowths 
from the villi, with the parent stems, more clearly than is the 
case in sections of the placenta, I tried the effect of teazing the 
tissue. At first I did not realise how easily the villi can be 
teazed out, and therefore having removed a small block (a cube 
of about 5 mm.) from the uterine surface of a well-preserved 
formalin-fixed (6th month) placenta, I placed the tissue in strong 
nitric acid, so as to facilitate teazing. I found that with properly 
fixed material of this sort, very strong nitric acid can be used, 
so that even 25 °/ 0 of pure nitric acid with distilled water does 
not impair the histological features of the villi. The mixture of 
phloroglucin with nitric acid (cf. Bolles Lee’s Microtomists Vade- 
Mecum (Haug’s Method) p. 314, Ed. 6), gives very good results. 
After a somewhat prolonged immersion (3 days) in the acid, the 
block was well washed, and small fragments were stained in 
Delafield’s Haematoxylin. This stain acts very rapidly, and with 
the smaller pieces the period of immersion in the staining fluid 
must be reduced to \ minute. After dehydrating and clearing, 
by any of the ordinary methods, the small fragments of the block 
were teazed out on slides, and mounted in Canada Balsam. The 
nuclei of the syncytial masses are stained intensely, and the con- 
nexions of these outgrowths with the villi are very strikingly 
displayed when the specimen is examined with a objective 
and ocular No. 2 or No. 3. Very beautiful specimens are also 
obtained (after the preliminary immersion in acid) by staining 
larger blocks for a longer period (10 days) in borax carmine or 
in a 10 °/ 0 solution of Griibler’s haemalum. 
Subsequently I found that for class-work, the preliminary 
treatment with acid is unnecessary, so that the preparation of 
specimens stained with haematoxylin is very rapid and easy. 
In examining specimens prepared in these ways, I have been 
