S. GANAPATHY IYER                                                    23

                                                TABLE V—contd

Vaccine
lot No.

Date of
inoculation

Fowl
No.

Inoculum 5 c. c.
subcut

Result of
Vaccination

Result of immunity
test

III

2 May 1940 .

2273

Passage 33 . .

Remained well

Contact infection on 16 May
1940 and 100 million M. L.
D. on 7 June 1940, immune

2274

2275

2276

Do . .

Do . .

7th day inoculated fowl virus,
died 4th day

2278

Do . .

Do . .

14th day inoculated fowl
virus, immune

2277

Do . .

Do . .

21st day inoculated fowl virus,
immune

2279

Control egg virus
plus saline

Do . .

14th day inoculated fowl virus,
immune

2287

Left in contact with
the vaccinated
fowls inside pen

Do . .

14th day contact infection,
died 6th day, whereas none
of the vaccinated fowls
exposed to similar infection
died

(iii) Formalized egg virus

Experiment I. Newcastle virus cultivated through 12 generations in
eggs was used. To a one per cent suspension of infected embryo in phosphate
buffer, pH 7.6, formalin was added to a concentration of 0.2 per cent and
the mixture was attenuated at 37°C. for 72 hours. Inoculations were made
as follows:—

                                          TABLE VI

                                    Formalized egg virus

Date
of
inoculation

Fowl
No.

Dose
and
route

Result and remarks

5-2-40

2139

5 c.c. S/c

Survived, tested immunity 28 February 1940,
died 4 March 1940

5-2-40

2138

„

Control, virus and saline kept 37°C. 72 hours, died
4th day.

There was no protection following inoculation with formalized egg virus.
Formalin had rendered the virus inert, for the control fowl died of Newcastle
disease ; the virus was, therefore, fully virulent even after incubation at 37°C.,
for 72 hours. It may be recalled here that Beard, Finkelstein, Sealy and
Wyckoff [1938] obtained favourable results in the process of vaccination
against equine encephalomyelitis with formalized vaccine using virus pro-
pagated through eggs. In the preliminary experiment for Newcastle dis-
ease detailed above, similar results could not be obtained (Table VI).

Experiment II. Another sample of formalized vaccine from egg virus
after having undergone 27 passages was prepared and tested in fowls. In
this case, 10 per cent tissue emulsion was used and the concentration of forma-
lin was 0.4 per cent and the mixture attenuated 48 hours at 37°C. (Table VII)