ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
657 
in review, the one receiving favourable notice being that of Zopf, 
although Miquel’s system finds commendation, and that of De Toni and 
Trevisan is distinguished as being the most recent and most thorough. 
This last, published in 1889, describes over 650 species ; and when it is 
remembered that Winter’s list published in 1881 contained only 69 
species, the thought naturally occurs that something ought to be done 
to keep down or diminish this ever-multiplying horde. 
According to the author one of the most prolific sources of this 
generation of multiple species has been their growth under different 
conditions, and “ if we could have every ‘ species ’ that will grow on a 
normal gelatin at 20° C. compared on that medium and at that tempe- 
rature under like conditions, the advantage would be enormous, and 
similarly with all * species ’ which will only flourish in bouillon at 35° C., 
and so on.” 
It is suggested that those concerned with Schizomycetes (especially 
persons with a floral or ideal bias, and those with a hygienic or practical 
turn) should come to some arrangement, so that in describing a new 
species certain definite data marks and characters should invariably be 
given : — For example, (1) habitat ; (2) nutrient medium ; (3) gaseous 
environment ; (4) temperature ; (5) morphology and life-history ; (6) 
special behaviour ; (7) whether pathogenic, saprophytic, nitrifying, &c. 
Of course the foregoing seven points are thrown out as suggestions 
to form a sort of rule-of-thumb method of examination which should be 
applied to every organism, and these points are not meant to exclude 
any other marks or characters suitable for identifying or locating an 
organism and describing a species. 
Nitrification.* — The explanation of the difference between the nitri- 
fying process as observed under artificial and under natural conditions 
has been sought in a weakening of the ferment of the artificial culti- 
vations, and in the co-operation of two different kinds of nitrifying 
organisms when acting under natural conditions, i. e. in the soil. 
From experiments made with soil taken from all quarters of the world 
Herr Winogradsky concludes that two organisms are employed in natural 
nitrification, one forming nitrite and the other nitrate, and hence the 
process is completed in two periods. The two micro-organisms were 
isolated on solid media, the nitrate-former being oval, about 0*5 p, long, 
and ljg-2 times less in breadth. The nitrite-forming organisms are oval 
or spheroidal, and about double the size of the nitrate-formers. 
Further investigations showed that in normal earth, nitrate only is 
formed, the production of nitrous acid being a transitory phenomenon, 
and, even in the presence of considerable quantities of ammonia, being 
oxidized as soon as formed. The nitrite ferment, either under natural 
or under artificial conditions, can only form nitrite, and nitrous acid 
thus formed remains as such in the ground if the nitrate-former be 
absent. 
If, however, nitrate as well as nitrite forming ferment be added to 
sterilized earth, the process is completed in the natural way, only the 
merest traces of nitrous acid appearing. 
* Annales de l’lnstitut Pasteur, 1891, p. 577. See Centralbl. f. Bakteriol. u. 
Parasitenk., xi. (1892) pp. 195-8. Cf. this Journal, 1891, p. 680. 
1892. 2 y 
