?422 APPENDIX TO REPORT OF THE LEPROSY COMMISSION:
as that described by Neisser, we shall speak of as the vacuolated
bacillus In a later paper Neisser,31 as the result of extended obser-
vations, inclines to the view that the vacuoles, or spaces in the
bacillus, are veritable spores, though in no instance has he seen an
isolated spore. The ball-like swelling in the second kind he does not
regard as a spore-formation. He also confirms the presence of the
hull of the bacillus, stating that it can easily be seen after staining a
preparation with watery dye. The presence of this hull is botanically
of interest; it occurs also in the Bacillus Tuberculosis,32 Pneumococ-
cus,33 and several other forms.
Further culture experiments by Neisser consisted in using solid
blood serum and hard-boiled fowl or duck eggs as a nutrient medium,
and minute pieces of excised tubercle, or blood from a tubercle, as
material for inoculation. The culture was maintained at a tempera-
ture of 37°-38°C. The growth was exceedingly slow. Cultivation
in generations was not successful. Specimens from detached bacillary
islets on the medium yielded what the author held to be a genuine
cultivation of the Bacillus Leprę.
Hansen 34 in 1882 described a culture on serum of bacilli which
were motile. He used methylene-blue as a stain, but according to
Neisser this will not even tinge the genuine Bacillus Leprę. This is
not a strong argument against Hansen's culture, for in our hands
methyl-blue stains the Bacillus Leprę, though great differences exist
in the samples of this dye, so that the discordant results of various
observers are conceivable.
It is impossible to be quite certain that a veritable cultivation of
the Bacillus Leprę was obtained by Neisser. On Plate XII,34 Figs.
1, 5, 6, and especially 10, have the appearance of true cultures, but
when it is considered that this observer wholly failed to cultivate the
bacillus in generations, an actual multiplication in fluids which pro-
bably did occur is all that can be conceded.
Manson,35 some years before Hansen had discovered the Bacillus
Leprę, attempted by incubation of leper juice to discover the then
unknown germ. Sealed capillary tubes were inserted into eggs which
were placed under a hen. Beyond the development of streptococci,
both free and in the zooglœa state, these experiments gave wholly
negative results.
(31) Virchow's Archiv. 1886.
(32) Lutz and Unna. Dermatol. Studien Heft I. 1886.
(33) Friedländer. Fortschr. d. Med. Bd. III, 1885.
(34) Virchow's Archiv. 1881.
(35) Journal of the Leprosy Investigation Committee, No. 1, p. 40.