ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 551 
with uniform sarcoplasm holding each set of fibrils together and often 
with granules around each area. With Knoll, the first type of fibre 
may be distinguished as poor in protoplasm (clear), the second as rich 
in protoplasm (dull), but there are transitions between them. The 
effects of various methods of technique on the appearance of the areas 
are described. Other differences are due to the state of contraction, 
alterations in metabolism, &c. 
The fibrils of early embryonic stages do not correspond to the fibrils 
of the fully , formed muscle, but rather to muscle-pillars. Muscle-fibres 
arise by the thickening and longitudinal cleavage of fibrillar tubes. 
The cleavage is always preceded by multiplication of nuclei. Repeated 
cleavage brings the nuclei out of the contractile substance of the 
embryonic fibre to the surface. Here and there even in newly born 
animals the embryonic mode of forming muscle-elements persists. Even 
in well-advanced embryos no strict limit can be drawn between fascia 
and muscle. Striped muscle is one of those tissues in which disruption 
and new formation of elements go hand in hand ; the disruption 
is introduced by a process analogous to contraction ; of this the naked, 
non-nucleated sarcolvtes are structural expressions ; nucleated sarcolytes 
also occur. New formation is due to the freed, axial, nucleated proto- 
plasmic strands or to individual elements of these, the myoblasts of some 
authors. All these conclusions are discussed at length. 
y. General. 
Is there a Cell-life without Micro-organisms.* — Prof. W. Kochs 
has inquired into the dependence of cellular life on a symbiosis with 
bacteria. Thus he tried to find whether there were any living plants 
which did not contain micro-organisms. His method was to sterilize 
the husks of seeds and then let them germinate with proper precautions 
to evade bacteria. Often the experiment failed, but he succeeded in 
rearing plants (though not to maturity) without any bacteria being 
detected in or - about them. The appearance of the dead, but not of 
course putrefying plants, was interesting. By experiments with fruits 
with uninjured skins and dipped in sublimate solution, he showed that 
bacteria are normally absent in the interior. Though results conflict 
not a little, it seems certain that it is often possible to find a drop of 
blood free from bacteria and to keep it from putrefaction. It is also 
known that the eggs of some animals, e. g. Entomostraca, will develope 
after sterilization. From these and other facts Kochs answers his 
question in the affirmative. 
Haacke’s Theory of Gemmaria.f — Dr. W. Haacke responds in a 
lively manner to R. von Lendenfeld’s criticism of his two recent works. 
The critic insinuated that in Haacke’s exposition the favourable facts 
were given undue prominence and the antagonistic facts subordinated ; 
the author denies the impeachment. The critic said that Haacke under- 
valued the mixture of nuclei just because Weismann emphasized it ; the 
author protests against such criticism. Similarly, in regard to many 
more serious points, the author vindicates himself. At the same time, 
he gives further explanations in regard to some of his conclusions. 
* Biol. Centralbl., xiv. (1894) pp. 481-91 (1 fig.). f Tom. cit., pp. 497-513. 
