Aug. 10, 1871 | 
NATURE 
295 

been known, and the successful employment of reagents which 
appear to mark out its distinction from the other elements of the 
textures. I may remark, however, in passing, that Iam inclined 
to regard contractile protoplasm, whether vegetable or animal, 
as in no instance entirely amorphous or homogeneous, but rather 
as always presenting some minute molecular structure which dis- 
tinguishes it from parts of glassy clearness. Admitting that the 
form it assumes is not necessarily that of a regular cell, and may 
be various and irregular in a few exceptional instances, I am not 
on that account disposed to give up definite structure as one of 
the universal characteristics of organisation in living bodies, I 
would also suggest that the terms formative and nonformative, or 
some such other, would ‘be preferable to those of ‘‘ living and 
dead,” employed by Dr. Beale, to distinguish the protoplasm 
from the cell-wall or its derivatives, as the latter terms are liable 
to introduce confusion, 
Embryology: 
To the discoveries in embryology and development I might 
have been tempted to refer more at large, as being those which 
have had, of all modern research, the greatest effect in extending 
and modifying biological views, but I am warned from entering 
upon a subject in which I might trepass too much on your 
patience. The merits of Wolff as the great first pioneer in the 
accurate observation of the phenomena of development were 
clearly pointed out by Prof. Huxley in his presidential address of 
last year. Under the influence of Dollinger’s teaching, Pander, 
and afterwards Purkinge, Von Baer, and Rathke, established the 
foundations of the modern history of embryology. It was only 
in the year 1827 that the ovum of mammals was discovered by 
Von Baer; the segmentation of the yelk, first observed by 
Prevost and Dumas in the frog’s ovum in 1824, was ascertained 
to be general in succeeding years, so that the whole of the 
interesting and important additions which have followed, and 
have made the history of embryological development a complete 
science, have been included within the eventful period of the life 
of this Association. I need not say how distinguished the 
Germans have been by their contributions to the history of 
animal development. The names of Valentin, R. Wagner, 
Bischoff, Reichert, Kolliker, and Remak are sufficient to indicate 
the most important of the earlier steps in recent progress, without 
attempting to enumerate a host of others who have assisted in 
the great work thus founded. Iam aware that the mere name 
of development suggests to some ideas of a disturbing kind as 
being associated with the theory of evolution recently promulgated. 
To one accustomed during the whole of his career to trace the 
steps by which every living being, including man himself, passes 
from the condition of an almost imperceptible germ, through a 
long series of changes of form and structure into their perfect 
state, the name of development is suggestive rather of that which 
seems to be the common history of all living beings ; and it is 
not wonderful therefore that such a one should regard with 
approval the more extended view which supposes a process of 
development to belong to the whole of nature. How far that 
principle may be carried, to what point the origin of man or any 
animal can by facts or reasoning be traced in the long unchronicled 
history of the world, and whether living beings may arise inde- 
pendently of parents or germs of previously existing organisms, 
or may spring from the direct combination of the elements of 
dead matter, are questions still to be solved, and upon which we 
may expect this section to guide the hesitating opinion of the 
time. I cannot better express the state of opinion in which I find 
myself in regard to the last of these problems than by quoting the 
words of Professor Huxley from his address of last year, p. 1xxxill.: — 
“But though I cannot express this conviction of mine too 
strongly (viz., that the evidence of the most careful experiments 
is opposed to the occurrence of spontaneous generation), I must 
carefully guard myself against the supposition that I intend to 
suggest that“no such thing as abiogenesis ever has taken place in 
the past, or ever will take place in the future. With organic 
chemistry, molecular physics, and physiology yet in their infancy, 
and every day making prodigious strides, I think it would be the 
height of presumption for any man to say that the conditions 
under which matter assumes the properties we call ‘vital,’ may 
not some day be artificially brought together. And again, if it 
were given me to look beyond the abyss of geologically recorded 
time, to the still more remote period when the earth was passing 
through physical and chemical conditions which it can no more 
see again than a man can recall his infancy, I should expect to be 
a witness of the evolution of living protoplasm from not living 

course to which many of you must have listened last evening 
with admiration, Sir William Thomson said—‘‘ The essence of 
science, as is well illustrated by astronomy and cosmical physics, 
consists in inferring antecedent conditions, and anticipating future 
evolutions, from phenomena which have actually come under ob- 
servation. In biology, the difficulties of successfully acting up to 
this ideal are prodigious. Our code of biological law is an expres- 
sion of our ignorance as well as of our knowledge.” And again, 
‘Search for spontaneous generation out of inorganic materials ; 
let any one not satisfied with the purely negative testimony, of 
which we have now so much against it, throw himself into the 
inquiry. Such investigations as those of Pasteur, Pouchet, and 
Bastian are among the most interesting and momentous in the 
whole range of natural history; and their results, whether 
positive or negative, must richly reward the most careful and 
laborious experimenting.” 
Organic Chemistry and Vital Force 
The consideration of the finest discoverable structures of the 
organised parts of living bodies is intimately bound up with that 
of their chemical composition and properties. The progress 
which has been made in organic chemistry belongs not only to 
the knowledge of the composition of the constituents of organised 
bodies, but also to the manner in which that composition is 
chemically viewed. Its peculiar feature, especially as related to 
biological investigation, consists in the results of the introduction 
of the synthetic method of research, which has enabled the 
chemist to imitate or to form artificially a greater and greater 
number of the organic compounds. In 1828 the first of these 
substances was formed by Wohler, by a synthetic process, as 
cyanate of ammonia, or urea. But still, at that time, though a 
few no doubt entertained juster views, the opinion generally pre- 
vailed among chemists and physiologists that there was some 
great and fundamental difference in the chemical phenomena and 
laws of organic and inorganic nature. Now, however, this sup- 
posed barrier has been in a great measure broken down and re- 
moved, and chemists, with almost one accord, regard the laws of 
combination of the elements as essentially the same in both classes 
of bodies, whatever differences may exist in actual composition, 
or in the reactions of organic bodies in the more complex and 
often obscure conditions of vitality, as compared with the simpler, 
and, on the whole, better known phenomena of a chemical nature 
observed in the mineral kingdom. Thus, by the synthetic method, 
there have been formed among the simpler organic compounds a 
great number of alcohols, hydrocarbons, and fatty acids. But 
the most remarkable example of the synthetic formation of an 
organic compound is that of the alkaloid conia, as recently 
obtained by Hugo Schiff by certain reactions from butyric 
aldehyde, itself an artificial product. The substance so 
formed, and its compounds, possess all the properties of the 
natural conia—chemical, physical, and physiological—being 
equally poisonous with it. The colouring-matter of madder, or 
alizarine, is another organic compound which has been formed by 
artificial processes. It is true that the organised or containing 
solid, either of vegetable or animal bodies, has not as yet yielded 
to the ingenuity of chemical artifice ; nor, indeed, is the actual 
composition of one of the most important of these, albumen and 
its allies, fully known. But as chemists have only recently begun 
to discover the track by which they may be led to the synthesis 
of organic compounds, it is warrantable to hope that ere long 
cellulose and lignine may be formed ; and, great as the difficulties 
with regard to the albumenoid compounds may at present appear, 
the synthetic formation of these is by no means to be despaired 
of, but, on the contrary, may with confidence be expected to 
crown their efforts. From all recent research, therefore, it ap- 
pears to result that the general nature of the properties belonging 
to the products of animal and vegetable life, can no longer be re- 
garded as different from those of minerals, in so far at least as 
they are the subject of chemical and physical investigation. The 
union of elements and their separation, whether occurring in an 
animal, a vegetable, or a mineral body, must be looked upon as 
dependent on innate powers or properties belonging to the elements 
themselves ; and the phenomena of change of composition of or- 
ganic bodies occurring in the living state are not the less chemical 
because they are different from those observed in inorganic 
nature. All chemical actions are liable to vary according to the 
conditions in which they occur, and many instances might be ad- 
duced of most remarkable variations of this kind, observed in the 
chemistry of dead bodies from very slight changes of electrical, 
calorific, mechanical, and other conditions. But because the con- 
matter.” I will quote further a few wise words from the dis- | ditions of action or change are infinitely more complex and far 
