198 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
sites of the haematoblasts — and the biological and morphological modifi- 
cations of this variety are dependent on the character of the host-cell, 
or in other words, on the stage of development of the baematoblasts at the 
moment of infection. Placing them in series, these varieties; or rather 
modifications of a variety, become (1) Hsmamsba immaculata ; (2) H. febris 
quotidians ; (3) H. f. tertians maligns ; (4) crescents of acute perni- 
cious fever ; (5) ordinary crescents. The crescents are nothing else 
than the parasites of the younger stage of the hsematoblasts, while the 
other parasites of the irregular forms have infected the liaematoblasts at 
later stages of development. The author’s theory is supported by facts 
derived from observations on birds, and he infers that similar pheno- 
mena must occur in man, although he admits that he has never seen a 
parasite in a nucleated erythrocyte from a case of pernicious fever. The 
explanation of this discrepancy is to be sought in the escape of the 
nucleus, when the parasite enters the hsematoblast. When the nucleus 
has escaped, protoplasm of the transitional erythrocyte can no longer be 
distinguished from that of the fully formed erythrocyte. 
Amcebse Cultivated on Solid Media.* — Dr. M. W. Beyerinck gives 
the life-history of two amoebae which were successfully cultivated on 
solid media. Amsba nitropbila was obtained from garden earth, and 
cultivated on media used for nitrifying bacteria. When fully formed it 
measures 15-20 p ; the sarcode is hyaline, and there is a well-marked 
nucleus. There are two vacuoles, one of which is contractile. There 
are often three accessory vacuoles in connection with the last. Multi- 
plication by fission was easily observed. Spore-formation somewhat 
analogous to that in Myxomycetes took place. The spore-wall is double. 
When the young amoeba (10-12 p) escapes from the spore-case the 
hyaline protoplasm goes first, then follows the vacuole, and directly 
behind the nucleus. 
Amsba zymophila was isolated from grapes in company with several 
organisms, the most noteworthy being Saccharomyces apiculatus, and an 
acetic acid bacterium. Cultivated on malt extract gelatin, the medium 
was liquefied. This peptonising effect was ascribed to the presence of 
a tryptic ferment excreted from the vacuole. The liquefaction of the 
medium apparently had no reference to nutrition, for the amoebae took 
solid food. The amoebae measured 10—12 p, and multiplied by fission. 
Neither spore nor cyst formation was observed. The structure of the 
protoplasm appeared to be reticular or foaming. There were two to four 
vacuoles, but none contracted. 
Cultivation of Parasitic Protozoa from Malignant Tumours, &c.| 
Messrs. S. G. Shattock and C. A. Ballance made numerous attempts to 
cultivate parasitic protozoa from malignant tumours, vaccinia, Molluscum 
contagiosum, and from normal tissues, but failed to obtain positive results. 
No traces of protozoic life, whether as spores or amoebaB, were encoun- 
tered, although the examinations were made at regular intervals, and 
repeated for periods of many months. The chief interest of the authors’ 
researches lies in their method of procedure, and the care taken to avoid 
all sources of contamination. 
* Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., xix. (1896) pp. 257-87 (1 pi.). 
t Proc. Roy. Soc., lviii. (1895) pp. 469-72. 
