ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
223 
Sun Disinfection.* * * § ' — It is well known, says Herr von Esmarch, that 
sunlight is a powerful disinfectant, being able to destroy micro- 
organisms when occurring in thin layers. Experiments with the view 
of rendering this power useful in practice were made with substances 
infected with diphtheria, cholera, typhoid, and suppuration bacteria. 
The results did not answer the expectation ; for though the uppermost 
layers were disinfected, the micro-organisms in the undermost layers 
retained their vitality. For practical purposes, therefore, sunlight is 
not an effective disinfectant. 
Non-Bacterial Nutrition.! — Prof. Duclaux, in discussing the ques- 
tion of non-bacterial nutrition, gives special attention to the recent experi- 
ments of Nuttall and Thierfelder. J Ten years ago the author published 
a note “on germination in soil rich in organic matter but devoid of 
microbes,” and showed that when leguminous plants are grown in a 
medium containing milk, starch, and sugar, the sugar is not inverted 
nor the starch saccharised, nor the milk clotted ; and with regard to 
animals, the position taken up was that while bacteria play a part in 
digestion which cannot be neglected, yet their presence is not a physio- 
logical necessity. M. Pasteur, however, was of opinion that life devoid 
of microbes was an impossibility ; that without their ferment action and 
their peptonising function there could be but imperfect and indifferent 
digestion. Nencki, taking the opposite view, held that bacterial products 
(indol, scatol, ammonia, and such like) were of no nutritive value. For 
the solution of the problem it had been Pasteur’s suggestion that fowls 
should be bred from sterilised eggs, kept in a sterilised atmosphere, and 
fed on sterilised food. MM. Nuttall and Thierfelder, however, found 
that most eggs contain microbes ; their experiments were conducted on 
guinea-pigs. The animals were removed from their mothers by caesarian 
section performed with antiseptic precautions, and were afterwards kept 
in a sterile environment and fed on sterilised food. For the details of 
the laborious and lengthy experiments the original should be consulted. 
It will be sufficient to say that all the difficulties were surmounted, and 
the guinea-pig, which was even in a more thriving condition than its 
brothers and sisters brought up in the ordinary way as checks, was 
opened on the eighth day. No bacteria were found in the alimentary 
canal, all the tubes remaining sterile. The author thinks that Nuttall 
and Thierfelder have proved that bacteria are not needed for nutrition, 
in so far at. least as animal food is concerned. All the same, experi- 
ments with vegetable nutriment are wanted in order to render the case 
complete. 
Coprophilous Bacteria of the Permian Epoch.f — MM. B. Renault 
and C. E. Bertrand, who have repeatedly examined the coprolites from 
the lower gut of fossil fishes of the Permian epoch, have found number- 
less forms of fossil bacteria. The authors’ communication is illustrated 
with photographs of these gigantic microbes. The most frequent form 
* Zeitsclir. f. Hygiene u. Infekt., xvi. (1894). See Bot. Centralbl., v. (1895) 
Beih., p. 125. 
f Ann. Inst. Pasteur, ix. (1895) pp. 896-901 ; and also Zeitsclir. f. Phys. Ckemie, 
xxi. (1895) p. 109. i See ante, p. 178. 
§ La Me'decine Moderne, 1891, No. 70. See Centralbl. f. Bakteriol. u. Para- 
sitenk., 2 te Abt., i. (1895) p. 822. Cf. this Journal, 1895, p. 467. 
