TRANSACTIONS OF SECTION D. 597 
blood vessels, and are swept onward until they reach the right ventricle of the 
heart, from which they are pumped into the pulmonary circulation. When they 
reach the small vessels surrounding the air vesicles they pass out of the blood 
vessels into the air cavities. 
From the time the larva perforates the skin until it arrives at the lungs it 
remains of the same size, but as soon as it reaches the air vesicles it begins to 
grow rapidly. It then makes its way out of the vesicles into the bronchioles, and, 
travelling up the bronchi and trachea, emerges through the larynx, and by crawling 
over the epiglottis passes into the cesophagus, and from thence into the duodenum. 
5. Cytoryctes variole Guarnieri : the Organism of Small-pox. 
Ly Professor G. N. Caukins, 
In spite of the fact that the organism of small-pox has come to be regarded by 
perhaps the majority of zoologists as an interesting but highly elusive species of 
will-o-the-wisp, I have had the temerity to bring before you still another attempt 
to describe and classify it. 
The present attempt goes back to 1892, when tie Italian pathologist, Guarnieri, 
inoculated a rabbit’s cornea with vaccine virus. Upon studying the tissues thus 
vaccinated he found in the epithelial cells peculiar homogeneous bodies of diverse 
form and size. He then examined skin from human subjects suffering the mild 
disorder, vaccinia, and skin from human subjects with the much more malignant 
disease, small-pox. In both cases he found bodies apparently identical with those 
previously observed in the rabbit. In the subsequent history of these diseases the 
peculiar structures came to be known as the ‘ Guarnieri bodies,’ and’ were usually 
interpreted as degeneration products, although Guarnieri himself regarded them 
as Protozoa, and called the organisms Cytoryctes vaccinie and C. variole re- 
spectively. 
The main reason why pathologists failed to accept Guarnieri's conclusion 
seems to be that bis so-called organisms did not conform in any way with the 
postulates which Koch set up for the determination of bacterial disease germs. 
They had no apparent structure and could not be cultivated on artificial media. 
These objections, to my mind, were quite disposed of by the admirable experi- 
ments of Von Wasielewsky in 1901. He vaccinated a rabbit with a small quantity 
of virus; from this rabbit a second was vaccinated; from the second, a third, 
and so on until forty-seven rabbits were successfully inoculated without using the 
original virus a second time. In all the rabbits, after an appropriate period, 
the same bodies as those described by Guarnieri were found, and in approximately 
the same number as in the originally vaccinated rabbit. This result left only 
one conclusion, viz., that the questionable bodies had undergone growth and 
multiplication, the attributes of a living organism. 
Up to this time the Guarnieri bodies, or Cytoryctes, had been observed only 
in the cytoplasm. In 1902, Councilman of Harvard discovered peculiar and 
definite bodies in the nuclei of skin-cells infected with small-pox. He also found 
the usual cytoplasmic forms, This discovery led him, in April 1903, to publish, 
with Drs. Magrath and Brinckerhof, the hypothesis that Cytoryctes vaccinie 
and C. variole are one and the same organism; further, that the mild disorder, 
vaccinia, is characterised by the cytoplasmic phase alone, while the malignant 
” small-pox, is characterised by the vaccinia phase, plus the intranuclear 
phase. 
I was invited by Dr. Councilman to try to formulate a life history of the 
organism, and his splendid material from fifty-five different cases was generously 
turned over to my use. The results of this study were published this spring. 
To a zoologist confronted by the thousands of bizarre structures which fixed 
and stained small-pox material presents the problem seemed at first to be well- 
nigh hopeless. Added to the difficulties of interpretation from morphology alone 
was the fact that nowhere among the Protozoa are similar organisms known. 
The nearest analogies to the structures observed are in the groups Microsporidia 
