ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
83 
in milk, and on potato. The optimum temperature was about 20° C. The 
formation of pigment was found to depend on the influence of light ; for, 
although there was no diminution in the energy of growth, yet when the 
cultivations were kept in the dark they remained quite white. No ex- 
periments were made on the formation of pigment with different kinds 
of artificial light, nor any examination of the chemical properties of the 
pigment. 
Disease of the Nun (Liparis monacha).* — Herr C. von Tubeuf 
records some observations made in the Bavarian woodlands during 1890 
and 1891 on diseases affecting the Nun ( Liparis monacha). One of these, 
a kind of lethargy, eventually fatal, is caused and spread by bacteria. 
It is a malady of the digestive system, fostered by definite climatic- 
conditions. The caterpillars ceased to eat, became flaccid, their head 
and body drooped, and they hung on by a few pairs of feet only. The 
skin becomes partially filled out with a brown oily fluid, from which 
the malady might be designated the fat disease. In this fluid all sorts 
of bacteria, which eventually destroy the caterpillar, are found. The 
sick nuns collect in thick masses at the tops of the pine trees, where 
they become torpid and die — a phenomenon known as the “ topping 
of the nuns.” At the same time many caterpillars may be seen in a 
lethargic state on the trunks. The blood and intestinal contents of 
sick caterpillars were examined, and especially that of the foregut, which 
was ejected during the irritative stage. When healthy, this was green and 
composed of fragments of leaves with some bacteria, but in the sickly 
caterpillar it became brown with masses of bacteria. From cultiva- 
tions, a mobile bacterium {Bad. monachse) 1 /x long and 0 * 5 fx broad 
was obtained : this usually was in pairs or chains. The colonies did 
not liquefy gelatiD. In colour like mother-of-pearl or opal with yel- 
lowish centre, the colonies present a characteristic lobate appearance 
which becomes more marked with age. Bac. monachse is strongly 
aerobic. Healthy nun caterpillars were infected by feeding them on 
leaves which had been sprinkled with w T ater containing this bacterium, 
while the caterpillars of other butterflies were unaffected. Usually 
the disorder is very chronic, and when acute is the result of cold wet 
weather, when, owing to the caterpillars having little to eat, the 
Schizomycetes are enabled to multiply in the foregut rather than in the 
solid contents of the after-gut. 
New Chemical Function of the Cholera Bacillus.| — M. J. Ferran 
has found that by cultivating the cholera vibrio in slightly alkaline 
bouillon containing lactose, paralactic acid is produced in quantity suf- 
ficient to impart to the medium a distinctly acid reaction, and if it be 
coloured with litmus the medium turns red. A cultivation made in 
slightly alkaline bouillon to which lactose has been added, and kept at 
30° C. for five days, presents a scum composed of large bacilli, in the 
interior of which highly refracting bodies resembling spores can be 
seen ; finally all the protoplasmic contents disappear, and these little 
bodies, which stain very well with methyl-violet, are set free. 
* Forstlich-naturwiss. Zeitschr., i. (1892) pp. 34-47, 62-79 (4 pi.). See Cen- 
tralbl. f. Bakteriol. u. Parasitenk., xii. (1S92) pp. 268-9. 
t Comptes Kendus, cxv. (1892) pp. 391-2. 
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