SOME OBSERVATIONS ON THE VIRUS OF VACCINIA 
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in tlie incubated préparations is so complicated, that although 
vaccine-like bodies were occasionally observed, they could not 
be differentiated from other non-specific degenerations. 
The Resuit of Incubating the Virus in Varions Media. — 
This work lias been carried on vvith Doctor Grand for the last 
nine months. It may be stated al oiico that in no instance 
hâve we obtained any vesicles following inoculations on the 
shaven skin of a rabbit after the third transfer from the ori¬ 
ginal virus, and in the third transfer only in a very few times. 
The éruption was such as to indicate a graduai weakening 
and dilution of the original virus ratherthan an actual growth. 
With virus purified by oui? methods, we hâve attempted to 
repeat Fornet’s experiments. We hâve used varions viruses 
and made many attempis but always with négative results. 
We find occasionally an uncontaminated virus, when streaked 
on agar plaies and kept anaerobically, will remain active for 
8 weeks at 33°C. although gradually dying out during that 
time. Neither the original plate nor transfers to other media or 
to fresh plates gave any indication of growth of the virus. 
Summary. — A pure active virus of vaccinia can be obtained 
b y repeated partial disinfeclion with carholic acid and glycerin. 
The virus of vaccinia incubated in tissue cultures composed 
of plasma and cornea or testis from normal rabbits or guinea- 
pigs shows a defini te increase, but the degree of multiplication 
is not comparable to that observed in cultures of rapidly 
growing bacteria. The increase of the virus occurs mainly in 
the tissue, but very little in the surrounding plasma. 
The multiplication of the virus occurs without a correspon- 
ding development of vaccine bodies in the préparations. 
There is no growth of the virus in préparations containing 
cornea kilied by freezing or by hypotonie sait solution. 
There is no evidence of the growth of the virus in prépara¬ 
tions in wliicli pièces of paraffin, heart, liver or kidney hâve 
been substituted for the cornea or testis. 
The virus is soon rendered inactive in préparations contain¬ 
ing plasma and cornea obtained from an immune rabbit. The 
greatest lytic action is exerted by the plasma. 
