406 ABSTRACTS
Preliminary note on the growth of Trypanosoma equiperdum in the
developing chick embryo. C. A. MITCHELL, R. V. L. WALKER, HEATH AND
D. G. McKERCHER (1939). Canad. J. Comp. Med. 3, 223-224.
Cultivation of various species of trypanosomes in the developing chick
embryo. B. J. LONGLEY, N. M. CLAUSEN AND A. L. TATUM (1939). Proc.
Soc. Exp. Biol. & Med. 41, 365-366.
A TTEMPTS have repeatedly been made to cultivate these parasites upon artificial
media but without success until very recently. The successful employment of deve-
loping chick embryos for this purpose is therefore of considerable interest, and this may
lead to the elucidation of some obscure points regarding the life-histories of trypanosomes.
Mitchell et al. employed chick embryos at their 12th and 16th days of development.
When infected rats showed teeming numbers of trypanosomes, their heart blood was
collected, and immediately diluted with ten volumes of water. 0.1 c.c. of this diluted
blood was placed on the chorio-allantoic membrane, and the eggs were kept under
observation till they batched in the usual way on the 21st day. The chicks appeared
normal and no trypanosomes were detected in their blood smears. Chick embryos
infected early died in the shell, and their blood was infective to laboratory animals, though
no trypanosomes were demonstrated microscopically. When infected late in embryonic
life, the chicks hatched out normally, appeared to remain healthy till the 3rd day after
hatching when they became drowsy and showed the presence of trypanosomes. Two
days later the chicks died, and the presence of trypanosomes in their blood was revealed
microscopically and by the biological test in rats and guinea-pigs, but adult fowls were
not infected.
Longley and coworkers attempted to correct the arsenic fastness of a strain of T.
rhodesiense by repeated passage through various mammalian hosts. Having failed in
this, cultivation in eggs already incubated for 8-10 days was tried. Infective rat blood
was diluted with normal saline, and 0.5 c.c. of this was introduced aseptically into eggs.
The embryos died in 4-5 days as a result of a heavy trypanosome infection, and the
subinoculations into fresh incubated eggs were carried out every 5th day. The trypano¬
some strain was thus maintained in developing chick embryos for 8 generations lasting
over 41 days. Its virulence and drug fastness remained unchanged over this period. T.
equiperdum, T. brucci, T. evansi, and T. hippicum were also successfully cultivated but
T. lewisi did not produce any satisfactory cultures. The trypanosome strains tested
were not infective to the hatched chicks. [S. C. A. D.]
Chronic fluorine intoxication in domestic animals. A. W. PEIRCE (1939).
Nutrition Abstracts & Reviews 9, 253-261.
T HE subject has been reviewed with reference to (a) the occurrence of fluorosis under
natural conditions, (b) the experimental production of the disease in animals with
a view to elucidate questions arising from clinical observations and (c) the comparative
toxicity of different compounds to various animals. Most of the literature on the sub-
ject, of which the author cites 122 references, refers to the symptomatology of the malady,
part of it to the physiological effects of the disease and a part to the quantitative aspects
of requirement and disease production.
Live volcanic regions and chemical factory tracts using fluorine compounds have
been incriminated as contributing to the contamination of the atmosphere, vegetation
and water supply of the neighbourhood. Chronic fluorine intoxication seems to be
prevalent in North and South America and parts of Europe and Africa, both among
humans and among cattle. Cases among cattle are not usually found in Australia or
Asia, although human cases occur in India, China and Japan.
Among the recorded clinical symptoms are the impairment of gait, difficulty of
locomotion, raggedness of coat, reduction of milk yield and egg production, anaemia,
conjunctival irritation, abnormal skeletal development by way of swollen joints, exos-
toses of the long bone and jaws, spontaneous fractures, selective abrasion of the molars
thickening of the mandible, mottling of the enamel of teeth, change of colour, size,
orientation, shape and structure of the teeth, pitting of the incisors, etc. All these