si’ikoch^;tosis of Sudanese fowls 
39 
and no spirilla can be demonstrated in the blood. The guinea pig was found to bo insusceptible, 
and in monkeys only a local cEdema followed inoculation. 
It was shown that fresh serum acted in the same manner as infected blood, that the 
spirilla agglutinate very rapidly in serum, and that after 48 hours all their movements 
cease and the serum ceases to bo infectious. Such serum possesses immunising properties, 
and this power is destroyed in twenty minutes hy a temperature of 55° C. Serum passed 
through a Berkefeld filter loses its virulence, but possesses immunising properties. 
fowl which has recovered from the disease was found to possess an absolute immunity. 
Thus 2 c.c. of blood from a fowl recovered for a period of one month, given 48 hours 
before a virulent injection, wholly protected from infection. There was not even elevation 
of temperature or loss of weight. A second injection only produced a transient effect. 
Preventive serum mixed with virulent serum for five minutes rendered the latter harmless, 
as a general rule. 
2. Levaditi' then took up the subject and obtained rather different results. He found 
the guinea fowl was refractory — showed that the crisis was, properly speaking, a lysis, and that 
death might occur either before or after this lysis. In the inoculated disease he found the 
illness usually lasted four to six days before the lysis occurred. Other points noted by him 
were;— 
(а) Young fowls never show the lysis, but die three to eight days after inoculation. 
(б) In tick infection the incubation period is five to six days 
(c) There is no local multiplication of spirilla— i.e. at site of inoculation. They divide 
transversely. 
(d) The disappearance of the spirilla is not associated with phagocytosis in the peripheral 
blood. This is accomplished by the macrophages of the spleen and liver. Sometimes red 
blood corpuscles or their free nuclei are taken up by the leucocytes. 
(c) A susceptible young fowl inoculated with defibrinated blood, 26 hours after lysis, and 
apparently quite free from spirilla, became infected. This show'ed that spirilla were present, 
though they could not be demonstrated. 
(/) A mono- and sometimes a polynuclear leucocytosis, together with basophilia of 
the erythrocytes, and the presence of large (splenic ?) vacuolated mononuclears in the hlood. 
These increase in numbers before the so-called crisis. 
(fj) The agglutination is not permanent, the spirilla regaining their freedom in from 
4 to 35 minutes. False clumping is probably due to the abrupt change produced when 
the blood is taken for examination. 
(/i) True agglutinins and immobilisines appear after the crisis. 
(f) No granular transformation of spirilla occurs. Levaditi also discussed the cause 
of the crisis and opposed the view of Gabritschewsky,- who, as regards Sp. anserina, believed 
that it was brought about by anti-bodies in the blood. Levaditi upheld the phagocytic 
theory, pointing out that the last spirilla remaining in the circulation are w'holly unchanged, 
and advancing e.xperimental proof to show that his theory regarding the splenic and 
hepatic macrophages fully explained the mechanism. These arguments need not be given 
in detail. 
3. Sakharoff^ had previously discovered a similar disease attacking geese in the 
Caucasus. He named the spirillum Sj). anserina, and found that it was pathogenic for 
' Levaditi, G. (March •25th, 1004), “ Contributions ii I’Etude de la Spirillose des Toules.” Ami. de 
I’Institut Pasteur, Vol. XVIII. 
“ Gabritschewsky, G. Cent. f. Baht., Vol. XXIII., Nos. 0-lS; Vol. XXVI., No.s. 10, 10, 17 ; Vol. XXVII., No. 2. 
■' Sakharolf, G. P. Ann. de I’Institut Pasteur, p. 504, Vol. V. 
The (lue.stion 
of immunity 
Work l>y 
Levaditi 
The disease 
in geese 
