al i 
January 13, 1923] 
NATURE 
57 
ing the value and utility of Hertwig’s great “ hand- It must not be imagined that Hertwig’s activities 
book.” 
Hertwig, a laboratory worker rather than a field 
naturalist, had no belief in “ das schon morsch gewor- 
dene Lehrgebiiude des Darwinismus,’”’ and to this 
fact we owe the last of his larger text-books—the 
useful and interesting, if not wholly convincing, 
“Das Werden der Organismen,” first published in 
1916 and now in its third edition. 
Oscar Hertwig’s really great, indeed epoch-making, 
contributions to the development of biological 
science are to be found, however, not in his 
text-books, but in a comparatively small group of 
original investigations, some of them carried out 
in co-operation with his brother Richard, which 
are of the most fundamental importance. It was 
in 1875 that Hertwig, forestalling van Beneden by 
a few months, showed for the first time, by his studies 
upon sea-urchin eggs, what was the real nature of 
the fertilisation of the animal egg—that the process 
consisted essentially of the fusion between the nucleus 
of the egg and the nucleus of one single spermatozoon. 
In 1878 there appeared the monograph by the brothers 
Hertwig upon the sense organs and nervous system 
of the meduse—a work published before its time and 
perhaps destined to fill its réle more completely in the 
future with a fuller recognition of the fact that the 
most fundamental function of the nervous system is to 
preserve intact the organic continuity in the animal 
body throughout its evolutionary increase in bulk. 
In the early eighties of last century, Oscar and 
Richard Hertwig, stimulated by the work of English 
morphologists — Huxley, Lankester, and Balfour — 
turned themselves to the investigation of the founda- 
tions of the germ-layer theory, clearing up the muddle 
which had resulted from the non-recognition of what 
we now know by Hertwig’s name, mesenchyme, and 
corroborating and amplifying Lankester’s conception 
of the enteroccelic nature of the ccelom. 
In 1890 Oscar Hertwig published his comparison 
of “ Egg- and Sperm-formation in Ascaris,” in which 
he worked out in minute detail the parallelism in 
gametogenesis in the two sexes, and cleared up the 
mystery of the “ polar bodies,’ long known as char- 
acteristic of the unfertilised animal egg. Hertwig 
showed that male and female gametes are alike formed 
in sets of four, but that in the female sex three of 
each four degenerate, the three degenerate eggs being 
the polar bodies. 
The last of Hertwig’s works that demands mention 
is his study of those extraordinary malformations of 
vertebrate embryos to which he applied the name 
“spina bifida.” In these the body of the embryo is 
divided into two halves by a longitudinal cleft travers- 
ing the notochord and the greater part of the central 
nervous system, and yet this seemingly irreparable 
injury proves no insuperable barrier to continued 
development. In many cases the cleft closes, the 
two halves unite and a perfectly normal individual 
results. Hertwig correlated these monstrosities with 
a hypothetical evolutionary stage in which the neural 
surface of the ancestral vertebrate was traversed by 
a slit-like primitive mouth, and to-day this is still 
the only working hypothesis at our disposal to explain 
a very extraordinary phenomenon. 
NO. 2776, VOL. rit] 
were limited to such fields as are indicated by the 
‘various works to which allusion has been made. He 
interested himself in the social questions of the day, 
and the very last of his publications that has come 
into the writer’s hands is ‘‘ Der Staat als Organisms ” 
(1922), with a trenchant criticism of some of those 
forms of extremism that are so rife at the present time. 

Mr. A. TREVOR-BATTYE. 
Mr. A. TREVoR-BattyeE, who died at Las Palmas on 
December 20, was an accomplished naturalist and 
Arctic traveller. The second son of the Rev. W. 
Wilberforce Battye, he was born in 1855 and adopted 
in 1890 the additional surname of Trevor on succeeding 
to certain estates that had fallen to his father. After 
leaving Oxford, Mr. Trevor-Battye indulged his 
taste for natural history in extensive travels in North 
America, Africa, the Himalayas, and Arctic Europe. 
In 1894, in the yacht Saxon, he visited the little known 
island of Kolguev, in the Barents Sea, with the object 
of devoting the summer to the study of its bird life. 
The Saxon, on returning from a cruise to Novaya 
Zemlya, missed Mr. Trevor-Battye through inability 
to reach the east coast, and returned to England with- 
out him or his companion, Mr. Hyland. The two 
Englishmen joined a party of wandering Samoyedes 
and made good their retreat to the mainland by sledge 
and boat. This was a fruitful expedition and com- 
pleted the exploration of Kolguev. 
In 1896 Mr. Trevor-Battye returned to the Arctic 
regions, accompanying Sir Martin Conway as naturalist 
on his expedition to Spitsbergen. Mr. Trevor-Battye 
made explorations around Dickson Bay and, with Prof. 
Garwood, climbed Hornsunds Tind. A few years later 
he visited Crete and made valuable contributions to 
the knowledge of its natural history. 
Mr. Trevor-Battye was editor of natural history 
in the “ Victoria History of the Counties of England,” 
and of Lord Lilford’s book on British birds. His own 
works included “ Icebound on Kolguev ” (1895); “ A 
Northern Highway of the Tsar ”’ (1897) ; and “ Camping 
in Crete” (1913). ‘‘ Crete: its scenery and natural 
features ”’ was a recent contribution to the Geographical 
Journal (September 1919). 

Dr. FRIDOLIN KRASSER. 
A Few weeks ago Dr. Fridolin Krasser was found 
dead in his laboratory at the Deutsche Technische 
Hochschule at Prague, where for several years he had 
occupied the chair of botany. He was widely known 
as a paleobotanist who had devoted himself to the 
investigation of Mesozoic floras, more especially to 
the study of the large collections of Upper Triassic 
plants from the well-known Lunz beds in the Flof 
Museum of Vienna. In 1887, Dr. Krasser published 
a note on heterophylly inspired by the work of Baron 
Ettingshausen, with whom he was closely associated. 
In 1891 he wrote on the Rhetic floras of Persia ; 
a few years later he turned his attention to the Creta- 
ceous plants of Moravia, and in 1900 and 1905 made 
some interesting contributions to our knowledge of 
Paleozoic and Mesozoic floras of the Far East. 
