N. H. SWELLENGREBEL 
453 
and that it only seldom can be observed in a living •condition. The 
sphere never stains with eosin. I cannot confirm Chatton and Lalung 
Bonaire’s view on this subject. After being coloured by eosin, dark 
staining granules may be observed in the plasmatic fringe, no cyst-wall 
was observed to surround the cell, consequently Blastocystis is not a cyst. 
With the object of determining whether Blastocystis is a normal 
developmental form of Trichomonas or Chilomastix the following experi¬ 
ments were undertaken: 
Case No. 1. European, having resided in the Dutch Indies for 
some years, returned October 1913. The stools contain Limax amoebae. 
Entamoeba coli and Blastocystis, they were regularly observed for several 
months, but no other parasites were found. After the administration 
of four cascara tabloids, many blastocysts were present in the semi- 
flmd stools; after strong purgation (30 grams of sulphate of magnesia) 
the stools became fluid but no flagellates of any kind were found. 
A diet consisting of milk and some eggs only caused the blastocysts 
to diminish in number but not to disappear. 
Case No. 2. Javanese, temporarily residing in Europe. In the 
stools Limax amoebae and Blastocystis were present, and observation 
of three months’ duration did not reveal any other parasites. Purga¬ 
tion with sulphate of magnesia (15 grams) did not cause the appearance 
of flagellates. 
These experiments show that Blastocystis may be continually pre¬ 
sent in the intestine without any traces of flagellates being found even 
after prolonged observation. Although in other cases I found Blasto- 
cystis together with Chilomastix mesnili, the former observations show 
that even if blastocysts can be formed from Chilomastix they also may 
be formed without the help of this flagellate. 
3. Observation on fixed and stained preparations. 
Wet-fixed (corrosive alcohol) preparations were stained with iron- 
or Delafield’s haematoxyUn. The results obtained from these observa¬ 
tions will be recorded for each case separately : 
Case No. 2 (PI. XVI, Figs. 1-27). 
{For particulars of this case see above.) 
With iron-haematoxylin, the sphere stained yellowish-grey (Figs. 14- 
19). The surrounding cytoplasm stained a pale grey, it showed an 
alveolar structure (Figs. 14, 15, 17) or no structure at all (Fig. 16), 
30—2 
