March 16, 1894. 
Although the author formally divides his work into only 
two parts, viz., I. that relating to the structure of Oil 
Foams and IT. that relating to the structure of Protoplasm, 
it may be more conveniently considered as consisting of 
four divisions,—1. treating of the author’s experiments 
with microscopic foams, 2. recounting his observations 
upon living protoplasm, 3. reviewing all known theories 
of protoplasmic structures, and 4. giving Professor 
Biitschli’s own conclusions as to the physical nature of 
protoplasm. 
In the words of the translator, ‘‘ protoplasm is conceived 
of in this work as having the structure of a froth or foam 
in which minute droplets of a watery liquid take the place 
of air in the bubbles of an ordinary foam.” ‘The author 
applies to this formation a term which means pretty 
nearly ‘‘ honeycomb structure,” but which Mr. Minchin 
finds it more convenient to translate as a@/veolus, using as 
the related adjective the word a/zcolar. 
The method of experimentation and comparison made 
use of by the author of this work is of course not wholly 
new, and this is not his first presentation of the subject. 
As far back as 1878 Professor Biitschli broached the 
general idea worked out in the present book, and although 
he has modified his views from time to time to meet the 
criticisms of fellow-investigators, or to accommodate them 
to facts brought to light by his own observations, this may 
be regarded as in the main’a final defence of his original 
thesis,—namely, that protoplasm, while generally present- 
ing an alveolar arrangement, is in itself structureless, and 
that its manifestations of activity are explainable on 
purely physical grounds. 2 
The aims of his experiments have been, first, to produce 
artificial foams of the fineness of those believed to exist 
in protoplasm and comparable with the latter; second, to 
induce in his artificial plastides the phenomena of stream- 
ing, locomotion, and growth by intussusception; and, 
third, to show that the structure of living protoplasm and 
its so-called vital movements are similar in character to 
those produced by his methods. In pursuance of his first 
object he has undoubtedly found a simple method of 
making oil froths with a meshwork as fine as ‘modern 
optical appliances can render visible, and to this extent he 
has matched the reticular appearances brought to light 
during recent years in vegetable and animal protoplasm. 
But, unfortunately, the microscope has not yet reached 
that degree of perfection, even with its latest apochromatic 
objectives and compensating oculars, which will enable 
us to speak with entire positiveness of the real form of 
any of the smallest structures we are able to discern, and 
so, with reference both to these microscopical foams and 
to the reticulated protoplasm of living organisms, we can- 
not at present depend entirely on sight and wholly dis- 
pense with imagination. In his alveolar oil-drops our 
auther properly assumes the right to argue from the larger 
cavities down to the very smallest, and to assume from 
his employment of a structureless colloid that the boundary 
walls and the interconnecting threads are nothing but 
films of oil in different degrees of tension. But in the 
case of protoplasm we may fairly question whether he is 
thus far justified in carrying his analogy beyond the bound 
of mere superficial resemblance. 
In pursuance of hissecond aim, Professor Biitschli has 
found that when the exchange takes place between the 
contents of the oil vacuoles and the surrounding water, a 
streaming movement is set up, the currents of which, both 
within and without the drop, may be made visible by mix- 
ing India ink or other coloring matter with the fluids. 
He has also observed that at this time the drop, which is 
compressed to a thin layer between glasses for microscopti- 
cal examination, is likely to ‘creep somewhat rapidly 
backwards and forwards under the cover glass,” a move- 
SICMEINICIE, 
149 
ment which, he claims, is like that of asimple amoeba, 
The progression is ina line with the streaming motion 
already referred to;—that is to say, there is a point upon 
the surface of the drop at which the interchange between 
its contents and its environing liquid is most active, to- 
wards which point the internal currents converge, and 
from which the external currents diverge, thus creating 
an anterior pole to the drop, and the author himself 
expresses the belief that ‘‘the creeping progressive 
movements are without doubt in connection with such 
streamings.’’ In strongly pressed drops several centres 
of extension currents may arise, and, as the oil then 
spreads in several directions at once, there is created the 
appearance of ‘‘ pseudopodium-like processes,” but ‘‘ such 
drops show, as was to be expected, no actual forward 
movement as a whole.” ‘he author remarks that ‘‘not 
infrequently a drop of the’ kind just described is observed 
to run towards one of the strips of cover-glass employed 
as supports,”’ which plainly suggests that all of his ‘‘ creep- 
ing’? movements may be the result of capillary attraction, 
when they are not produced by the mere pressure of his 
compressorium. 
As to ‘‘growth,” Professor Biitschli is not able to 
present any proof beyond the simple swelling of the drops 
during the first imbibition of water and solution of the 
salt crystals entangled in the oil, by which the conversion 
of the oil into froth is accomplished. In fact all of the 
processes described are but temporary and are strictly 
confined to the period necessary to bring about a state 
of physical equilibrum in each case. Even the streaming 
movements are known to have continued only from twenty- 
four hours to a maximum of six days, apparently in pro- 
portion to the freedom allowed the drop to carry on the 
process of interchange, or to the quantity of matter con- 
cerned in the operation. In any case, the author admits 
that ‘‘ the streams gradually become weaker and weaker, 
and finally cease,” and that ‘‘the duration of the extension 
currents described is, for the most part, relatively short.” 
In this respect, at least, the parallel between oil drops and 
protoplasm is lacking, for, according to the latest and 
most generally accepted belief, the one _ essential 
characteristic of protoplasm is its never ceasing activity, 
and it is this very attribute which now needs explanation 
and to which biologists are devoting the greatest atten- 
tion. Professor Biitschli’s experiments certainly cast no 
more light on this problem than-do the achievements of 
chemists who have approached close to the synthetic con- 
struction of ‘‘ the physical /aszs ” without actually initiating 
in it the vital processes. As to the apparent similarity 
between the so-called creeping of his oil drops, and the 
purposeful and continuous migrations of the protozoa, 
Professor Biitschli finally admits that his explanation 
““seems at present feasible only for amoeboid movement 
inthe strict sense, while other modifications of it, 
especially the formation of the fine pseudopodia of numerous 
Sarkodina, obtain no explanation.” His theory of the 
simplest amoeboid movement ts, however, itself so novel 
and extraordinary that we cannot but think it needs con- 
firmation quite as much as does the phenomenon which it 
is intended to illustrate. Our author’s belief is, that ‘‘ by 
the bursting of some of the superficial alveoli, enchylema 
is poured out upon the free surface of the protoplasmic 
body, where it produces a local dimunition of surface 
tension, and in this way sets up an extension centre 
together with forward movement.” If this theory is ever 
established upon a basis of actual observation it is difficult 
to see why the process may not be witnessed as easily in 
living forms as in artificial foams. On purely speculative 
grounds there are strong objections to the hypothesis, and 
some of these have made so powerful an impression upon 
Professor Biitschli that he is constrained at the last 
