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THE

WADE R

QUARTER-CENTURY BOOK

A COLLECTION OF ORIGINAI, PAPERS DEDICATED TO

PROFESSOR BURT GREEN WILDER

AT THE CLOSE OF HIS TWENTY-FIFTH
YEAR OF SERVICE
IN CORNELL UNIVERSITY
(7868-7893)

BY

SOME OF HIS FORMER STUDENTS

ITHACA, N. Y.
COMSTOCK PUBLISHING CO.

1893

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Entered, according to act of Congress, in the year 1893, by the
COMSTOCK PUBLISHING COMPANY, .
in the Office of the Librarian of Congress at Washington. att)"

O BURT GREEN WILDER,
B.S., M.D., PROFESSOR OF
PHYSIOLOGY, VERTEBRATE
ZOOLOGY, AND NEUROLOGY
IN CORNELL UNIVERSITY,
THIS VOLUME IS DEDICAT-
ED BY HIS FORMER PUPILS,

AS A TESTIMONIAL, OF
THEIR APPRECIATION OF HIS UNSEL-
PiSh. DEVOTION, TO TRE UNIVERSITY,
AND IN GRATEFUL REMEMBRANCE OF
THE INSPIRATION \OF (His. TEACHING
AND EXAMPLE.

i ABE Et (OPM COuN hE NPS

AND OF CONTRIBUTORS.

PAGE,

PORTRAIT OF PROFESSOR BURT GREEN WILDER. Engraved by
John P. Davis, Ere of: the BORED of American Wooa-
Engravers... . . . . Frontispiece.

List of the more important scientific publications of Professor
Wilder. . 2 Se De RIE. ie nen

TABLE showing the number of students taught by Professor Wilder

DAVID STARR JORDAN, LL.D., President of the Leland Stanford
Junior University. Temperature and Vertebre—A Study in
Evolution, Being a Discussion of the Relations of the Numbers
of Vertebraze among Fishes to the Temperature of the Water
and to the Character of the Struggle for Existence. .

ANNA BOTSFORD Comstock, B.S., Member of the Society of
American Wood-Engravers, Natural History Artist. 1. En-
graving of a Cat (following page 36). II. Engravings of Moths
(Plate I, illustrating the Essay on Evolution and Taxonomy).

JoHN HENRY ComsTock, B.S., Professor of Entomology and Gen-
eral Invertebrate Zoology in Cornell University, and Professor
of Entomology in The Leland Stanford Junior University.
Evolution and Taxonomy. An Essay on the Application of
the Theory of Natural Selection in the Classification of Ani-
mals and Plants, Illustrated by a Study of the Evolution of the
Wings of Insects, and by a Contribution to the Classification of
the pee eRe oe three plates, and thirty-three figures in
the text) . SERRE ee a CAG: One ga ate Reet we OE ees

EUGENE ROLLIN Corson, B.S., M.D., Physician and Surgeon,
Savannah, Ga. The Vital Equation of the Colored Race and its
Future in the United States. F

LELAND O. HowarbD, M.S., First Assistant EE See UES:
Department of Agriculture, Washington, D. C. The Corre-
lation of Structure and Host-Relation among the Encyrtine .

THEOBALD SMITH, Ph.B., M.D., Chief of the Division of Animal
Pathology, Bureau of Animal Industry, U. S. Department
of Agriculture, Professor of Bacteriology and Hygiene in the
Medical Department of the Columbian University, Washing-
ton, D. C. The Fermentation Tube with Special Reference to
Anaerobiosis and Gas Production among Bacteria, fone one
plate) . Bae dete aaah ALU fe ie

WILLIAM CHRISTOPHER KRAUSS, B.S., M.D., Physician, Professor
of Pathology, Medical Department of Niagara University, Buf-
falo, N. Y. Muscular Atrophy Considered as a ali ae
(with one plate and three figures in the text) .

a 4 % \, “5

13

37

115

177

187

235

vi Table of Contents

SUSANNA PHELPS GAGE, Ph.B. The Brain of Diemyctylus viride-
scens, from Larval to Adult Life, and Comparisons with the
Brain of Amia and of Petromyzon, (with eight plates). . . . 259

HERMANN MICHAEL BIGGS, A.M., M.D., Professor Materia Medi-
ca, Therapeutics, and Nervous Diseases, Bellevue Hospital
Medical College, Visiting Physician and Pathologist, Belle-
vue Hospital, Neurologist and Pathologist to the Flospital
of the Work House and Alms House, Chief Inspector Div.
Path. Bact. and Disinfection, N. ¥. City Flealth Department.
A Bacterial Study of Acute Cerebral and Cerebro- Waar ane
Menitigitis!. ).) 2 i BB EEN gts

JOHN CASPER BRANNER, Ph.D. pie of Geology in the Le-
land Stanford Junior University. Observations upon the Ero-
sion in the Hydrographic Basin of the Arkansas River above
Tittle Rocky Fi se Ey ee a (Det or

VERANUS ALVA MOORE, B.S., M.D., First Assistant in the Dt-
vision of Animal Pathology, Bureau of Animal Industry, U.
S. Department of Agriculture, Assistant Demonstrator of
Pathological Histology in the Medical Department of the Col-
umbian University, Washington, D. C. The Character of the
Flagella on the Bacillus Cholerze Suis (Salmon and Smith),
Bacillus Coli Communis (Escherich), and the Bacillus Typhi
Abdominalis (Eberth), (with one:plate). .....-.... . 339

GRANT SHERMAN HOPKINS, D.Sc., /ustructorin Anatomy, Micro-
scopy, and Embryology in Cornell University. The Lympha-
tics and Enteric Epithelium of Amia calva, (with two plates) 367

PIERRE AUGUSTINE FISH, B.S., /ustructor in Physiology, Verte-
brate Zoology, and Neurology in Cornell University, and In-
structor in Zoology, Marine Biological Laboratory at Wood's
Holl. Brain Preservation, with a Résumé of some Old and
New Methods, (with one plate)... . 2 3. . 215). APs, stole

WILLIAM RUSSELL DUDLEY, M.S., Professor of Botany in the Le-
land Stanford Junior University. The Genus es lospet
(with two plates). . . 403

SIMON HENRY GAGE, B.S., Associate Professor ye Anatomy, H1s-
tology, and Embryology in Cornell University. The Lake and
Brook Lampreys of New York, ace those of Pons and
Seneca Lakes, (with eight plates) . : 421

MILTON JOSIAH ROBERTS, M.D., late ee Surgeon, New
York City. Flashlight Photography in Surgery and Medicine.
(Dr. Roberts’s contribution, left incomplete by his death, could
not be printed in this volume. )

LIST OF THE MORE IMPORTANT SCIENTIFIC PUBLICATIONS
OF BURT GREEN WILDER, B.S., M.D., PROFESSOR OF
PHYSIOLOGY, VERTEBRATE ZOOLOGY AND NEUROLOGY
IN CORNELL UNIVERSITY.

1861. Contributions to the comparative myology of the chimpanzee
[1861]. Boston Jour. Nat. Hist., VII, 1859-1863, pp. 352-384.

’ 4862, Note on the muscles of the hog’s snout. Boston, Soc. Nat. Hist.
Proc exs 18625 p. i.

1864. Histories of two surgical specimens in the Army Medical Muse-
um. Boston, Med. and Surg. Jour., LX XI, 1864, pp. 292-294. Med.
and Surg. History of the War, pt. I, pp. 427-533.

1866. On the Nephila plumipes or silk-spider of South Carolina
[1865]. Boston, Soc. Nat. Hist. Proc., X, 1866, pp. 200-210; 2 fig.

On morphology and teleology, especially in the limbs of mamma-
lia | 1863]. Boston, Soc. Nat. Hist., Mem. I, 1866-69, pp. 46-80;
3 fig.

A case of imperforate ear in an adult man [1865]. Boston, Soc.
Nat. Hist. Proc., X, 1866, p. 222.

Pathological polarity, or what has been called symmetry in disease.
Bostou, Med. and Surg. Jonr., LX XIV, 1866, pp. 189-198.

‘Termeyer’s ‘‘ Researches and experithents upon silk from spiders :
1810-1820.’ Translation revised. Essex Institute Proc., V, 1866,
PP. 51-79; 2 fig.

1867. On the morphological value and relations of the human hand.
[Abstract of a paper read before the National Academy of Sciences,
Aug. 1866. Amer. Jour. Sci., Series II, XLIV, 1867, pp. 44-48.

The hand as an unruly member. Amer. Naturalist, I, 1867, pp.
414-423, 482-491, 631-638 ; 9 fig.

1868. On the Nephila plumipes or silk-spider [1865]. Amer. Acad.
Proc., VII, 1868, pp. 52-57-

On a cat with supernumerary digits [1865]. Boston, Soc. Nat.
Hist. Proc., XI, 15638, pp. 3-6.

The harmilessness of the bite of Nephila plumipes [1866]. Boston,
Soc. Nat. Hist. Proc., XI, 1868, p. 7.

On a method of recording and arranging information [1867]. Bos-
ton, Proc. Nat. Hist. Soc., XI, 1868, p. 242.

On symmetry and distorted symmetry in the leaves of plants
[1867]. Boston, Soc. Nat. Hist. Proc., XI, 1868, pp. 313-315 ; 2 fig.

Extra digits. Mass. Med. Soc. Publications. (Read at the Annual
Meeting, June, 1868), II, 1868, pp. 22; 1 plate.

How spiders begin their webs [1868]. Amer. Naturalist, II, 1869,
pp. 214-215; Zoologist, III, 1868, p. 1301; Bruxelles Soc. Entom.
Belge Annal., XIII, 1869-1870, pp. II-III.

2 Scientific Publications of

1870. Human Locomotion. How we stand, walk and run. Pp. 18;
18 fig. New York, 1870.

1871. Intermembral homologies, the correspondence of the anterior
and posterior limbs of vertebrates [1871]. Boston, Proc. Nat. Hist.
Soc., XIV, 1871, pp. 154-188, 309-339, 299-420; 5 fig.

1873. Cyno-phrenology. Boston, Med. and Surg. Jour., LX XXVIII,
1873, pp. 73-78.

The outer cerebral fissures of mammalia (especially of the carni-
vora), and the limits of their homologies. Amer. Assoc. Adv. Sci.
Proc., XXII, 1873, (pt. 2), pp. 214-234; 19 fig.

Cerebral variation in domestic dogs and its bearing upon scientific
phrenology. Amer. Assoc. Adv. Sci. Proc., XXII, 1873, (pt. 2), pp.
234-249 ; 6 fig.

Lateral asymmetry in the brains of adouble human monster. Amer.
Assoc. Adv. Sci. Proc., XXII, 1873, (pt. 2), pp. 250-251 ; 4 fig.

The papillary representative of two arms in a double human mon-
ster, with a note on a mummied double monster from Peru. Amer.
Assoc. Adv. Sci. Proc., XXII, 1873, (pt. 2), pp. 251-256; 3 fig.

The habits and parasites of Epeira [Argiope] riparia, with a note
on the moulting of Nephila plumipes. Amer. Assoc. Adv. Sci. Proc.,
XXII, 1873, (pt. 2), pp. 257-263; 8 fig.

The nets of Epeira [Argiope], Nephila and Hyptiotes [Mithras}.
Amer. Assoc. Adv. Sci. Proc., XXII, 1873, (pt. 2), pp. 264-274; 3 fig.

On the lateral position of the vent in Amphioxus [ Branchiostoma],
and in larve of Rana pipiens [Catesbiana]. Amer. Assoc. Adv.
Sci. Proc., XXII, 1873, (pt. 2), pp. 275-300; 10 fig.

On the composition of the carpus in dogs. Amer. Assoc. Adv. Sci.
Proc., XXII, (pt. 2), 1873, pp. 301-302 ; 3 fig.

Variation in the condition of the sense-organs in foetal pigs of the
same litter. Amer. Assoc. Adv. Sci. Proc., XXII, 1873, (pt. 2), pp.
303-304 ; 2 fig.

The pectoral muscles of mammalia. Amer. Assoc. Adv. Sci. Proc.,
XXII, (pt. 2), 1873, pp. 305-307.

Variation of the pectoral muscles of domestic dogs Amer. Assoc.
Adv. Sci. Proc., XXII, 1873, (pt. 2), p. 308.

The need of a uniform position for anatomical figures, with a recom-
mendation that the head be always turned toward the left. Amer.
Assoc. Adv. Sci. Proc., XXII, (pt. 2), 1873, p. 274.

The present aspect of the question of intermembral homologies.
Amer. Assoc. Adv. Sci. Proc., XXII, (pt. 2), 1873, p. 303.

1874. Note on the gestation of the little brown bat, Vespertilio subula-
tus. Amer. Soc. Adv. Sci. Proc., XXIII, 1874, pp. 141-143.

A baby fox. Popular Science Monthly, V, 1874, pp. 443-447 ; I fig.
Jeffries Wyman. Old and New. XI, 1874, pp. 533-544.

1875. Preliminary medical education. Boston, Med. and Surg. Jour.,
XCII, 1875, pp. 2.

On a foetal manatee and cetacean, with remarks upon the affinities
and ancestry of the Sirenia. [Abstract of a communication before
the Bost. Soc. Nat. Hist., April 7, 1875]. Amer. Jour. Sci., 1875;
Series III, pp 105-114; 1 plate.

Burt Green Wilder 3

Notes on the American Ganoids. I. On the respiratory actions of
Amia and Lepidosteus. 11. On the transformations of the tail of
Lepidosteus. \1I. On the transformation of the pectoral fins of Le-
pidosteus. IV. On the brains of Amia, Lepidosteus, Acipenser and
Polyodon. Amer. Assoc. Adv. Sci. Proc., XXIV, 1875, pp. 151-193;
3 plates. Proc. Bost. Soc. Nat. Hist., XIX, p. 337.

The triangle spider. Popular Science Monthly, VI, 1874-5, pp.
641-655; 11 fig.

Bats and their young. Popular Science Monthly, VII, 1875, pp.
641-652; I1 fig.

What young people should know. 8°, pp. 212; 26 fig. Boston,
1875.

1876. On the brains of fishes. Phil. Acad. Proc., XX XVIII, 1876, pp.
51-53-

Note on the development and homologies of the anterior brain-
mass with sharks and skates. Amer. Jour. Sci., Series III, XII, 1876,
Pp. 103-105; I fig.

A brief account of the development and general structure of the
brain. 8°. pp. 7; 5 fig. Ithaca, 1876.

On the serrated appendages [serrule] of the throat of Amza.
Amer. Assoc. Adv. Sci. Proc., XXV, 1876, pp. 259-263; I plate.

On the tail of Amia. Amer. Assoc. Adv. Sci. Proc., XXV, 1876,
pp. 264-267.

On the brains of some fish-like vertebrates. Amer. Assoc. Adv.
Sci. Proc., XXV, 1876, pp. 257-259.

Notes of lectures on physiology and hygiene. 8°. pp. 63. Ithaca,
1876.

1877. On the brain of Chimera monstrosa. Phil. Acad. Proc., XXIX,
1877, pp. 219-250; I plate.

The external branchiz of the embryo Pifa. Amer. Naturalist, XI,
1877, pp. 491-492.

Should comparative anatomy be included in a medical course?
(Introductory lecture in the Medical School of Maine, 1877). N. Y.
Med. Jour., XXVI, 1877, pp. 337-369.

Garpikes, old and young. Popular Science Monthly, XI, pp. I-12,
186-195 ; 10 fig.

On the respiration of Amia. Amer. Assoc. Adv. Sci. Proc., XXVI,
1877, pp. 306-313.

1878. An apparatus to show the action of the diaphragm in respiration.

Boston, Soc. Nat. Hist. Proc., XIX, 1878, p. 337.

On a remnant of the spiracle in Amia and Lepidosteus. Amer.
Assoc. Adv. Sci., 1878. (Unpublished ; see Amer. Naturalist, XIX,
Pp. Igo).

1879. The anatomical uses of the cat. N. Y. Med. Jour., XXX, 1879,

PP. 347-360.

Frozen sections of the cat preserved in alcohol. Amer. Assoc. Adv.
Sci., 1879; N. Y. Med. Record, XV, 1879, p. 311.

Emergencies. How to avoid them and how to meet them. 16°.
pp. 40; 3 fig. New York, 1879-1888.

Health notes for students. 16°. pp. 24. Ithaca, 1879. New York,
1883, pp. 58, 1890, pp. 75.

4 Scientific Publications of

1880. Preliminary laryngoscopy upon the cat. Laryngol. Arch. I, 1880,
PP. 50-SI.

The cerebral fissures of the domestic cat (Felis domestica). Science,
I, 1880, pp. 49-51; 2 fig.

The two kinds of vivisection, seztisection and callisection. N.Y.
Med. Record, XVIII, 1880, p. 219; Nature, XXII, 1880, p. 517;
Science, I, 1880, p. 210.

The foramina of Monro; some questious of anatomical history.
Boston, Med. Surg. Jour., CIII, 1880, pp. 152-154. f

The foramina of Monro in man and the domestic cat. Amer. Assoc.
Adv. Sci., 1880; N. Y. Med. Record, XVIII, 1580, p. 328.

Partial revision of the nomenclature of the brain. Amer. Assoc.
Adv. Sci., 1880; N. Y. Med. Record, XVIII, 1880, p. 328.

The crista fornicis, a part of the mammalian brain apparently unob-
served hitherto. Amer. Assoc. Adv. Sci., 1880; N. Y. Med. Record,
XVIII, 1880, p. 328.

Criticism of the accounts of the brains of the lower vertebrates
given in Packard’s Zoology. Amer. Jour. of Science, XIX, 1880, pp.
I-2.

1881. Criticism of Spitzka’s ‘‘ Notes on the anatomy of the encephalon,
ete.’? Science, II, 1881, p. 48.

A partial revision of anatomical nomenclature, with special refer-
ence to that of the brain. Science, II, 1881, pp. 122-126, 133-138.

How to obtain the brain of the cat. Science, II, 1881, pp. 158-161.

The brain of the cat (Felis domestica). A preliminary account of
the gross anatomy. Amer. Phil. Soc. Proc., XIX, 1881, pp. 524-562 ;
4 plates.

On a mesal [mesad] cusp of the deciduous, mandibular canine of
the domestic cat (Felis domestica). Amer. Assoc. Adv. Sci. Proc.,
XXX, 1881, p. 242.

1882. Note on the ectal (‘‘apparent’’) origin of the N. érigeminus in
the cat. Amer. Jour. Neurol. and Psychiatry, I, 1882, pp. 337-338.

The habits of Cryptobranchus [Megalobatrachus| Amer. Assoc.
Adv. Sci. Proc., XX XI, 1882, p. 482. Amer. Naturalist, XVI, p. 816.

Anatomical Technology as applied to the domestic cat ; an intro-
duction to human, veterinary and comparative anatomy. New York,
1882. 2d revised edition, 1886. pp. 600, 120 fig., 4 plates. Senior
author with S. H. Gage.

1883. Some points in the anatomy of the human brain. Amer. Neurol.
Assoc. Trans., 1883, Jour. Nerv. and Ment. Dis., N. S., VIII, 1883,
pp. 85-86.

On the removal and preservation of the human brain. Amer.
Neurol. Assoc. Trans., 1883; Jour. Nerv. and Ment. Dis., N. S., VIII,
1883, pp. 81-82.

On the brain of a cat lacking the callosum. [Amer. Assoc. Adv. Sci.,
1879]. Amer. Neurol. Assoc., 1883. Amer. Jour. Neurol. and Psychi-
atry, II, 1883, pp. 491-499; 4fig. Jour. Nerv. and Ment. Dis., N. S.,
VIII, 1883, p. 62 (Abstr.) Neurol. Centralblatt, II, 517 (Abstr. )

On the alleged homology of the carnivoral /issura cruciata with
the primatial /. centralis. Amer. Neurol. Assoc. Trans., 1883. Jour.
Nerv. and Ment. Dis., N.S., VIII, 1883, pp. 62-63.

Burt Green Wilder 5

Preliminary medical education at Cornell University. Med. Stu-
dent, I, 1883, p. 3.

Vivisection in the State of New York. Popular Science Monthly,
XXIII, 1883, pp. 169-180.

On the use of vaseline to prevent the leakage or evaporation of al-
cohol from specimen jars. Amer. Assoc. Adv. Sci. Proc., 1883, XXXII,
p. 318. N. Y. Med. Jour., XX XIII, 1883, p. 244. Also in Colorado
Med. Jour., 1883, and Internat. Rev. of Med. and Surg. Technics,
1884. Senior author with S. H. Gage.

1884. Methods of studying the brain. The “Cartwright Lectures’’ for
1834. N. Y. Med. Jour, XXXIX, 1884, pp. 141-148, 177-183, 205-
209. 233-237, 373-377) 457-461, 513-516, 653-656; XL, 113-116; 64 fig.
(Abstracts in N. Y. Med. Record, XXV, 1884, pp. 141-143, 197-199,
225-227, 365-367, 449-450, 545-546. )

On encephalic nomenclature. Amer. Neurol. Assoc. Trans., 1884.
Jour. Nerv. and Ment. Dis., 1884, pp. 18, 50.

Do the cerebellum and the oblongata represent two encephalic seg-
ments or only one? Amer. Assoc. Adv. Sci. Proc:, XXXITII, 1884,
pp. 523-525; Science, IV, 1884, p. 341; N. Y. Med. Jour., XL, 1884,
Pp. 324.

On some points in anatomical nomenclature. Amer. Assoc. Adv.
Sci. Proc., XX XIII, 1884, pp. 528-529.

The existence and dorsal circumscription of the porta (‘‘ Foramen
Monroi’’) in the adult human brain. Amer. Assoc. Ady. Sci. Proc.,
XXXIII, 1884, p. 526; N. Y. Med. Jour., XL, 1884, p. 324.

The relative position of the cerebrum and the cerebellum in the an-
thropoid apes. Amer. Assoc. Adv. Sci. Proc., XX XIII, 1884, p. 527.

Exhibition of preparations illustrating (@) the existence and cir-
cumscription of the portae (foramina Monrot) in the adult human
brain ; (6) the presence of the cris¢a fornicis in foetal and new-born
human brains; (c) two additional cases of absence of the callosum in
the domestic cat; (d@) the covering of the cerebellum by the cerebrum
in a young chimpanzee whose brain was hardened within the skull.
Jour. Nerv. and Ment. Dis., XI, 1884 Proceedings of the tenth
annual meeting of the American Neurological Association, 1884, pp.
11-13.

The foramen of Magendie in man and the cat. N. Y. Med. Jour.,
XXXIX, 1884, p. 458.

1885. The use of slips in scientific correspondence. [Soc. Natural. East.
U. S., 1884.] Science, V, 1885, p. 44.

Encephalic nomenclature. Ccelian terminology: the names of
the cavities of the brain and myelon. N. Y: Med. Jour., XLI, pp.
325-328, 354-357, 1885; 8 fig.

Paronymy versus heteronymy as neuronymic principles. Presiden-
tial address at the 11th annual meeting of the Amer. Neurological
Assoc., 1885. Jour. Nerv. and Ment. Dis., XII, pp. 21. (Abstr.
in Neurologisches Centralbl., Dec. 15, 1885.)

Educational museums of vertebrates. Address (as vice-president)
before the Biological section of the Amer. Assoc. Adv. Sci. Proc.
XXXIV, 1885, pp. 263-281. (Abstr. in Science, VI, 1885, pp. 222-
224.)

On two little-known cerebral fissures, with suggestions as to fissural
and gyral names. Amer. Neurological Assoc. Trans., 1885. Jour.

6 Scientific Publications of

Nerv. and Ment. Dis., XII, 1885, pp. 350-352. (Abstr. in Neurolo-
gisches Centralblatt, Dec. 15, 1885).

On a seldom-described artery (4. ¢ermatica), with suggestions as
to the names of the principal encephalic arteries. Amer. Neurol.
Assoc. Trans , 1885. Jour. of Nerv. and Mental Dis., 1885, XII, pp.
2. (Abstracts in N. Y. Med. Jour. and N. Y. Med. Record, June 27,
1885, and in Neurologisches Centralblatt, Dec. 15, 1885).

The names of the encephalic arteries. N. Y. Med. Jour., Nov. 28,
1885.

Neuronymy. N. Y. Med. Record, Aug. I, 1885, p. 139.

Exhibition of preparations illustrating (a) the enlargement, yet
complete circumscription of the porta in an alinjected hydrencephal ;
(6) the continuity of the diaccelian endyma from the mesal surface
of the thalamus over the habena to the diatele ; (c) the insula in a
dog, monkey, chimpanzee and porpoise. Trans. Amer. Neurolog.
Assoc., 1885, pp. 49-51. Jour. Nerv. and Ment. Dis, XII, 1885, pp.
364-365.

Experiments antagonizing the view that the serrulz (serrated ap-
pendages) of Amzia are accessory respiratory organs. Amer. Assoc-
Adv. Sci. Proc., XX XIV., 1885, pp. 313-315.

Address. Proceedings at the unveiling of the tablet to the memory
of Louis Agassiz. June 17, 1885, pp. 22-27.

1886. The collocation of a suture and a fissure in the human fcetus.
Jour. Nerv. and Ment. Dis., XIII, 1886, pp. 463-468, 1 fig. (Ab-
stracts in N. Y. Med. Record, July 31, 1886; Science, Aug. 6, 1886
and Medical News, Aug. 7, 1886.)

Notes on the brain. Jour. Nerv. and Ment. Dis., XIII., 1886, pp.
464-472. (Abstracts as above).

Exhibition of the medisected, alinjected head of a murderer.
Amer. Neurol. Assoc. Trans, 1886. Jour. Nerv. and Ment. Dis.,
XIII, 1886, p. 633. (Abstracts as above).

Remarks upon a living frog which was decerebrized more than
seven months ago. Amer. Neurol. Assoc. Trans., 1886. Jour. Nerv.
and Ment. Dis., XIII., 1886, pp. 622-623. (Abstracts as above).

The paroccipital, a newly-recognized fissural integer. Jour. Nerv.
and Ment. Dis., XIII., 1886, pp. 301-315, 5; fig. (Abstract in Neu-
rol. Centralbl., V., p. 501.)

The paroccipital fissure. Letter to the editor N. Y. Medical Re-
cord, Oct. 2, 1886, pp. 389-390.

Human cerebral fissures, their relations and names and the methods
of studying them. American Naturalist, XX., 1886, pp. 901-902; I
plate.

Notes on the foramen of Magendie in man and the cat. Jour.
Nerv. and Ment. Dis., XIII., 1886, pp. 206-207.

1887. The dipnoan brain. (Abstract of a paper on the brain of Cerato-
dus, with remarks upon classification and the general morphology of
the vertebrate brain, read by invitation before the National Academy
of Sciences, April 22, 1887). American Naturalist, XXI., 1887, pp.
544-548, 3 fig.

Remarks on the classification of vertebtates. Amer. Naturalist,
XXI, 1887, pp. 913-917; (Abstr. in Amer. Assoc. Adv. Sci. Proc.,
XXXVI, 1887, p. 251). See correction. Amer. Naturalist, XXI,
1887, p. 1033. :

Burt Green Wilder 7

A sketch of the life of W. S. Barnard. American Naturalist, XXI,
1887, pp. 1136-1137.

1888. The relation of the thalamus to the paraccele (lateral ventricle).
Jour. Nerv. and Ment. Dis., XIV, 1889, pp. 436-443, 2 fig. Also
Amer. Neurol. Assoc. Trans., 1888, pp. 313-320.

With F. P. Foster.—An illustrated encyclopzdic medical diction-
ary, being a dictionary of the technical terms used by writers on
medicine and the collateral sciences in the Latin, English, French,
and German languages. Vol. I. 1888, Vol. II, 1890. Vol. III, 1892,
4°. New York.

“ Professor Wilder furnished lists of the [10.500] terms used by writers on the
anatomy of the central nervous system, with bibliographical references.’’—Preface.

As Chairman.—Reports of the committee on anatomical nomen-
clature with special reference to the brain. Amer. Assoc. Adv. Sci.
Proc., 1888, 1889, 1890.

188Q. Brain, gross or macroscopic anatomy. Reference Handbook of

the Medical Sciences, A. H. Buck, editor, VIII, 1889, pp. 107-164;
104 fig.

Brain, malformations of, which are morphologically instructive.
Same, pp. 189-194 ; Io fig.

Brain, removal, preservation and dissection of. Same, pp. 195-201;
5 fig.

The relation of the thalamus to the paraccele, especially in the
apes. Assoc. Amer. Anatomists, Records, 1889, p. 20. (See also
Note on p. 317 of first paper in 1888.)

The heart as the basis of an intrinsic toponymy. Assoc. Amer.
Anatomists, Records, 1889, p. 25.

As Secretary.—Preliminary reports of the committee on anatomi-
cal nomenclature. Assoc. Amer. Anatomists, Records, 1889, p. 5.

Anatomical terminology. Reference Handbook of the Medical
Sciences. A. H. Buck. editor, VIII, 1889, pp. 515-537; 2 fig. Senior
author with S. H. Gage.

1890. Do the Barclayan terms cause obscurity? Letter to the editor.
Science, XV, 1890, p. 224.
The subfrontal gyre in man and apes. Address before the Alumni
Association of the Medical Department of the Niagara University,
18g0. See Buffalo Med. and Surg. Journal, XXIX, 1890, p. 648.

Remarks on the brain of Chauncey Wright, with commentaries
upon fissural diagrams. Amer. Neurol. Assoc. Trans., 1890. Jour.
Nerv. and Ment. Dis., XVII, 1890, pp. 753-754.

On the lack of the distance sense in the prairie-dog. Amer. Assoc.
Adv. Sci. Proc., XX XIV, 1890, p. 340; Science, Aug. 22, 1890.

Exhibition of diagrams of the brains and medisected heads of man
and achimpanzee. Amer. Asssoc. Adv. Sci. Proc., XX XIX, 1890,
pp. 375-376. Abstr. in Amer. Naturalist, XXIV, 1890, p. 980.

Exhibition of diagrams illustrating the formation of the human
Sylvian fissure. Amer. Assoc. Adv. Sci. Proc., XXXIX, 1890, pp.
346-347.

18g. Fundamental principles of anatomical nomenclature. Med.
News, Dec. 19, 1891, pp. 708-710.

The morphological importance of the membranous or other thin
portions of the encephalic cavities. Jour. Comp. Neurology, I, 1891,
pp. 201-203.

8 Scientific Publications

1893. Brain, gross or macroscopic anatomy. Reference Handbook of
the Medical Sciences, Supplement, A. H. Buck, editor, pp. 99-111;
Io fig. 1893.

Brain, methods of removing, preserving, dissecting and drawing.
Same. pp. IlI-121; 2 fig.

Meninges. (The envelopes or membranes of the brain and spinal
cord). Same. pp. 606-616; 11 fig.

Physiology Practicums : directions for examining the cat, and the

heart, eye, and brain of the sheep, as an aid in the study of element-

ary physiology. 8°. pp. 70; 27 plates. Ithaca, 1893.

Besides the publications recorded above Professor Wilder
has written many articles on natural history subjects for Har-
per’s Magazine, Atlantic Monthly, Galaxy, Our Young Folks,
the New York Tribune, etc. He has also written critical re-
views of many scientific works for The Nation and for scientific
periodicals.

TABLE SHOWING THE COURSES GIVEN BY PROFESSOR
WILDER, WITH THE NUMBER OF STUDENTS PERSON-
ALLY TAUGHT BY HIM’ DURING EACH COLLEGE YEAR
FROM THE BEGINNING OF THE UNIVERSITY, (1868), TO
THE TWENTY-FIFTH COMMENCEMENT, (1893).

COLLEGE 4 NEUROL- | LAB. & SPEC.
YEAR. ee EU OGY. LEcT. COURSES
1868-69 209 42
1869-70 230 74 64
1870-71 196 20 21
1871-72 175 36 : 14
1872-73 156 | 21 17
1873-74 147 133 37
1874-75 109 73 37
1875-76 144 77 20 47
1876-77 167 IOI 15 70
1877-78 57 II 55
1878-79 87 72 8 45
1879-80 97 80 16 63
1880-81 g2 64 16 103
1881-82 61 37 10 64
1882-83 49 50 4 35
1883-84 64 69 8 40
1884-85 53 42 8 66
1885-86 83 60 9 55
1886-87 130 42 9 14
1887-88 148 aT 15 27
1888-89 179 49 23 39
1889-90 170 41 22 40
1890-91 149 39 15 45
1891-92 147 36 23 18

| 1892-93 162 43 24 22

horas. 3261 | 99338 256 1038

It is shown by the above table that the total number of stu-
dents personally instructed by Professor Wilder in Physiology
during his 25 years in Cornell University is 3,261, in Zoology,
1,338, in Vertebrate Neurology 256, and the number in special
and laboratory courses was 1,038. As physiology is required
of all students working in the department of Physiology and

IO Courses Given by

Vertebrate Zoology, the number taking physiology represents
the total number of different students taught.

In zoology and neurology the totals represent different indi-
viduals, but as they had previously taken physiology they are
represented in the total for physiology. As special and labo-
ratory work extends throughout the year and may be taken
more than one year, the total in the last column represents
more or less duplication. Probably about 450 different stu-
dents have taken laboratory work, and special courses.

Since 1885-86 the courses in Anatomical and Microscopical
Methods, Histology and Embryology, while under the general
direction of Professor Wilder, were not personally conducted
by him, hence the students taking those courses are not in-
cluded in the table.

Under laboratory and special lecture courses, are in-
cluded lectures and laboratory work in comparative anat-
omy, collecting, preserving and mounting specimens, mu-
seum methods, systematic zoological work, practical anatomy,
embryology, vertebrate homologies, and philosophical anat-
omy.

From the beginning the general courses of Physiology and
Zoology have been abundantly illustrated by lecture-room
experiments and the exhibition of specimens and preparations
as well as by special demonstrations ; but in 1880-81 in Zoolo-
gy, and 1886-87 in Physiology, in addition to the experi-
ments and demonstrations given by Professor Wilder, he in-
troduced for these large and general classes practical labora-
tory work, or ‘‘ Practicums,’’ as he designated the work.
That is, two thirds of the time devoted to the study was given
to lectures and one third to the laboratory work in which
the students were trained in gaining knowledge by actual
personal investigation.

Until 1888-89 Physiology included also Hygiene, and Zoolo-
gy included both Vertebrates and Invertebrates until 1876-77.
Since that time Dr. Wilder’s course in zoology has been ex-
clusively vertebrate. In 1870-71 a course in ‘* Comparative
Neurology’ was given, but it was not until 1875-76 that
Vertebrate Neurology became an established course. It was
called by different names in different years, as ‘‘ comparative

Burt Green Wilder ET

anatomy of the nervous system of vertebrates,’’ ‘‘ compara-
tive anatomy of the brain,’’ and ‘‘ morphology of the brain.’’
It isin this course of neurology perhaps more than in any
other that is realized the picture drawn by Agassiz, in his
address at the inauguration of the university, of the teacher
going before his class with his own thoughts and as an elder
brother inspiring his pupils to the most enthusiastic and
earnest effort.

Pt

aye

‘

TEMPERATURE AND VERTEBRA—A STUDY IN
EVOLUTION.

BEING A DISCUSSION OF THE RELATIONS OF THE NUMBERS OF VERTE-
BRA AMONG FISHES, TO THE TEMPERATURE OF THE WATER AND TO
THE CHARACTER OF THE STRUGGLE FOR EXISTENCE.

By DAVID STARR JORDAN.

The present paper is an attempt to find a relation of cause
and effect in connection with the fact that in many groups of
fishes the species which live in the warmest water have the
fewest vertebree. As here given, it isa modified reprint, with
some additional matter, of a paper entitled ‘‘ Relations of
Temperature to Vertebree among Fishes,’’ published by the
author in Volume XIV of the Proceedings of the U. S.
National Museum for 1891, pages 107 to 120.

STATEMENT OF THE PROBLEM.

It has been known for many years that in certain groups of
fishes the northern or cold-water representatives have a larger
number of vertebree than those members which are found in
tropical regions. ‘To this generalization, first formulated by
Dr. Gill in 1863 and applied by him to the Ladrvidz, we may
add certain others which have been more or less fully appre-
ciated by ichthyologists, but which for the most part received
their first formal statement from the writer in 1891. In groups
containing fresh-water and marine members, the fresh-water
forms have in general more vertebre than those found in the
sea. The fishes inhabiting the depths of the sea have more
vertebree than their relatives living near the shore. In free-
swimming pelagic fishes the number of vertebrze is also great-
er than in the related shore fishes of the same regions. ‘The
fishes of the earlier geological periods have for the most part
numerous vertebre, and those fishes with the low numbers (24
to 26) found in the specialized spiny-rayed fishes appear only
in comparatively recent times. In the same connection we

14 David Starr Jordan

may also bear in mind the fact that those types of fishes (soft-
rayed and anacanthine) which are properly characterized by
increased numbers of vertebrae predominate in the fresh waters,
the deep seas, and in arctic and antarctic regions. On the
other hand the spiny-rayed* fishes are in the tropics largely in
the majority.

In this paper, I wish to consider these generalizations and
the extent to which eachistrue. I propose to refer all of them
to the same group of causes. In fact all of them may be com-
bined into one statement, that in general all other fishes have
a large number of vertebree as compared with the shore-fishes
of the tropics. The cause of the reduction in number of the
vertebree must therefore be sought in conditions peculiar to
the tropical seas. If in any case an increase in the number of

* For the purpose of the present discussion, we may regard the ordin-
ary fishes, exclusive of sharks, ganoids, eels, and other primitive or
aberrant types as forming three categories: (1) The soft-rayed or Phy-
sostomous fishes, with no true spines in the fins, with an open duct
to the air-bladder, the ventral fins abdominal (the pelvis being attached
only by the flesh and remote from the shoulder-girdle), cycloid scales,
etc. (2) The spiny-rayed or Acanthopterygian fishes, having usually
spines in the dorsal and other fins, no duct to the air-bladder, the skel-
ton firm, the ventrals attached by the pelvis to the shoulder-girdle, the
shoulder-girdle joined to the skull, and the scales usually ctenoid or
otherwise peculiar. The vertebrae among spiny-rayed fishes are larger,
and therefore generally fewer in number, and their appendages (shoul-
der-girdle, gill arches, ribs, interspinal bones, etc.,) are more specialized.
The spiny-rayed fishes are usually regarded as the most specialized or
‘highest’ in the scale of development. The question of whether, on
the whole, they are ‘‘ higher’’ or ‘‘ lower’’ as compared with sharks and
other primitive types is ambiguous, because various ideas are associated
with these words ‘‘high’’ and ‘“‘low.’’ It is certain, however, that the
spiny-rayed fishes deviate farthest from the primitive stock, and that the
qualities that distinguish fishes as a group are most intensified. In other
words, it isin the spiny-rayed fishes that the process of ‘‘ichthyization”’
or fish-forming has gone farthest. A third category would comprise the
Anacanthines (cods, flounders, etc.), fishes anatomically similar to the
spiny-rayed forms, but without spines to their fins, with weaker skele-
tons and smaller and more numerous vertebrae. They are ‘‘degenerate’’
or more ‘‘ generalized’’ offshoots from the spiny-rayed types, as the eels
are from some soft-rayed type.

Temperature and Vertebre 15

segments has come about through degeneration, the cause of
such degeneration must be sought for in the colder seas, in the
rivers and in the oceanic abysses. What have these in com-
mon that the sandy shores, rocky islands and coral reefs of the
tropics have not ?

STATEMENT OF THEORY.

For the purpose of this discussion we may assume the deri-
vation of species by means of the various influences and pro-
cesses, for which, without special analysis, we may use the
term ‘‘ natural selection.”’

By the influence of natural selection, the spiny-rayed fish,
so characteristic of the present geological era, has diverged
from its soft-rayed ancestry.

The influences which have produced the spiny-rayed fish
have been most active in the tropical seas. It is there that
‘“natural selection’’ is most potent, so far as fishes are con-
cerned. The influence of cold, darkness, monotony, and re-
striction is to limit the direct struggle for existence, and there-
fore to limit the resultant changes. In general the external
conditions most favorable to fish life are to be found in the
tropical seas, among rocks and along the coral reefs near the
shore. Here is the center of competition. From conditions
otherwise favorable to be found in arctic regions, the majority
of competitors are excluded by their inability to bear the cold.
In the tropics is found the greatest variety in surroundings,
aud therefore the greatest variety in the possible adjustments
of series of individuals to correspond with these surroundings.

The struggle for existence in the tropics is a struggle be-
tween fish and fish, and among the individuals of a very great
number of species each one acquiring its own peculiar points
of advantage. No form is excluded from competition. No
competitor is handicapped by loss of strength on account of
cold, darkness, foul water, or any condition adverse to fish
life. Very few fishes are excluded from the tropical seas by
the heat of the water. The land heat of the tropics is often
unfavorable to life and especially to activity. But in the sea
the temperature is never unfavorable to self activity. The
water is never sultry, nor laden with malaria.

16 David Starr Jordan

The influences which serve as a whole to make a fish more
intensely and compactly a fish, and which tend to rid it of
every character and every organ not needed in fish life, should
be most effective along the rocks and shores of the tropics

For this process of intensification of fish-like characters,
which finds its culmination in certain specialized spiny rayed*
fishes of the coral reefs, we may conveniently use the term
“* Ichthyization ’?

If ‘‘ichthyization’’ is in some degree a result of conditions
found in the tropics, we may expect to find a less degree of
specialization in the restricted and often unfavorable condi-
tions which prevail in the fresh waters, in the cold and exclu-
sion of the polar seas, and especially in the monotony, dark-
ness, and cold of the oceanic abysses where light cannot pen-
etrate and where the temperature scarcely rises above the
freezing point.

An important factor in ‘“‘ichthyization’’ is the reduction of
the number of segments or vertebree, and a proportionate in-
crease in the size and complexity of the individual segment
and its appendages.

If the causes producing this change are still in operation, we
should naturally expect that in cold water, deep water, dark
water, the fresh waters, and in the waters of a past geologi-
cal epoch the process would be less complete and the numbers
of vertebrze would be larger, while the individual vertebre re-
main smaller, less specialized and often imperfectly ossified.
And this, in a general way, is precisely what we find in the
examination of skeletons of a large series of fishes.

If this view is correct, we have a possible theory of the re-
duction in numbers of vertebreze as we approach the equator.
It should, moreover, not surprise us to encounter various
modifications and exceptions, for we know little of the hab-
its and scarcely anything of the past history of great numbers
of species. ‘The present characters of species may depend on
occurrences in the past concerning which even guesses are
impossible.

‘

* The Parrot-fishes (Scarid@), Trigger-fishes (Balistide), Angel-fishes
(Chetodontide), etc.

Temperature and Vertebre 17

In considering the increase in number and corresponding
reduction in size of the vertebree of northern fishes, it is often
very difficult to distinguish between primitive simplicity, such
as the salmon and herring show, and the lack of complexity
which may be due to ‘‘ Panmixia’’ or the cessation of selec-
tion—examples of which may be found in the Lizparidide and
perhaps in the cod and arctic blennies.

We have also, in connection with the process of ichthyiza-
tion, something of what Professor Dana calls ‘‘ Cephalzzation.”’
Features of this are (1) the attachment of the shoulder-girdle
to the skull, which occurs in most recent fishes, but which is
carried to co-ossification in the case of some of the most spe-
cialized, (Balistide, Tetrodontide, etc.). (2) The attachment
of the pelvis to the shoulder-girdle or to the head, shown in
the spiny-rayed fishes and their allies, and (3) the modification
and specialization of various bones of the jaws and gill arches,
which is in the most specialized forms often accompanied by
co-ossification or by reduction in number of the bones con-
cerned. Connected with these changes is the gradual reduc-
tion or loss of the air-bladder, which is a degenerate lung,
doubtless used for air-breathing by the ganoid ancestors of
the modern fishes. In the spiny-rayed fishes it is a closed
sac, often so small as to be functionless and very often it is
wholly absent.

NUMBERS OF VERTEBR.

We may now consider in detail the numbers of the vertebre
in the different groups of fishes :

Lancelets.—In the different species of Bvanchiostoma or
lancelet, a group which stands at the bottom of the vertebrate
series, probably diverging from the fish-stock before the
formation of a brain or organs of special sense, the number
of segments is large, from 50 to 80.

Lampreys.—In the lampreys and hag-fishes, low and to
some extent primitive types, which show no trace of limbs
or jaws, the vertebree are cartilaginous and numerous, being
little specialized. The number in species examined is more
than a hundred, the range being perhaps from 100 to I50.

18 David Starr Jordan

The fin rays of the vertical fins are little developed and very
numerous, both being primitive characters.

The Sharks.—The sharks and skates show likewise a
very large number of vertebrae, 120 to 150 in the species in
which they have been counted. In these fishes no compara-
tive study of the vertebree has been made. ‘The group isa
very ancient one in geological time, and in the comparatively
few remaining members of the group, the vertebree, in fact
the entire skeleton, is in a very primitive condition, the ver-
tebree being cartilaginous, the fin rays slender and very nu-
merous, not provided with separate interspinal bones. The
sharks are free-swimming fishes, and with them as with the
eels, flexibility of body is essential to the life they lead.

One of the living sharks, Chlamydoselachus, said to be the
oldest living type of vertebrate, has the body greatly elon-
gate, fairly eel-shaped, and it doubtless has a maximum num-
ber of vertebree. A large number of cartilaginous vertebree
is also found in the group of Chimeras, aud in the Dipnoi, a
very ancient type allied to the ganoids, and doubtless the
parent stock of the batrachians and through these of the

reptiles, birds, and mammals. Among the batrachians a
reduction in the number of vertebrze is associated with the

abandonment of aquatic life.

Ganoid Fishes.—It may be taken for granted that the an-
cestry of the various modern types of bony fishes is to be
sought among the ganoids. All the fossil forms in this
group have a notably large number of vertebree. The few
now living are nearly all fresh-water fishes, and among these,
so far as known, the numbers range from 65 to 110.*

Soft-rayed Fishes.—Among the TZeleosted or bony fishes,
those which first appear in geological history are the /sospon-
dyli, the allies of the salmon and herring. These have all
numerous vertebree, small in size, and none of them in any
notable degree modified + or specialized. In the northern
seas Jsospondyli still exceed all other fishes in number of

* Sixty-seven in Polypterus, 110 in Calamoichthys, 95 in Ama, ete.
+ As is indicated by the name Jsospondyli, from tos, equal, orov-
dvAos, vertebra.

Temperature and Vertebre 19

individuals. They abound in the depths of the ocean, but
there are comparatively few of them in the tropics.

The Salmonide* which inhabit the rivers and lakes of the

northern zones have from 60 to 65 vertebree. The Scopelide,
Stomiatide, and other deep-sea analogues have from 4o up-
wards to perhaps 100, in the few species in which the number
has been counted. In these the weakness of the skeleton and
the frequent disconnection of the shoulder girdle from the
head seem to be features of degradation.
_ The group of Clupezde t is probably nearer the primitive
stock of /sospondyli than the salmon are. ‘This group is es-
sentially northern in its distribution, but a considerable num-
ber of its members are found within the tropics. The com-
mon herring | ranges farther into the arctic regions than any
other. Its vertebrze are 56 in number. In the shad,§ a
northern species which ascends the rivers, the same number
has been recorded.

The sprat|| and sardine#] ranging farther south, have
from 48 to 50, while in certain small herring ** which are
strictly confined to tropical shores the number is but 4o.

Allied to the herring are the anchovies, mostly tropical.
The northernmost species, tt the common anchovy of Europe,
has 46 vertebree. A similar species in the temperate Pacific
(Stolephorus mordax) has 44. A tropical species {{ has 41
segments.

There are, however, a few soft-rayed fishes §§ confined to
the tropical seas in which the numbers of vertebrze are still:
large, an exception to the general rule for which there is no
evident reason unless it be connected with the wide distribu-
tion of these almost cosmopolitan fishes, which may have had:
pelagic ancestors.

* Salmon, trout, grayling, whitefish, etc.

+ Herring, shad, sprat, sardine, and their allies.

{t Clupea harengus. 2 Clupea alosa, the European shad.

|| Clupea sprattus. | Clupea pilchardus.

** Harengula macrophthaima. +} Engranlis enchrasicolus.

tt Stolephorus brownt.

22 Among these are Albula vulpes, the bonefish, with 70 vertebre,
Llops saurus, the ten-pounder, with 72, the Grande Ecaille (Megalops)
with 57, and Chanos chanos with 72.

20 David Starr Jordan

In a fossil herring-like fish from the Green River shales, I
count 40 vertebree ; in a bass-like or serranoid fish from the
same locality 24, these being the usual numbers in the
present tropical members of these groups.

The Plectospondyli are those soft-rayed fishes in which the
four anterior vertebree are highly modified, co-ossified and
having a peculiar relation to the organ of hearing. The
Stluride, Cyprinide, Catostomide, Characinide, Gymnotide,
and Llectrophoride with their relatives belong here. ‘This
peculiar structure of the vertebree is found in no other group.
It could hardly have arisen independently in the different
families, hence these great groups including the vast majority
of fresh-water fishes must be referred to a common stock.

The great family of Sz/urzde@ or catfishes seems to be not
allied to the /sospondyli, but a separate offshoot from another
ganoid type allied to the sturgeons. This group is repre-
sented in all the fresh waters of temperate and tropical
America, as well as in the warmer parts of the Old World.
One division of the family, containing numerous species,
abounds on the sandy shores of the tropical seas. The
others are all fresh-water fishes. So far as the vertebre in
the Szluride have been examined, no conclusions can be
drawn. ‘The vertebre in the marine species range from 35*
to 50; in the North American forms from 37 to 45,} and in
the South American fresh-water species, where there is al-
most every imaginable variation in form and structure, the
numbers range from 28 to 50 or more.

The Cyprinide,} also belonging to the group of Plectospon-
dyli, confined to the fresh waters of the northern hemisphere,
and their analogues, the Characinide of the rivers of South
America and Africa, have also numerous vertebree, 36 to 50
in most cases. I fail to detect in either group any relation in
these numbers to surrounding conditions. The related Gym-

notide and Electrophoride of the tropical rivers have many
vertebree.

* Tachysurus, Felichthys, etc.
t Lctalurus, Ameiurus, ete.
{ Carp, minnows, suckers, chubs, buffalo-fishes, gudgeons, etc.

Temperature and Vertebre 21

In general, we may say of the soft-rayed fishes that very
few of them are inhabitants of tropical shores. Of these few,
some, which are closely related to northern forms, have
fewer vertebree than their cold-water analogues. In the
northern species, the fresh-water species and the species found
in the deep sea, the number of vertebrze is always large, but
the same is true of some of the tropical species also.

Spiny-rayed Fishes.—Among the spiny-rayed fishes, the
facts are more striking. Of these, numerous familes are
chiefly or wholly confined to the tropics, and in the great
majority of all the species the number of vertebree is con-
stantly 24,* 10 in the body and 14 in the tail (10414).

In some families in which the process of ichthyization has
gone on to an extreme degree, as in certain plectognath
fishes,f there has been a still further reduction, the lowest
number, 14, existing in the short inflexible body of the
trunkfish,{ in which the vertebral joints are movable only in
the base of the tail. In all these forms, the process of reduc-
tion of vertebree has been accompanied by specialization in

* This is true of all or nearly all the Serranide, Sparide, Scienide,
Chetodontide, Hemulide, Gerride, Gobiide, Acanthuride, Mugt-
lide, Sphyrenide, Mullide, Pomacentride, etc.

{ Balistes, the trigger fish, 17; Monacanthus and Alutera, foolfishes,
about 20; the trunkfish, Ostracion, 14; the puffers, 7Zetraodon and
Spheroides, 18; Canthigaster, 17; and the headfish, M/o/a, 17. Among
the Pediculates, Malthe and Antennarius have 17 to 19 vertebree, while
in their near relatives, the anglers, Lophiid@, the number varies with the
latitude. Thus, in the northern angler, Lophius piscatorius, which is
never found south of Cape Hatteras, there are 30 vertebree, while in a simi-
lar species, inhabiting both shores of the tropical Pacific, Lophiomus seti-
gerus, the vertebre are but 19. Yet, in external appearance, these two
fishes are almost identical. It is, however, a notable fact that some of
the deep-water Pediculates, or angling fishes, have the body very short
and the number of vertebre correspondingly reduced. Dibranchus
atlanticus, from a depth of 3,600 fathoms, or more than 4 miles, has
but 18 vertebre, and others of its relatives in deep waters show also
small numbers. These soft-bodied fishes are simply animated mouths,
with a feeble osseous structure, and they are perhaps recent offshoots
from some stock which has extended its range from muddy bottom or
from floating seaweed to the depths of the sea,

{ Ostracion.

22 David Starr Jordan

other respects. ‘The range of distribution of these fishes is
chiefly though not quite wholly confined to the tropics.

A very few spiny-rayed families are wholly confined to the
northern seas. One of the most notable of these is the family
of viviparous surf fishes, * of which numerous species abound
on the coasts of California extending to Oregon, and Japan,
but which enter neither the waters of the frigid nor the torrid
zone. ‘These fishes seem to be remotely connected with the
Labride+ of the tropics, but no immediate proofs of their
origin exist. The surf fishes have from 32 to 42 vertebre,
numbers which are never found among tropical fishes of simi-
lar appearance or relationship.

The fact of variation in the numbers of vetebrze was first
noticed among the Ladride. Here the facts are most strik-
ing. Inthe genera of Ladbride inhabiting northern Europe
and the New England waters (Labrus, Acantholabrus, Ctenola-
brus, Tautoga,) there are 38 to 41 vertebree, in the Mediter-
ranean forms (Symphodus, etc.,) 30 to 33, in certain semi-
tropical genera (Lachnolaimus, Harpe, Trochocopus) 27 to 29,
while in those genera which chiefly abound about the coral
reefs (Scarus, Sparisoma, Xyrichthys, Julis, Thalassoma, Fal-
tcheres) the number is from 23 to 25.

Equally striking are the facts in the great group of Ca/aph-
ractt, or mailed-cheek fishes, a tribe now divided into several
families, diverging from each other in various respects, but
agreeing in certain peculiarities of the skeleton.t

Among these fishes the family most nearly related to ordi-
nary fishes is that of the Scorpenide.§

This is a large family containing many species, fishes of
local habits, swarming about the rocks at moderate depths in
all zones. ‘The species of the tropical genera have all 24 ver-
tebree.|| Those genera chiefly found in cooler waters, as in

* Embiotocide.

+ Wrasse fishes, old wives, parrot fishes, cunners, tautogs, redfishes,
sefioritas, etc.

t Notably by the formation of a bony ‘‘stay’’ to the preopercle by
the backward extension of one of the suborbital bones.

2 Sea scorpions, rockfishes, ‘‘ rock cod,’’ rosefishes, etc.

|| Scorpena, Sebastoplus, Pterois, Synanceia, Synancidium, etc.

Temperature and Vertebre 23

California,* Japan, Chili, and the Cape of Good Hope, have
in all their species 27 vertebrze, while in the single arctic
genus there are 31. An antarctic genus{ bearing some
relation to Sebastes has 39.

Allied to the Scorpenide, but confined to the tropical or
semi-tropical seas, are the Platycephalide, with 27 vertebre,
and the Cephalacanthide with but 22. In the deeper waters
of the tropics are the Peristediid@, with 33 vertebrae, and ex-
tending farther north, belonging as much to the temperate as
to the torrid zone, is the large family of the 7rviglde,§ in
which the vertebree range from 25 to 38.

The family of Agonidz,|| with 36 to 40 vertebre, is still
more decidedly northern inits distribution. Wholly confined
to northern waters is the great family of the Coftédz,4 in
which the vertebre ascend from 30 to 50. Entirely polar and
often in deep waters are the Lipariaide,** an offshoot from
the Cottide, with soft, limp bodies, and the vertebrze 35 to 65.
In these northern forms there are no scales, the spines in the
fins have practically disappeared, and only the anatomy shows
that they belong to the group of spiny-rayed fishes. In the
Cyclopteride, ++ likewise largely arctic, the body becomes short
and thick, the backbone inflexible, and the vertebrze are again
reduced to 28. In most cases, as the number of vertebree in-
creases, the body becomes proportionally elongate. As a
result of this, the fishes of arctic waters are, for the most part,
long and slender, and not a few of them approach the form of
eels. In the tropics, however, while elongate fishes are com-
mon enough, most of them (always excepting the eels) have
the normal number of vertebrze, the greater length being due

* Sebastichthys and its offshoots Sebastodes, Sebastopsis, etc., the
“‘rock cod ”’ of California. + The rosefish, Sedasfes and its offshoot,
the genus or subgenus, Sebastolobus. t Agriopus

2 The gurnards and sea robins. The lowest numbers are found in the
American genus Prionotus, which is chiefly tropical, the highest in
Lepidotrigla, which is confined to southern Europe.
|| Sea poachers, alligator fishes, etc. Sculpins, Miller’s thumbs, etc.
** Sea snails. tt Lumpfishes,

24 David Starr Jordan

to the elongation* of their individual vertebrae and not to
their increase in number.

In the great group of blenny-like fishes the facts are equally
striking. The arctic species are very slender in form as com-
pared with the tropical blennies, and this fact, caused by a
great increase in the number of their vertebrze, has led to the
separation ofthe group intoseveral families. The tropical forms
composing the family of Blexniide + have from 28 to 49 verte-
bree, while in the arctic genera the numbers range from 75 to 100.

The anacanthine fishes in whole or in part seem to have
sprung from a blennioid stock. Of these the most specialized
group is that of the flounders,t below described. The
wide distribution of this family, its members being found on
the sandy shores of all zones, renders it especially important
in the present discussion. ‘The other anacanthine families are
chiefly confined to the cold waters or to the depths of the seas.

In the cod family § (Gadde) the number of vertebrze is
usually about 50, and in their deep-sea allies, the grenadiers]|
or rat-tails, the numbers range from 65 to 8o.

* Thus the very slender goby, Godzus oceanicus has the same number
(25) of vertebree as its thick-set relative Gobius soporator or the chubby
Lophogobius cyprinoides.

{Of the true Blennizid@, which are all tropical or semi-tropical,
Blennius has 28 to 35 vertebrae; Salarias, 35 to 38; Labrosomus, 34;
Clinus, 49; Cristiceps, 40. A fresh water species of Cristiceps found in
Australia has 46. Blennioid fishes in the Arctic seas are Anarrhichas,
with 76 vertebree ; Anarrhichthys, with too or more; Lumpenus, 79;
Murenoides, 85; Lycodes, t12; Gymnelis, 93. Lycodes and Gymnelis
have lost all the dorsal spines and are intermediate between the blennies
and the forms called Anacanthine. The gradual degeneration of such
northern forms may perhaps be attributed to the influence of ‘‘ Pan-
mixia’’ or the cessation of selection. : tPleuronectide.

2 Fifty-one in the codfish (Gadus callarias,) 58 in the Siberian cod
(Eleginus navaga) 54 in the haddock (Melanogrammus eglifinus) 54
in the whiting (Werlangus merlangus), 54 in the coal-fish (Pollachtus
virens) 52 in the Alaskan coal-fish (follachius chalcogrammus), 51 in
the hake (Werluccius merluccius). Inthe burbot (Lota /ota) the only
fresh water codfish, 59; in the deep water ling (J7olva molva), 64; in
the rocklings (Gaidropsarus) 47 to 49. ‘Those few species found in the
Mediterranean and the Gulf of Mexico have fewer fin rays and prob-
ably fewer vertebree than the others, but none of the family enter warm
water, the southern species living at greater depths. || Macruride.

Temperature and Vertebre 25

In the family of flounders or Pleuronectide, a group of
wide distribution and in which the individual vertebree are
numerous and little specialized the results are especially strik-
ing.

In each of the four principal groups, the numbers agree
closely with the geographical distribution of the different
genera. Thus in the comparatively primitive subfamily of
fTippoglossine, the halibut group, the division nearest the
cod-like stock from which the flounders are probably de-
scended, the numbers range from 35 to 50. In the turbot
group (Psettiéne) from 31 to 43. In the plaice group, (Pleu-
vonectine) 35 to 65. In the sole group, (Soleime) 28 to 49.
The tongue-fishes (Cynoglossine) are elongate like the eels,
and specialized in analogous ways. Although all tropical,
the numbers counted range from 47 to 52.*

fresh Water Fishes. —Of the families confined strictly to the
fresh waters the great majority are among the soft-rayed or

*These facts may be shown in tabular form as follows :

HIPPOGLOSSIN 4.

Flippoglossus, 50, Arctic. Psettichthys, 40, Subarctic.
Atheresthes, 49, Arctic. FParalichthys, 35 to 41, Temperate
Hippoglossoides, 45, Subarctic. and Semitropical.
Lyopsetta, 45, Subarctic. Xystreurys, 37, Semitropical.
Eopsetta, 43, Subarctic. Ancylopsetta, 35, Semitropical.

PSETTIN &. PLEURONECTINA.
Monolene, 43, Deep Sea. Glyptocephalus, 58 to 65,
Lepidorhombus, 41, Arctic. Arctic and deep sea.
Orchopsetta, 40, Subarctic. Microstomus, 48 to 52,
Platophrys, 37 to 39, Tropical. Arctic and deep sea.
Arnoglossus, 38, Semitropical. Farophrys, 44, Subarctic.
Zeugopterus, 37, Temperate. Pleuronectes, 43, Subartctic.
Bothus, 36 Temperate. Isopsetta, 42, Subarctic.
Syacium, 35 to 36, Tropical. Lepidopsetta, 40, Subarctic.

Citharichthys, 34 to 36, Tropical. Limanda, 40, Subarctic.
Phrynorhombus, 35, Semitropical. Lzopsetta, 40 Subarctic.

Etropus, 34, Tropical. Pleuronichthys, 38 to 40,
Zev1a, 33, Tropical. Temperate.
Psetta, 31, Vropical. Flesus, 36, Temperate.
Pseudopleuronectes, 36,
Temperare.

Flypsopsetta, 35, Semitropical.
Platichthys, 35, Subarctic.

26 David Starr Jordan

physostomous fishes, the allies of the salmon,* pike, carp, and
cat-fish. In all of these the vertebrze are numerous. A few
fresh water families have their affinities entirely with the more
specialized forms of the tropicalseas. Of these the Centrarchi-
d@ (comprising the American fresh-water sun-fish} and black
bass [) have on the average about 30 vertebree, the pirate
perch § 29, and the perch || family, perch and darters, etc., 35
to 45, while the Servvanide or sea bass, the nearest marine rel-
atives of all these, have constantly 24. The iarine family of
demoiselles§] have 26 vertebre, while 30 to 4o vertebra
usually exist in their fresh-water analogues (or possibly de-
scendants), the Czchlide, of the rivers of South America and
Africa. The sticklebacks,** a family of spiny fishes, confined
to the rivers and seas of the north, have from 31 vertebree to
41. The Ophiocephalide, Anabantide and other old world
families of fresh water fishes have more vertebre than their
marine analogues. No fresh water fishes (except a few Sczent-
d@,t+ which have come comparatively recently into fresh
waters) have the number of vertebra as low as 24, the usual
number in the spiny-rayed shore fishes of the tropics.

Pelagic Fishes.—It is apparently true that among the free
swimming, or migratory pelagic fishes, the number of verte-
bre is greater than among their relatives of local habits.
This fact is most evident among the scombriform fishes, the
allies of the mackerel and tunny. All of these belong prop-
erly to the warm seas, and the reduction of the vertebree in
certain forms has no evident relation to the temperature,
though it seems to be related in some degree to the habits
of the species. Perhaps the retention of many segments is
connected with that strength and swiftness in the water for
which the mackerels are preeminent.

The variations in the number of vertebrze in this group led
Dr. Giinther, nearly 30 years ago, to divide it into two
families, the Cavangide and Scombride.

* Cyprinide, Salmonidw, Esocide, Characinide, Cyprinodontide,
Silurid@, etc.

+ Lepomis. | Pomacentride. || Percide.

2 Aphredoderide. + Micropterus. ** Gasterostetd@.
tt Aplodinotus Plagioscion Pachyurus, etc.

Temperature and Vertebre 27.

The Carangide* are tropical shore fishes, local or migratory
toaslight degree. All these have from 24 to 26 vertebree.
In their pelagic relatives, the dolphins,} there are from 30 to
33; in the opahs,t 45; in the Brama, 42; while the great
mackerel family,§ all of whose members are more or less
pelagic, have from 31 to 50.

Other mackerel-like fishes are the cutlass|| fishes, which
approach the eels in form and in the reduction of the fins.
In these the vertebrae are correspondingly numerous, the
numbers ranging from 100 to 160.

In apparent contradistinction to this rule, however, the
pelagic family of swordfishes,4] remotely allied to the mack-
erels, and with even greater powers of swimming, has the
vertebrze in normal number, the common swordfish having
but 24.

The Eels. —The eels constitute a peculiar group of uncertain,
but probably soft-rayed, ancestry, in which everything else has
been subordinated to muscularity and flexibility of body. The
fins, girdles, gill arches, scales, and membrane bones are all
imperfectly developed or wanting. The eel is perhaps as far
from the primitive stock as the most highly ‘“achthyized’’
fishes, but its progress has been of another character. The
eel would be regarded in the ordinary sense as a degenerate
type, for its bony structure is greatly simplified as compared
with its ancestral forms, but in its eel-like qualities it is, how-
ever, greatly specialized. All the eels have vertebrae in great
numbers. As the great majority of the species are tropical,
and as the vertebree in very few of the deep-sea forms have
been counted, no conclusions can be drawn as to the relation
of their vertebree to the temperature.

*Pampanos, amber fishes, pilot fishes, cavallas, etc.

| Coryphena. t Lampris.

2 Scombridw. The mackerel (Scomber scombrus, has 31 vertebree ;
the chub mackerel (Scomber colias), 31; the tunny (Adbacora thynnus),
39 ; the long-finned albacore (AJlbacora alalonga), 40; the bonito (Sarda
sarda), 50; the Spanish mackerel (.Scomberomorus maculatus), 45:

\| Trichiuride : Aphanopus, 101 vertebrae; Lepidopus, 112; Tr-
churus, 159.

{ Xiphiide.

28 David Starr Jordan

It is evident that the two families most decidedly tropical
in their distribution, the morays* and the snake eels, have
diverged farthest from the primitive stock. They are most
‘“‘degenerate,’’ as shown by the reduction of their skeleton.
At the same time they are also most decidedly ‘‘ eel-like,”’
and in some respects, as in coloration, dentition, muscular de-
velopment, most highly specialized. It is evident that the
presence of numerous vertebral joints is essential to the sup-
pleness of body which is the eel’s chief source of power.

So far as known the numbers of vertebree in eels range from
I15 to 225, some of the deep-sea eels{ having probably higher
numbers, if we can draw inferences from their slender or
whip-like forms ; but this character may be elusive.

VARIATIONS IN FIN-RAYS.

In some families the number of rays in the dorsal and anal
fins is dependent on the number of vertebrae. It is therefore
subject to the same fluctuations.§ This relation is not
strictly proportionate, for often a variable number of rays
with their interspinal processes will be interposed between a
pair of vertebree. ‘Ihe myotomes or muscular bands on the
sides are usually coincident with the number of vertebree.
As, however, these and other characters are dependent on
differences in vertebral segmentation, they bear the same rela-
tions to temperature that the vertebrze themselves sustain.

* Murenide. Among the morays, Murena helena has 140;
Gymnothorax meleagris, 120; G. undulatus, 130; G.moringa, 145;
G. concolor, 136,; Echidna catenata, 116, E.-nebulosa, 142; EF. zebra,
135. In other families the true eel, duguilla anguilla, has 115; the
Conger eel, Leptocephalus conger, 156; Mureenesox cinereus, 154;
M. coniceps, 154; Ophichthys ocellatus, 134; O. gomesi, 141 ; Syna-
phobranchus pinnatus, 146 ; Gordiichthys irretitus, 225.

ft Ophisuride.

t Nemichthys, Nettastoma, Venefica.

2 Thus in the Scorpenide, Sebastes, the arctic genus has the dorsal
rays XV, 13, the vertebree 12 +19. Thetropical genera Scorpena and
Sebastoplus have the dorsal rays XJ, 10, the vertebrae 10-+ 14, while the
semitropical genus Sebastodes has the intermediate numbers of dorsal
rays XII, 12, and vertebree 12+ 15.

Temperature and Vertebre 29

CONCLUSION.

From the foregoing examples we may conclude that, other
things being equal, the numbers of vertebree are lowest in
the shore-fishes of the tropics, and especially in those of local
habits, living about rocks and coral reefs.

The cause of this is to be found in the fact that in these lo-
calities the influences of natural selection are most active.
The reduction of vertebrae may be regarded as a phase in the
process of specialization which has brought about the typical
spiny-rayed fish.

These influences are most active in the warm, clear waters
of tropical shores, because these regions offer conditions most
favorable to fish life, and to the life of the greatest variety of
fishes. No fish is excluded from competition. There is the
greatest variety of competitors, the greatest variety of fish-
food, and the greatest variety of conditions to which adapta-
tion is possible. The number of species visiting any single
area is vastly greater in the tropics than in cold regions.

A single drawing of the net on the shores of Cuba* will
obtain more different kinds of fish than can be found on the
coasts of Maine in a year. Cold, monotony, darkness, isola-
tion, foul water; all these are characters opposed to the
formation of variety in fish life. The absence of these is a
chief feature of life in the tropical waters.

The life of the tropics, so far as the fishes are concerned,
offers analogies to the life of cities, viewed from the stand-
point of human development. In the same way the other re-
gions under consideration are, if we may so speak, a sort of
ichthyological backwoods. In the cities, in general, the con-
ditions of individual existence are most easy, but the compe-
tition is most severe. The struggle for existence is not a
struggle with the forces and conditions of nature. It is not a
struggle with wild beasts, unbroken forests, or a stubborn
soil, but a competition between man and man for the oppor-
tunity of living.

* In 1884 a single haul of a net in a shallow bay on Key West brought
in seventy-five species of shore-fishes. A week’s work about Martha’s
Vineyard yielded but forty-eight kinds.

30 David Starr Jordan

It is in the cities where the influences which tend to the
modernization and concentration of the characters of the spe-
cies, that the intensification of human powers and their adap-
tation to the various special conditions go on most rapidly.
That this intensification is not necessarily progress either
physical or moral is aside from our present purpose.

It is in the cities where those characters and qualities not
directly useful in the struggle for existence are first lost or
atrophied.

Conversely it is in the ‘‘backwoods,’’ the region most
distinct from human conflicts, where primitive customs, an-
tiquated peculiarities, and useless traits are longest and most
persistently retained. The life of the backwoods will be not
less active and vigorous, but it will lack specialization.

It is not well to push this analogy too far, but we may per-
haps find in it a suggestion as to the development of the eels.
In every city there is a class which partakes in no degree of
the general line of development. Its members are specialized
in a wholly different way, thereby taking to themselves a field
which the others have abandoned, and making up in low cun-
ning what they lack in strength and intelligence.

Thus among the fishes we have in the regions of closest
competition a degenerate and non-ichthyized form, lurking in
holes among rocks and creeping in the sand, thieves and
scavengers among fishes.

The eels fill a place which would otherwise be left unfilled.
In their way, they are perfectly adapted to the lives they
lead. A multiplicity of vertebral joints is useless to the
typical fish, but to the eel strength and suppleness are every-
thing, and no armature of fin or scale or bone so desirable as
its power of escaping through the smallest opening.

It may be too that, as rovers in the open sea, the strong,
swift members of the mackerel family find a positive advan-
tage in the possession of many vertebree, and that to some
adaptation to their mode of life we must attribute their lack
of ‘‘ichthyization’’ of the skeleton. But this is wholly hypo-
thetical, and we may leave the subject with the general con-
clusion that with the typical fish advance in structure has

y

Temperature and Vertebre af

specialized the vertebrze, increased their size and the com-
plexity of their appendages, while decreasing their number.
That with some exceptions and modifications this reduction
is characteristic of fishes in the tropics, and that it is so be-
cause in the tropics the processes of evolution are most active,
so far as the fishes are concerned.

UNEXPECTED VARIABILITY IN THE NUMBER OF SEGMENTS.

The most surprising feature in the present investigation is
that the number of segments in the adult animal should be
determined so late in the process of evolution and that it
should be So easily affected by the reaction from differences
in external conditions. There are several cases of species al-
most alike in external characters, differing one from the other
in the number of vertebrae, this difference being associated
with the distance of the range of the species from the tropics.
There are numerous cases in which such marked differences
distinguish species which no one would think of placing in
different genera (in Szphostoma, for example).

In other cases (Sebastes, Sebastodes and Sebastoplus - Lo-
phius and Lophiomus) genera commonly recognized are dis-
tinguishable only by their numbers of vertebree. ‘This fact
shows that the character in question is a recent one, arising
after all general matters of form, coloration and appearance
have become fixed. That the less number of vertebrze might
characterize tropical families as a whole as compared with
less specialized extra-tropical groups is not strange. That its
influence should be felt within the range of almost every
widely distributed family or even genus, and in some cases
even within the limits of a species, is certainly surprising.

MATTERS FOR FURTHER INVESTIGATION.

This matter has been thus far studied only in the skeletons
of adult fishes. It should be extended to their embryology,
that we may find out whether in fishes with 24 vertebre a
larger number is present in the young. If so, we should
know by what process the segments disappear.

ge David Starr Jordan

We should know also in each group which are the ancestral
or primitive forms. We should know whether the arctic
members of any group are those primitively of many segments,
or whether their characters are due to degradation through
‘‘Panmixia,’’ or from other cause. This investigation should
be extended to each group, and the answers in different
groups may be different.

The analogy of the reduction in number and the specializa-
tion of the individual vertebree and fin-rays, to the reduction
and specialization of wing-veins in Lepidoptera, as shown by
Professor Comstock should be studied. ‘The resemblance of
the results of evolution in Fishes and Insects indicate a like-
ness in the causes.

The correlated changes in the brain and nervous system
should also be studied. Mr. Frank Cramer has suggested to
me that the process of ‘‘Ichthyization’’ should have given
tropical forms larger and more specialized cephalic ganglia.
To this end, the size and form of brain in Sebastes, Sebastodes
and Scorpena should be carefully studied. Similar studies in
the Labride, Pleuronectide, Blenniide and Lophitde ought to
yield interesting results.

It will be also interesting to know whether any analogous
changes have taken place in any other groups of animals as
Snakes, Lizards, Batrachians, Crabs, Centipedes or Insects.
But among land-animals it will not be surprising if the results
are different for the conditions are not quite parallel. With
fishes the greatest tropical heat of sea-water is never too
great for comfort, nor is it often greater than the natural
temperature of the fish. The heat of the land is often much
greater than this and it may be so great as to interfere with
individual growth of land animals, and it may thus check
competition instead of stimulating it.

In any event, a comparative study of the relations of seg-
ments to temperature in any group cannot fail to yield inter-
esting results.

HISTORICAL SKETCH.

Ginther, 1862.—The earliest observation on record in refer-
ence to the subject in question was made by Dr. Albert Gtn-

Temperature and Vertebre 33

ther. He noted that among the Ladrvide, the species of
temperate waters had more vertebre than those of the tropics.
He says :*

In those genera of Labrid@ which are composed entirely or for the
greater part of tropical species the vertebral column is composed of
twenty-four vertebree, whilst those which are chiefly confined to the
temperate seas of the northern and southern hemispheres have that
number increased in the abdominal and caudal portions,

Gill, 1863.—Shortly after, in a review of Dr. Gitinther’s
work on the Labroids,+ Dr. Theodore Gill showed that this
generalization was not confined to the labroids alone, but
that ‘‘it may also be extended to other families. * * * This
generalization is applicable to the representatives of acan-
thopterygian} families generally, and can be considered in
connection with the predominance of true malacopterygian§
fishes in northern waters, fishes in which the increase in the
number of vertebrze is a normal feature.’’

Gill, 1864.—Later,|| Dr. Gill remarked that the increase in
the number of vertebrze of Sedastes, a genus peculiar to the
northern seas, affords an excellent example of the truth of the
generalization claiming an increased number of vertebrz for
the cold-water representatives of acanthopterygians.

Jordan, 1886.—In 1886, in a paper before the Indiana Acad-
emy of Sciences,4]/ the present writer showed that in very
many families the number of veterbree decreases as we ap-
proach the tropics. So constant is this relation that it was
thought that it might almost be termed alaw. ‘The writer
could however suggest no adequate cause by the operation of
which such changes are brought about.

Jordan and Goss, 1889.—In a study of the flounders, in
1889,*** a table was given showing the numbers of vertebree in

* Catalogue of the Fishes of the British Museum, vol. Iv, p. 65.

f On the Labroids of the Western Coast of North America, Proc. Ac.
Nat. Sc., Phila., 1863, p. 221.

t Spiny-rayed.

¢ Soft-rayed ; here including the anacanthine fishes.

|| Proceedings Academy Natural Science, Phila., 1864, 147.

4 Still unpublished.

** A Review of the Flounders and Soles (Pleuronectide) of America
and Enrope, by David S. Jordan and David K. Goss.

34 David Starr Jordan

the different species. From this table it was made evident
that in that group of founders,* which includes the halibut
and its relatives, the arctic genera t have from 49 to 50 verte-
bree. The northern genera { have from 43 to 45, the members
of a large semi-tropical genus § of wide range have 35 to q1,
while the tropical forms || have from 35 to 37.

In the group of turbots §[ and whiffs none of the species
really belong to the northern fauna, and the range in numbers
is from 35 to 43. The highest number, 43,** is found ina
deep water species, and the next, 41 and 4o,,f in species
which extend their range well toward the north.

Among the plaices, which are all {{ northern, the numbers
range from 35 to 65, the higher numbers, 52, 58, 65, being
found in species §§ which inhabit considerable depths in the
arctic seas The lowest numbers |||| (35) belong to shore
species which range well to the south.

Concerning this matter, Jordan and Goss remark :

It has already been noticed by Dr. Giinther and others that in certain
groups of fishes northern representatives have the number of their ver-

tebree increased. In no group is this more striking than in the
flounders.

Gill, 1889.—In a review §[4] of the paper above mentioned,
Dr. Gill considers in detail the condition of our knowledge of
this subject, quoting from the various papers mentioned above
and claiming very properly that the first statement of this
generalization belonged to himself rather than to Dr. Giinther.

Dr. Gill further adds:

The case of the sebastines became still more striking when Messrs.
Jordan and Gilbert discovered that the number of vertebrae in the
species of Sebastichthys and Sebastodes, genera intermediate between

the northern Sedasées and the tropical and subtropical representatives of
the family of Scorpenide, was also intermediate.

* Hippoglossine. + Hippoglossus and Atheresthes.

t Hippoglossoides, Lyopsetta, and Lopsetta. 4 Paralichthys.

|| Xystreurys, Ancylopsetta, etc. | Psettine.

** Monolene sessilicauda. tt Lepidorhombus whiffjagonis and
Citharichthys sordidus.

tt Pleuronectine. 2¢ Glyptocephalus and Microstomus.

|||| Platichthys stellatus, Hypsopsetta guttulata.

|] Proceedings of the U. S. National Museum, 1888, p. 604.

Temperature and Vertebre 35

But while claiming the generalization that there is a correlation be-
tween the increase of vertebra and the increase of latitude among
fishes, I would not assign it an undue value or claim for it the dignity
of alaw. It is simply the expression of a fact which has no cause for
its being now known. It may be added that this generalization is true.
ouly in a general sense,

Jordan, 1891.—In another paper* the present writer has,
said :

This increase in the number of vertebre in northern forms has been
used as a basis of classification of the Pleuronectide by Jordan and’
Goss, of the Scorpenide by Jordan and Gilbert, and it will doubtless.
prove to have a high value in the subdivision of other families which
have representatives in different zones. The cause of this peculiarity of!
fishes of cold waters is still obscure. Probably the reduction in num-
ber of segments is a result of the specialization of structure incident to
the sharper competition of the tropical waters, where the outside con-
ditions of life are very favorable for fishes, but the struggle of species
against species is most severe.

In this paper is given a table which shows that in the
genera of Ladrid@ + inhabiting northern Europe and the New
England waters there are 38 to 41 vertebra, in the Mediter-
ranean forms { 30 to 33, in certain subtropical genera § 27 to
29, while in those Ladvozds which chiefly abound about the
coral reefs || the number is from 23 to 25.

Jordan & Eigenmann, 1891.4[/—In a recent paper on the
Serranid@ (sea-bass and groupers) it is stated, that the group
as a whole belongs to the tropical seas, and that it differs from
the related fresh-water family of Percide-by the much smaller
number of vertebree, usually 24, which is the number most
common among spiny-rayed fishes. Among the Serranide,
however, two genera form exceptions to the general rule.
One of these, ** with 35 vertebrae, occurs in the rivers of
China, the other, tf with 36 vertebrz, in the mountain streams

* Review of the Labroid Fishes of America and Europe, p. 2.

¢ Labrus, Acantholabrus, Ctenolabrus, Tautoga.

{ Chiefly belonging to Symphodus. 2 Lachnolaimus, Harpe, etc.

|| Scarus, Spartsoma, Xyrichthys, Julis, Thalassoma, etc.

A Review of the Genera and Species of Serranide found in the
waters, of America and Europe, by David S. Jordan and Carl H. Eigen-
mann.

** Lateolabrax. tt Percichthys.

36 David Starr Jordan

of Chili and Patagonia. In these two genera the numbers
are materially increased, as would be expected if the rule is to
hold good. ‘There are, however, other Sevvanide, more or
less perfectly confined to the fresh waters, and yet retaining
the normal number of vertebree These are perhaps compar-
_atively recent immigrants from the sea. In evidence of this
is the fact that among these forms there is a perfect gradation
in habits from the strictly marine,* through migratoryyt and
brackish-water species{ to those confined to the rivers and
lakes.§

Jordan & Fesler, 1893.\|—In a discussion of the sparoid
fishes by Jordan & Fesler, reference is made to the fact that
the subfamily Aplodactyline inhabiting the south temperate
zone differ from the other Sjavzd@ in the increased numbers
of their vertebree (34 instead of 24) and in the greater numbers
of the rays of the dorsal fin. In most other regards, this sub-
family closely approaches the subfamily Gzvellinge of the
tropics.

Jordan, 1891.—In a paper entitled ‘‘Relations of Tempera-
ture to Vertebrzee among Fishes,’’ (Proc. U. S. Nat. Mus. 1891.
pp. 107-120, I have given a statement of what is known of
this subject, this paper serving as a basis for the present
treatise.

* Dicentrarchus punctatus. + Roccus lineatus.

{| Morone americana. @ Roccus chrysops.

|| A Review of the Sparoid Fishes of America and Europe, by David
Starr Jordan and Bert Fesler, in the Rept. U. S. Fish. Com. published
1893.

PaLo ALTO, CALIFORNIA,
June 15, 1893.

ENGRAVED FOR THE
WILDER QUARTER-CENTURY BOOK,

By ANNA BOTSFORD COMSTOCK.

ALT cf ha

COMSTOCK.

MG i l
ldisluths

ENGRAVED FROM NATURE,

BY ANNA

Li Nal i
SAUL SUNNY

BOTSFORD COMSTOCK.

PLATE

EVOLUTION AND TAXONOMY.

AN ESSAY ON THE APPLICATION OF THE THEORY OF NATURAL SE-
LECTION IN THE CLASSIFICATION OF ANIMALS AND PLANTS, IL-
LUSTRATED BY A STUDY OF THE EVOLUTION OF THE WINGS OF
INSECTS, AND BY A CONTRIBUTION TO THE CLASSIFICATION OF
THE LEPIDOPTERA.

By JOHN HENRY COMSTOCK.

PARSEOIe

A PROPOSED METHOD STATED.

It is now thirty-four years since the publication of Darwin’s
Origin of Species ; and the great war of opinions which had
been imminent for some time, and which broke forth on the
appearance of that work, has been fought to a conclusion.
There remains no contest except that of a healthy competition
in reaping the fruits of the victory. Naturalists differ in their
opinions as to details but the great principle of evolution has
been firmly established, and our methods of thought have
been revolutionized in consequence.

Notwithstanding this I do not believe that the systematists
of to-day are making as much use of the theory of descent in
taxonomic work as they might. We are still busy describing
species as if they were immutable entities ; and in our descrip-
tions we give little thought to the causes that have determined
the forms of organisms. It is true that considerable has been
done in the direction of working out the phylogeny of the
larger groups, as branches and classes, and to a less extent of
orders. But rarely is any effort made to determine the phy-
logeny of the smaller groups.

Here I believe lies the work of the systematist of the future.
The description of a species, genus, family or order, will be
considered incomplete until its phylogeny has been determined
so far as is possible with the data at hand. Weare to care less
for the mere discovery of new forms, and more for an under-

38 John Henry Comstock

standing of the processes by which new forms have arisen.
The object of taxonomy will not be a mere grouping of forms
according to similarity of structure. But the systematist will
have constantly before him the question : What do these vari-
ations of form mean? With this change in the object of tax-
onomic work, there will come a change in its methods. It is
strange that the change has been so long delayed ; for we are
really using the same methods that were employed before the
establishment of the truth of the theory of natural selection.
What these methods are was indicated by Darwin in the fol-
lowing words :

‘* Practically, when naturalists are at work, they do not
trouble themselves about the physiological value of the char-
acters which they use in defining a group or in allocating any
particular species. If they find a character nearly uniform,
and common to a great number of forms, and not common
to others, they use it as one of high value; if common to
some lesser number, they use it as of subordinate value.’’
(Darwin, Origin of Species, pp. 367-368, Am. Edition. )

This statement is about as true to-day as when Darwin
wrote it. For if one will look through the taxonomic works
on zoology or botany he will very seldom find any reference
to the functions of organs. But almost all naturalists now
believe that in each epoch of time the forms of existing or-
ganisms have been determined by a survival in preceding
generations of those individuals whose parts were best fitted
to perform their functions.

Does it not follow from this belief that we can confidently
expect to gain much help in our efforts to work out the phy-
logeny of organisms by making a careful study of the func-
tions of their organs, and endeavoring to understand the rea-
sons for the action of natural selection ?

I suggest, therefore, that the logical way to go to work to
determine the affinities of the members of a group of organ-
isms is first to endeavor to ascertain the structure of the primi-
tive members of this group ; and then endeavor to learn in what
ways these primitive forms have been modified by natural
selection, keeping in mind that in each generation those

Evolution and Taxonomy 39

forms have survived whose parts were best fitted to perform
their functions.

Obviously there are certain difficulties in the carrying out
of this plan. But the measure of our success in determining
the affinities of the organisms studied, will depend largely on
our ability to overcome these difficulties.

Among the difficulties encountered is the fact that usually
our classification must be based largely on a study of living
forms; for in most cases the aid to be derived from Palaeon-
tology is comparatively slight. But although the record pre-
sented by fossils is very fragmentary, fortunately there are
many living forms which are comparatively slightly special-
ized. And these will serve to give an idea of the stem form
of the group.

Thus to carry out the plan suggested, the zoologist or
botanist, if he is forced to work only with living animals or
plants, will select from the group to be studied the most gen-
eralized type before him, and then trace out the different ways
in which this type has been modified in the more specialized
forms.

If the group studied be a large one, the probabilities are
that instead of a single primitive type, several generalized
forms will be found, each representing more or less approxi-
mately the stem form of a distinct line of development ; and a
comparative study of these different forms will be necessary
in order to obtain an idea of the structure of their common
ancestor.

But how shall one go to work to select from a large number
of forms those that are to be considered the more generalized ?
The higher animals and plants are such complex organisms
that it is not an easy matter to determine the relative degree
of specialization of two distinct forms. The problem is also
complicated by the fact that even the more generalized forms
may present specializations peculiar to themselves.

Numerous examples will occur to any systematist of forms
which as a whole are comparatively generalized, but which in
some respects are highly specialized, being, as has been ex-
pressed by some writers, ‘‘ sidewise developed.’’ It is essen-

40 John Henry Comstock

tial that these sidewise developments be not included in our
conception of the still more primitive form.

Thus the Thysanura are regarded as the most generalized
of the living Hexapoda. ‘This would also be the case if of
this order only the suborder Collembola were known to us.
In such a case we might conclude from a study of the spring-
tails that the primitive Hexapoda possessed a ventral sucker
and a caudal spring, and that these organs had been super-
ceded by the wings in more specialized forms. Now we
know that while taken as a whole the Collembola are very
generalized insects, that so far as the ventral sucker and
caudal spring are concerned they do not represent the primi-
tive type of the order, but are sidewise developed. In both
the Cinura and the Collembola we find forms which are
clothed with highly specialized scales, scales which rival in
complexity of structure those of the Lepidoptera. Yet no
one believes that the primitive Hexapoda were so clothed.
This is another sidewise development. And the scales of the
Lepidoptera, and of the Curculionide, for example, have
arisen independently.

We thus see that although in our efforts to trace out the
series of modifications through which a line of organisms has
passed we may find forms which appear primitive, we must
not expect to find among living forms an exact record of these
changes. Each form studied will represent the tip of a twig
which has separated from the main branch. Fortunately for
our purpose we can often find some forms representing twigs
that branched off very early and that have not grown very far
in their special direction. In many cases too, forms are found
which although highly specialized as regards some of their
organs will retain a generalized condition of otherorgans. By
a comparison of a number of such forms each representing a
generalized condition of some of its organs we can get an ap-
proximate idea of the common progenitor.

But I repeat, how shall we determine which are the repre-
sentatives of those short twigs that have undergone but little
change, and which are the representatives of branches that
have been greatly modified ? The answer to this question is

Evolution and Taxonomy 41

a statement of the method I propose for applying the theory
of natural selection to taxonomy more fully than has been
done before.

As the structure of a highly organized animal or plant is too
complicated to be understood in detail at once, it is suggested
that the student begin with the study of a single organ
possessed by the members of the group to be classified, and
that his studies take the following course: First the variations
in form of this organ should be observed, including palzeonto-
logical evidence if possible; then its function or functions
should be determined. With this knowledge endeavor to de-
termine what was the primitive form of the organ and the
various ways in which this primitive form has been modified,
keeping in mind the relation of the changes in form of the
organ to its function. In other words endeavor to read the
action of natural selection upon the group of organisms as it
is recorded in a single organ, The data thus obtained will
aid in making a provisional classification of the group.

When this stage has been reached another organ should be
selected and its history worked out in a similar way.

The results of the two investigations should then be com-
pared ; and where they differ there is indicated the need of re-
newed study. For if rightly understood the different records
of the action of natural selection will not contradict each
other. The investigation should be continued by the study
of other organs and a correlating of the results obtained until
a consistent history of the group has been worked out.

This method differs from that commonly employed in being
a constant effort to determine the action of natural selection
in the modification of the form of organisms in order to better
adapt their parts to preform their function. Ordinarily little
or no attention is devoted to the study of the functions of
organs in purely taxonomic works.

If the history of a group be worked out in the manner indi-
cated, the student will feel the need of recording his results in
such a way as to indicate the phylogeny of the divisions of the
group. But as the necessities of book making require a linear
arrangement of descriptions this is somewhat difficult ; for the

42 John Henry Comstock

natural sequence of groups should be represented by con-
stantly branching lines rather than by a single straight line.

It seems to me that the most practicable way of meeting this
difficulty is to begin with the description of the most general-
ized form known, and to follow this with descriptions of forms
representing a single line of development, passing successively
to more and more specialized forms included in this line.
When the treatment of one line of development has been com-
pleted take up another line beginning with the most general-
ized member of that line and clearly indicating in the text that
a new start has been made.

Much aid can also be given by a tabular statement of the
essential characters of the subordinate groups, using the form
of the ordinary analytical table. An illustration of this is
given in Part III of this essay.

In this connection reference should be made to the proper
position of degraded forms in a series where an effort is made
to represent the natural sequence. The common practice of
assigning such forms the same position that would be assigned
to them if their simplicity of structure was the result of a,
primitive condition seems to me illogical. An example will
make this point clear. The Hemiptera are doubtless all de-
scended from acommon winged ancestor. The lice, although
more simple in structure than most other members of the
order, do not represent the form of this ancestor as closely as
do the winged members of this order. ‘Chey should not,
therefore, be placed first in the hemipterous series as is com-
monly done. It would represent the facts of nature better to
place them last, as forms departing more widely from the
primitive type of the order than do the winged forms. But it
should be clearly indicated that although they represent the
tip of one of the lines of development that line is a downward
bending line.

In attempting to work out the phylogeny of a group of
organisms, there will arise, I believe, the necessity of distin-
guishing between two kinds of characters: first, characters
indicating differences in kizd of specialization ; and second,
characters indicating differences in degree of specialization of

Evolution and Taxonomy 43

the same kind. ¢Yhe former will indicate dichotomous divis-
ions of lines of descent ; the latter will merely indicate de-
grees of divergence from a primitive type. Thus, to draw an
illustration from the following pages, it is shown that there
are two distinct ways of uniting the two wings of each side
in the Lepidoptera; they may be united by a frenulum (Fig.
22) or the may be united by a jugum (Fig. 27). These are
differences in kzézd of specialization, and indicate two distinct
lines of descent or a dichotomous division of the order.
Among those Lepidoptera in which the wings are united by
a frenulum great differences occur in the degree to which this
organ or a substitute for it is developed ; such differences may
merely indicate the degree of divergence from a primitive type
and may need to be correlated with other characters to indi-
cate dichotomous divisions.

It is impracticable to indicate degrees of divergence from
the primitive type based on the nature of the frenulum at this
stage of the discussion ; but another character will serve our
purpose well. Inthe more generalized Lepidoptera the anal
areas of one or of both pairs of wings are furnished with three
anal veins; while in more specialized forms the number may
be reduced to two or even to one. But the distinctions indi-
cated by the presence of three, two, and one anal veins in dif-
ferent moths, are merely differences in degree of specialization
by reduction of an anal area, and taken alone will not indicate
dichotomous divisions. Thus if we group together all the
moths that have retained three anal veins in the hind wings,
such a group will contain, not merely the Microlepidoptera,
as iscommonly stated, but also the more generalized members
of several distinct divisions of the Macrolepidoptera.

The fact is, the primitive Lepidoptera evidently possessed at
least three anal veins in the hind wings (we will omit the fore
wings from the discussion for the time being). In several dis-
tinct lines of development within this order the direction of
specialization of the anal area of the hind wings has been
towards the reduction of the number of veins in this area; but
the extent to which this reduction has gone merely indicates
the degree of divergence from the primitive type. And so far

44 John Hlenry Comstock

as this single character is concerned a similar degree of diver-
gence in a similar direction may be possessed by members of
widely separated divisions of the order.

But we are not entirely dependent on differences in kind of
specialization for indications of dichotomous divisions. Such
divisions may be indicated by differences in the order in which
specializations take place.

This also can be illustrated by a study of the anal areas of
the wings. It is evident that in the primitive Lepidoptera the
fore wings as wellas the hind wings possessed three anal veins.
And in certain divisions of the order the direction of special-
ization of the anal area of the fore wings has also been to-
wards a reduction in the number of veins. It will be shown
in the concluding part of this essay that in certain divisions of
the order the reduction of the anal area of the hind wings has
preceded the reduction of the anal area of the fore wings;
while in other divisions of the order the reverse is the case.
Here is an indication of a dichotomus division. Take for
example two families of moths, one of which is characterized
by the presence of two anal veins in the fore wings and three
anal veins in the hind wings; and the other, by three anal
veins in the fore wings, and two in the hind wings. In the
former, the specialization by reduction of the anal areas has be-
gun in the fore wings; in the latter, this specialization has be-
gun inthe hind wings. And it is evident that the common
progenitor of the two families had three anal veins in both fore
and hind wings, and that the difference in the order in which
the reduction of the anal areas has begun indicates a dichoto-
mous division.

There will also arise, I believe, in a work of this kind a ne-
cessity for distinguishing between the essential characters of
a group and those characters which are used by the systema-
tist merely to enable students to recognize members of the
group. For it seems to me that the essential characters of a
group of organisms do not lie necessarily in the presence or
absence of any structure or structures, or in the form of any
part or parts of the body of the living members of the group ;
but rather in the characteristic structure of the progenitor of

Evolution and Taxonomy A5

the group, and in the direction of specialization of the de-
scendants of this progenitor.

Thus, to use again the illustration given above, the Jugatee
are essentially characterized as the descendants of those an-
cient Lepidoptera in which the wings of each side were united
by a jugum ; and they are also characterized by a tendency
towards an equal reduction of the veins of the two pairs of wings.
While the Frenatee are essentially characterized as the descend-
ants of those ancient Lepidoptera in which the wings ofeach side
were united by a frenulum ; and they are also characterized by
a tendency towards a greater reduction of the veins of the hind
wings than of the fore wings, or, in other words, by a tendency
towards a cephalization of the powers of flight. The fact that
in many of the Frenatze the frenulum has been lost, does not
invalidate in the least the truth of this characterization. The
loss of the frenulum, however, in certain Frenatze renders
necessary the use of some other character or characters by the
systematists as recognition characters.

The recognition characters are those usually first observed
by the investigator, and are those commonly given in taxo-
nomic works. In many cases these recognition characters are
also essential characters, especially in the case of groups that
have been thoroughly studied. But by the taxonomic
methods now commonly used search is chiefly made for recog-
nition characters. The more skilled the systematist the more
likely is he to discover and use as recognition characters
those that are really essential, although the distinction pointed
out here may not be recognized by him.

In the case of those groups where but few or no general-
ized forms have persisted till this time, the essential characters
must to a greater or less extent be inferred. This is espec-
lally true of those characters which refer to the structure of
the progenitor of the group. But the direction of specializa-
tion may be shown by a single representative of the group, if
it be highly specialized, and we have a clear idea of the essen-
tial characters of a larger group including the one under inves-
tigation.

It must be borne in mind, however, that the direction of

46 John Henry Constock

specialization may undergo marked changes in the course of
the history of a single line of development. Thus I feel sure
that in the ancient Frenate the tendency of specialization
was towards more rapid flight which tendency resulted in the
preservation of the narrower winged forms. But while this
tendency has been continued in certain divisions of the group
to the present time, so that in these divisions the most highly
specialized forms have the narrowest wings (Sphingide,
Zygeenina), there are other divisions in which the tendency
has been changed towards a different mode of flight, and has
resulted in the preservation of the wider winged forms, and in
these divisions the most highly specialized forms are those
having the widest wings. (Saturniina.)

In recording the results of specialization one is apt to speak
as if there were an intelligent directing force which determines
the direction of specialization ; or as if individuals deliber-
ately chose the way in which they should vary from their pro-
genitors. The fact that we are often able to arrange the mem-
bers of a group in well defined series, each series culminating
in a specialized form towards which the other forms approxi-
mate in varying degrees of closeness, leads to the unconscious
use of such expressions. It is difficult to keep constantly in
mind the extent of the thinning out process that takes place
in nature, that the objects of our studies are merely a few for-
tunate individuals that have withstood tests that have proved
fatal to the great majority. Innumerable unfortunate varia-
tions perish and leave no record; we see the fortunate ones
alone ; and the impression is apt to be that there is a definite
progression on the part of all. Perhaps the facts of the case
can be expressed as follows: The conditions which surround
an organism combined with the existing structure of that
organism render variations in its offspring in certain definite
directions fortunate, while variations in other directions are
unfortunate. As the fortunate variations alone are preserved
to us the record seems to indicate a strong tendency to vary in
definite directions.

In this paper the terms generalized and specialized are used
in preference to low and high, which are often loosely used as

Evolution and Taxonomy 47

synonyms of these terms. It should be remembered that low-
ness or simplicity of structure may be the result of degrada-
tion, and hence does not necessarily indicate a primitive or
generalized condition. The lice are the lowest of the Hemi-
ptera ; but they are by no means the most generalized of the
living members of that order.

Professor Hyatt has pointed out* that specialization may
take place in two different ways: first, by an addition or com-
plication of parts, specialization by addition ; second, by a re-
duction in the number or in the complexity of parts, speczal-
ization by reduction. ‘These expressions are very convenient
in indicating the direction of specialization of an organ or set
of organs.

Another important principle, first pointed out, I believe by
Meyrick is that ‘‘ When an organ has wholly disappeared in
a genus, other genera which originate as offshoots from this
genus cannot regain the organ, although they might develop
a substitute for it.’’

The truth of Meyrick’s law, as this last principle may be
termed is obvious when we consider that if a part be wholly
lost there is nothing for natural selection to act upon in order
to reproduce it. And even if a necessity for the organ should
again arise and a substitute be developed for it, it is not at all
probable that the substitute would resemble the organ so
closely as to be mistaken for it.

In the application of Meyrick’s law care must be taken that
comparison be made only between allied forms, z. ¢., within
what may be termed a single line of descent. I recognize the
fact that these expressions are indefinite, but I believe no
systematist will have doubt as to my meaning.

Let me state the matter in another way. ‘The loss of an
organ is a character that merely indicates a degree of diver-
gence from a primitive type. And so far as any single organ
is concerned this stage may be reached in one line of descent
very much earlier than in another. In fact the loss of an
organ may be correlated in one line of descent with a very

* Insecta, page 51.
¢ Trans. Lond. Ent. Soc. 1884, page 277.

48 John Hlenry Comstock

generalized condition of other characters; while in another
line of descent very highly specialized forms may still possess
the organ in question.

A good illustration of this is presented by the condition of
the mouth in the Macrolepidoptera. In many moths the
mouth parts are wanting, while in other moths and in butter-
flies the maxillae are very highly specialized. It cannot be
concluded from this fact that the mouthless forms are farther
removed from the primitive type than are the sphinges and
butterflies for example. A study of other structures would
not support such a conclusion. We have to do ina case of
this kind either with very distinct lines of descent or with a
sidewise development.

In the case of the organ selected, the mouth, there comes
into play, I believe, a very peculiar principle. For a long
time I was greatly puzzled by the many instances in which
absence of mouth parts is correlated with a very generalized
condition of other structures. The explanation of this phe-
nomenon I now believe to be as follows : Under certain condi-
tions natural selection may tend to change the length of the
adult stage. Insome cases those individuals that most quickly
provide for the perpetuation of the species are the ones that are
most likely to have offspring. Under such conditions there
would be a shortening of the duration of the adult stage until a
point was reached at which it would not be necessary for the in-
sect to take food during the adult stage, and the mouth parts
would be lost in this stage.

But this shortening of the duration of the adult stage would
also tend to a great degree to remove the species that had ac-
quired it from the struggle for existence in this stage. A
species that found it necessary to fly only a few hours or even
days in order to provide for the perpetuation of its kind would
not offer such an opportunity for the action of natural selec-
tion upon the structure of its wings and other organs peculiar
to the adult, as would surely occur in a species having a
longer period of flight.

Evolution and Taxonomy 49
BART ie
THE EVOLUTION OF THE WINGS OF INSECTS.

This essay is an outgrowth of an effort to determine the
_ phylogeny of the families of the Lepidoptera, in order to de-
cide upon a classification to be used in a general text book of
Entomology. More than three years were devoted to the prob-
lem before a systematic method of procedure was adopted.
This time was largely spent in a comparative study of pub-
lished classifications and in an effort to determine which of
these represented most accurately the facts of nature. A large
part of the work yielded poor returns for the labor expended ;
for it was carried on with no definite plan; it was a blind
groping in the dark.

Suddenly one day a flood of light was thrown upon the
work by the recognition of the fact that a moth which I was
studying (Aepialis, Plate I, Fig. 2) was a generalized type.
I found that a knowledge of the structure of this insect gave
a clue to the probable structure of the primitive Lepidoptera.
And that with this knowledge it was not too much to expect
to be able to trace out the various lines of descent represented
by existing forms. Then began a systematic study which
has resulted in the development of the method outlined in
Part I of this essay.

I regret that I have been unable to apply the method as
fully as I should like to before publishing it. But the results
which I have been able to obtain by it lead me to hope that
the publication is not premature. And as the leisure which
a teacher can get for study is limited, I could not hope to
make a complete application of it, even to the families of a
single order, for many years.

A complete application of the method to the Lepidoptera
alone will involve a study of the segments of the body a sa
whole, the peculiarities of development of particular segments,
the structure of internal organs, the structure of organs of
special sense, the various appendages of the body as antennae,
mouth-parts, legs, wings, and the external appendages of the
reproductive organs, the clothing of the body, in a word the

50 John Henry Comstock

study of every structure that has been developed in these in-
sects.

But although this extended study will be necessary before
we can consider our work complete, a provisional classification
can be based on the study of a single organ or set of organs.
We have only to remember that such a classification is merely
provisional, and that the results obtained in this way should
be confirmed or corrected by the study of other organs.

Following the method indicated, the wings were selected as
the first organs to be studied. ‘These organs were chosen as
the most available ones, owing to their size, and the ease with
which variations in their structure could be observed. The
record of the action of natural selection is recorded upon
them as upon a broad page. For a long time my attention
was confined to the wings of the Lepidoptera. But later I
found it necessary to greatly extend my studies in order to
determine the primitive type of the wings of insects. It was
also necessary to study the wings of insects of other groups in
order to select a nomenclature of the wing veins that would
apply to all orders of insects.

Although there are great differences in the venation of the
wings of insects of different orders, a study of the more gen-
eralized members of the several orders of winged insects show
that the type of venation is the same for them all. This indi-
cates two points of great scientific interest : first, wings have
originated but once in the class Hexapoda, or, to state the
same thing in other words, all of the orders of winged insects
have descended from a common stock; second, if all the
various forms of wings are modifications of the same type, it is
not too much to expect to be able to establish a uniform no-
menclature for the principal elements in the frame work of
the wings, z. é., the principal veins, although doubtless it
will be necessary to use special names in many cases for
structures that have been developed secondarily.

The importance of the wings of insects for taxonomic pur-
poses was early recognized by entomologists, as is well shown
by the fact that the names of the Linnean orders are all
drawn from the nature of the wings, except one, Affera, and
that from the absence of wings.

Evolution and Taxonomy 51

Although, doubtless, the great extent to which the wings
are still used in taxonomy is partially due to the ease with
which wing characters can be observed, still the following
considerations show that such use is warranted by the facts of
nature.

The chief end of existence of an adult insect is to provide
for the perpetuation of the species. This resolves itself in the
case of the male into seeking a mate; and in the case of the
female after accepting a mate, into seeking a proper nidus for
her eggs. In the case of certain insects special conditions ne-
cessitate a prolonged existence in the adult state in order to
accomplish this end in the best manner ; in such cases there
may exist a necessity for seeking food; but in many families
all nourishment is taken during the adolescent stages.

The necessity for seeking mates or for properly placing
eggs, as well as for seeking food gives great importance to
organs which increase the power of locomotion. It follows
from this that when organs of flight had once been, developed
such organs would furnish an important field for; the action
of natural selection.

It has been indicated that there is good reason to believe
that all winged insects have descended from a, common
winged ancestor. But we find that the primitive type of
wing has been modified in many widely. different ways.
Hence a study of the various ways in which, wings have been
specialized can not fail to throw much light on the phylogeny
of insects.

The fact that in some cases, notably those of most animal
parasites, wings, becoming unnecessary and perhaps even
detrimental, have been lost does not lessen the value of. these
organs for taxonomic purposes when they have been. pre-
served.

It is often urged, that as the wings are merely appendages
of the body, they are extremely liable to be modified in form ;
and that consequently we cannot hope to find in them a very
permanent record. In other words, while it is generally ad-
mitted that variations in the framework of the wings may give
us important clews as to the limits of the genera, we can not

52 John Henry Comstock

hope to base conclusions upon them as to the limits of larger
groups. But it does not follow, that because an organ is asu-
perficial one, it is of little value in suggesting broad general-
izations. We find that often the most superficial of structures
are among those that were developed very early in the history
of a large group, and have persisted almost unchanged in
form, although more central structures have been greatly and
variously modified. Thus the form of mere dermal appen-
dages may present characters of very high value, as the hair
of mammals and the feathers of birds ; even the Cefacea have
hair, and Archopteryx had feathers. As ‘the proof of a
pudding is in the eating,’’ so the value of a character for tax-
onomic purposes can be determined only by its use.

As to the origin of wings we have noknowledge We have
not even a generally accepted theory to account for the appear-
ance of these structures. Many writers believe that they are
modified tracheal gills. We find in many aquatic nymphs
plate-like gills, some of which would need to be modified but
little to function as organs of locomotion. This is especially
true of the covering pieces forming part of the respiratory ap-
pendages of an Ephemerid nymph. ‘These pieces not only
protect the gills beneath them ; but probably
also serve by their flapping to cause a cur-
rent of water to pass over the gills. Fig. 1
represents the covering piece of a tracheal
gill of an Ephemerid nymph collected at
Fic. 1.-Covering- Ithaca. ‘The step from such a structure to

cil of ees sat one that would aid in locomotion is not a
great one.

But other writers think that the wings arose as keel-like
expansions of the sides of the thorax. Such expansions
would function as a parachute in a falling insect, as does the
folds of skin in a flying squirrel, or would function both as a
kite and a parachute in a leaping insect.

In support of the latter theory the netted-veined triangular
prolongations at the sides of the prothorax of certain fossil
insects (Choredodis and Lithomantis, Fig. 2) are brought for-
ward ; and itis also said that a species of Tingis from Texas

Evolution and Taxonomy 53

shows on the prothorax, transparent projections of triangular
form and a netted venation similar to that of the fore wings*.

Whatever the origin of wings may have been, I think that
this much is clear: they were developed to comparatively
large size and were furnished with numerous veins before they
began to function as active organs of flight. This large size
and rich venation may have been the result of a natural selec-
tion of those forms best fitted to act as a kite or a parachute.
But this type of wing is not well adapted for active flight.
-As soon as there arose a tendency for the wing to function in
this way, there began, doubtless, the extensive series of mod-
ifications of which we have records both in the rocks and
among living insects.

We know almost as little regarding the origin of the veins
of the wings as we do of the wings themselves. Still we may
be allowed to speculate regarding the matter. Let us suppose
that the wings originated from
broadly expanded organs; such
organs would be furnished with
tracheze, even if they were used
only as a parachute; for they
would need to be supplied with
air as are other parts of the body.
On the modification of such or-
gans into wings fitted for active
flight, it would be important that IG
the main trunks of the tracheze
should be protected in such a way that any bending of the
wing, which would compress them and thus choke off the
supply of air, would be avoided. Thus any tendency of the
membrane of the wing to become thickened along the lines of
the tracheze would be preserved by natural selection ; and cor-
related with the development of this firm frame-work, there
might be a thinning of the spaces between the main trachee,
oes insuring lightness of the entire organ.

* Josef Rettenbacher, Vergleichende Studien tiber das Mineeleeider
der Insecten Ann. des k. k. naturhistorischen Hofmuseums, Wien, Bd.
I. 153-232, t. IX-XX.

54 John Henry Comstock

We are not entirely without evidence that this is the method
of the formation of wing veins. It will be shown later that
when the principal stem of one system
of veins (media) is obliterated and the
branches of this system are forced to
derive their supply of air through lat-
eral tracheze extending to adjacent
systems of veins, these lateral tracheze
become enveloped by veins resembling
in every respect the principal veins.

Fic. 3.—Falegoblattina eh :
douvillei. Similar evidence may be drawn from

the study of the development of the
humeral veins in the Lasiocampide.
Since we are not able to determine the form and function of

the organs which were modified into wings, let us endeavor to
select the most generalized type of wings preserved to us. We
will first see what light Paleeontology throws upon this ques-
tion

Comparatively little is known regarding the primitive in-
sects. But thanks to the labors of Mr. S. H. Scudder, who
has been one of the chief workers in this field, what is known
has been made easily accessible.*

Winged insects appeared very early, probably as early as
any land plants ; for Moberg has figured
an insect (in the Forhandlingar of the
Swedish geological society) from the
upper part of the lower silurian; and
Brongniart has figured and described a Bic, A Homothetus
wing from the middle silurian sandstone fossilis.
of Calvados, France. (Fig. 3). But this
wing instead of being primitive in form represents a rather
highly specialized type, if the figure given correctly represents

* Zittle. Traite de Paleontologie t. II.
Bull. U. S. Geol. Survey No. 31.
Bull. U. S. Geol. Survey No. 69.
Fossil Insects of North America. Vol. I. Pretertiary Insects.
Index to the known Fossil Insects of the World, including Myria-
pods and Arachnids. Bull. U. S. Geol. Survey No. 7:.

Evolution and Taxonomy 55

its structure. And the insect described by Moberg (Profoci-
mex siluricus) is supposed by him to be hemipterous, an even
more highly specialized type.

Of devonian insects we know several. Those which are
best preserved are Homothetus fossilis (Fig. 4), Xenoneura antt-
quorum (Fig. 5), and Platephemera
antiqua (Fig. 6). These differ
among themselves to such an ex-
tent that we are forced to conclude
without taking into account the
two known silurian insects, that
already at that early time there
was a large and varied insect fauna, of which the more
primitive forms have not been discovered.

From the carboniferous rocks much more abundant material
has been obtained. But, according to the views of Mr. Scudder
‘there existed among these ancient forms no ordinal distinc-
tions, such as obtain to-day, but they formed a single homo-
geneous group of generalized hexapods, which should be
separated from later types more by the lack of those special
characteristics which are the property of existing orders than
by any definite peculiarity of its own.’’ *

FIG. 5.—Xenoneura anti-
quorum.

To this group of generalized
hexapods which includes all pa-
leozoic insects the name Palgo-
dictyoptera has been applied.

Among the Palaodictyoptera
were insects which were un-

Mie “6 Piatephemera doubtedly the precursors of the

antigua. cockroaches, the may-flies, and

the walking-sticks. Still these

groups of insects ‘‘ were more closely related to one another,
at least in the structure of their wings (which is the only
point of general structure yet open for comparison) than any
one of them is to that modern group to which it is most
allied.’’ The ordinal distinctions which is now found in
the ‘‘wing structure of modern insects did not exist in

*Bull. U. S. Geol. Survey. No. 31 p. 104.

56 John Henry Comstock

paleozoic insects, but a common simple type of venation
which barely admitted of family divisions.’’ *

In his classification of the Palzeodictyoptera,t Mr. Scudder
indicates a number of these family divisions, and groups them
according to their general facies and by their relationship to
succeeding types into four sections as shown by the following

table. t
PALASODICTYOPTERA.
ORTHOPTEROIDEA.

1. Fam. Palgoblattarie.
Subf. MWylacride.
Subf. Blattinarie.
2. Fam. Protophasmide.
NEUROPTEROIDEA.
1. Fam. Palephemeride.
. Fam. Homothetide.
Fam. Falgopterina.
Fam. Xenoneuride.
Fam. Hemeristina.
Fam. Gerarina.
HEMIPTEROIDEA.
Eugereon, Fulgorina, Phthanocoris.
COLEOPTEROIDEA.
Borings supposed to be of beetle-like insects.

ANON

It is evident from a study of the fossil remains that our
knowledge of the primitive Palzeodictyoptera is very frag-
mentary. ‘The few forms that have been discovered in the
silurian and devonian rocks are evidently more highly special-
ized than certain other forms which have been found in the
carboniferous ; the most generalized wings known to us, as I
shall show later, being from this epoch. We must, therefore,
turn to the carboniferous as the earliest epoch from which we
have data to base our conclusions regarding the structure of
the primitive insect wings.

As this is a comparatively late period we are forced to pur-
sue practically the same method that we would were we to at-
tempt to solve the problem by a study of living insects. That

*Scudder. Pretertiary Insects p. 319, 320.

+ Zittle Traite de Paleontologie t. II. and in Bull. U. S. Geol. Survey
No. 31.

{It would be presumptuous for one who has studied the paleozoic in-
sects so little as I have done to criticise the accepted classification of
them. Itherefore quote it without change, although it does seem to
me that ordinal distinctions arose earlier than indicated by Mr. Scudder.

Evolution and Taxonomy io

is we must select what seems to be the more generalized types
and try toeliminate from these the results of sidewise develop-
ments.

What is gained by the study of carboniferous insects, I be-
lieve, is the demonstration that certain characters which have
been commonly considered primitive did not exist with these
insects, and consequently must be considered as secondary
developments.

A comparative study of these insects show that in the Palze-
odictyoptera the two pairs of wings were very similar in
structure both being membranous and furnished with a simi-
lar framework of veins.* Each wing possessed six principal
veins or groups of veins which are clearly homologous
with the costa, subcosta, radius, media, cubitus, and anal
veins of modern insects. The wings when not in use were
closed over the abdomen. ‘They were sometimes broadly
folded but were never plated, as arethe hind wings of the Acri-
didze forexample. This feature being with little doubt a com-
paratively late development. (See Scudder, Pretertiary In-
sects, p. 49.)

It seems to me probable that the Palephemeridz presented
an exception to the general statement given above, in that the
two pairs of wings were not of equal size. The shape of the
fore wings of Platephemera antiqua (Fig. 6) is such as to in-
dicate that the hind wings were small. And I am informed
by Mr. Scudder that the only paleozoic may-fly known that
shows the hind wings at all (Palingenia feistmantelz) shows
that they must have been broad and in all probality much
shorter than the fore wings. f

* We find here an intermembral homology analogous to that which
exists between the fore and hind limbs of Vertebrates. See an exhaus-
tive paper by Wilder on Zztermembral Homologies, Proc. Bost. Soc. of
Nat. Hist. vol. XIV, p. 154.

{In fact I do not believe that the living May-flies are so primitive as
regards their wing structure as has been commonly supposed. They
have attained a high degree of cephalization of the function of flight,
as shown by the reduction in size of the hind wings, and the large de-
velopment of the mesothorax. The subcosta and radius are nearly
parallel with the costa and closely approximated to it; the wings are
well corrugated ; and au extensive system of concave veins have been
developed. Each of these characteristics is discussed later.

58 John Henry Comstock

Although the wings of the Paleeodictyoptera agree in the
characteristics given above they present great differences of
structure. How shall we decide which of the different forms
is the more primitive. This I think can be done by determin-
ing the degree of their adaptation to the performance of their
function.

In those insects which have the best developed powers of
flight we find that the costal edge of the front wings is the
strongest part of the wing, the strength being due to the
presence of several strong veins which are nearly parallel.
Such an arrangement is necessary to withstand the strain that
is brought upon this part of the wing. I conclude, therefore,
that wings possessing this structure are more highly special-
ized than those in which the costal edge is not strengthened
in this way. Using this criterion I select that form of wing
which departs most widely from this type as the most gener-
alized form ; for so important a character as this when once
attained would not be lost so long as the wings were used as
organs of vigorous flight. I conclude, therefore, that it is
among the carboniferous coachroaches that we find the most
generalized form of wing.

Owing to our limited knowledge of extinct forms, I cannot
hope to present in these studies continuous series ; but can only
select examples which illustrate the direction or directions of
specialization of particular parts, without strictly confining
myself to a single line of development.

In Mylacris anthracophilum (Fig. 7) the wing is furnished
with five sets of veins in addition to the costal or marginal
vein if this exists. Three of these which oc-
cupy the intermediate area of the wing arise
each in a single strong trunk. ‘These veins
may be designated beginning with the one

nearest the costal margin as the radius, media,
ued Oe and cudbitus, respectively.
philum. Lying between the costal edge of the wing
and the radius there is a group of veins which
radiate from near the base of the wing (Fig. 7, II). ‘These I
believe represent the swdcosta in its most generalized form.

Evolution and Taxonomy 59

These subcostal veins resemble very closely in form and ar-
rangement the group of veins lying behind the cubitus, the
anal veins. In fact a longitudinal line drawn through the
center of the wing divides it into two nearly similar halves.

It will be readily seen that this
type of wing is poorly fitted for active
flight ; the costal edge lacking the
strength necessary for this purpose.
In fact the arrangement of the veins
approximates that of the covering Fic. 8.—Necymylacris
piece of a tracheal gill figured above heros.

(Fig. 1), or that of the lateral ap-
pendages of the prothorax of Lithomantis (Fig. 2).

In Necymylacris heros (Fig. 8, II) we see the beginning of
a strengthening of the subcostal area. One of the subcostal
veins, the hindermost, becomes the principal vein of this area;
and most of the other subcostal veins have become consoli-
dated with this one, so as to appear to be branches of it. The
subcostal area is also relatively much narrower.

In L£ctoblattina lesquereuxtt (Fig.
g) the tendency of the many sub-
costal veins to become consolidated
into a single strong vein with branch-
es extending to the costa is carried

EZZZ

Fic. 9.—Ectoblattina much farther; and the narrowing
lesquereuxit. of the subcostal area is also more
marked.

The step from the form of the subcosta in £cfoblattina to
that presented by many modern insects is not a great one, as
for example, that of the fore wing of Corydalts.

It is probable that correlated with the lengthening and nar-
rowing of the subcostal area in these paleozoic insects a
thickening of the costal edge of the wing took place, thus
forming the costal vein. As I have been able to study only
figures of these paleozoic remains, I am unable to decide at
what point in the development of the wing a distinct costal
vein was formed. It was probably very early ; for Mr. Scudder
states that in the paleozoic insects the six principal veins

60 John Henry Comstock

were always developed, the marginal [costa] simple and
forming the costal border.

From this brief study of the development of the subcostal
area let us pass to the area lying next to the opposite margin
of wing, the anal area, omitting for a time any discussion of
the three veins (radius, media and cubitus) which occupy the
central portion of the wing.

A striking feature in the structure of the wings of many in-
sects is the separation of the anal area from the remainder of
the wing by a fold or furrow, along the bottom of which ex-
tends a vein. Such a depressed vein has been termed, on ac-
count of its position, a concave vein; and in contradistinction
to such veins, those veins which extend along the summit of
ridges, or which are more prominent on the upper surface of
the wing than on the lower, are termed convex veins.

This furrow separating the anal area from the preanal por-
tion of the wing appeared very early. It is especially promi-
nent in all cockroaches both fossil and living ; and can usu-
ally be recognized in any insect wing in which the anal area
is well developed. I have been unable to determine the sig-
nificance of it. But have found it a very useful mark in de-
fining the limits of the anal area. It is vein VIII of the
nomemclature adopted in this paper.

The primitive form of the anal area is probably well shown
in Mylacris, (Fig. 7), where it closely resembles the primitive
form of the subcostal area, as shown in the same genus. But
the latter specialization of this area has been very different
from that of the subcostal. This specialization has taken
place in two opposite directions, z e., by reduction and by
addition.

In certain lines of development the tendency of natural
selection has been to preserve the narrower winged forms.
And the narrowing of the wings has taken place largely
through a partial or complete reduction of the anal area.
The dragon-flies, Odonata, and the ant-lions, A7yrmeleon,
are examples of the extreme result of this tendency. And in
the Lepidoptera there are several instances where a good
series illustrating successive stages in this reduction can be

Evolution and Taxonomy 61

found. ‘Thus within a single family, or perhaps superfamily,
the more generalized members have three anal veins in at
least one pair of wings,

(usually the hind Lp aie
wings), while as one :
passes to more and
more specialized forms
only two, or one anal
veins are found.

I believe that this IX
selection of the nar-
rower winged forms is
the result of the sur-
vival of those forms
that are best fitted for VU,
rapid flight. A good Sep eoe em,
illustration of the dif-
ference in the powers
of flight between an insect with a wide anal area and one
in which this area has been reduced, can be found within
the limits of a single lepi-
dopterous superfamily, the
Zygenina. Compare the
power of flight of 77zpro-
cris (Fig. 10) in which there
are two anal veins in the
fore wings and three anal
veins in the hind wings,
with that of Syztom7s (Fig.
11) in which there is only

Fic. 10.—7yriprocris.

11 +10 a single anal vein in both
ae fore and hind wings.
Vile On the other hand, in
1X other lines of development,
Fic. 11.—Syntomis. natural selection has evi-

dently tended to a preserva-
tion of the wider winged forms ; and the widening of the wings
has taken place largely by a specialization of the anal area by

62 John Henry Comstock

addition. ‘The extreme result of this method of specialization
is presented by the Orthoptera and especially by the hind wings
of the Acrididz. Here we find a widely expanded anal area,
with regularly alternating concave and convex veins. Such a
wing is not fitted for striking vigorous and rapid blows upon the
air as is required for rapid flight ; but is adapted to a sliding
flight, a sliding up like a kite or down like a parachute. Such
a method of flight would naturally reach its highest develop-
ment in jumping insects, like the Acridide.

A study of the illustrations just given shows that where the
tendency of natural selection is towards the development of a
rapid flight there is usually a cephalization of the function of
flight, z. e., the hind wings are greatly reduced, and the fore
wings become the chief organs of flight. ‘This is well shown
by the more specialized Zygzenids (Fig. 11) ; and the extreme
of such a cephalization is presented by the Diptera. That
such a cephalization is not absolutely necessary to rapid flight
is shown by the dragon-flies (Odonata) ; but here the abdo-
men is greatly elongated, which gives a similar result.

On the other hand where an expansion of an anal area has
taken place in order to provide for a sliding flight, it is the
hind wings that are specialized by addition, z. e., the opposite
of cephalization takes place. The Acrididz have already
been cited as an illustration of this.

The region lying between the subcostal and anal areas is
traversed by three principal veins and their branches. ‘These
veins as already indicated, are the vadzus, media and cubztus,
the radius lying next to the subcosta, the cubitus next to the
anal area, and the media, between the radius and cubitus.
Very remarkable modifications take place in the structure of
these veins and in their relation to each other. Some of the
modifications will be discussed in detail later ; in this place I
wish only to make some very general statements.

If a large series of wings be examined it will be found that
the area of each of these veins may be specialized either by
addition or by reduction, z. e., it may be either widened or
narrowed. When the tendency of natural selection is to
widen one of these areas, the points of origin of the branches

Evolution and Taxonomy 3

of the principal vein will be nearer the base of the wing in the
more specialized forms than in the more generalized members
of the same group. On the other hand when the tendency of
natural selection is to narrow one of these areas the branches
become consolidated with the main stem to a greater and
greater distance from the base in the more and more special-
ized forms. This consolidation of a branch with the main
stem or of two branches with each other may extend to the
margin of the wing, and thus the number of branches be re-
duced. This migration of the point of origin of a branch of a

= Ix VI

Fic. 12.—Prionoxystus ; f. frenulum and frenulum brace, enlarged.

vein often affords an excellent clew to the degree of departure
from a more generalized type.

But the most remarkable of the changes which take place
in this region of the wing is an abortion of the main trunk of
media and a consequent uniting of the branches of this vein
either with cubitus or with both cubitus and radius. Ex-
cellent illustrations of this occur inthe Lepidoptera. In many
of the more generalized moths the main trunk of media is well
preserved (Fig. 12); while in more specialized forms it is en-

64 John Henry Comstock

tirely wanting. Sometimes, as in Danazs, remnants of the
basal part of the branches of media project back into the dis-
cal cell from the discal vein (Fig. 13) ; while in many other
butterflies the branches of media are so completely united with
radius and cubitus that there is no indication of the fact that
they do not belong to these systems of veins (Fig. 14).

It is probable that in none of the Palzeodictyoptera were the
wings plaited, as they are in many existing insects ; although

S og Oe ag
1 ' Te Tr : Wiese

Fic. 13.—Fore wing of Danazs.

in some, they were broadly folded. And if we except the
anal furrow (vein VIII), already referred to, all of the veins
were of the type that is termed convex; that is, they were
more prominent on the upper surface of the wing than on the
lower.

We thus see that the evidence of the Paleeodictyoptera does
not corroborate the theory of Adolph and Redtenbacher as to
the primitive type of the wings of insects. Instead of the
primitive wing consisting of regularly alternating concave and
convex veins, as described by them, it is probable that the
concave veins are a later development, either arising de novo or
being modified convex veins, excepting always the anal fur-
row (vein VIII), regarding the origin of which we know
nothing.

Concave veins have evidently arisen to meet two distinct
needs: first, in those insects in which the wings have become

Evolution and Taxonomy 65

J

broadly expanded so as to provide for a sliding flight, there is
a necessity for the plaiting of these wings when not in use so
that they may be carried without impeding locomotion on foot ;
second, we find in certain cases where the tendency of spec-
ialization has been towards a narrowing of the wings in order
to admit of vigorous flight, a corrugation of the wings has
taken place in order to strengthen them. The hind wings of
a grasshopper illustrate the first ; and the wings of a dragon
fly present the extreme of the second form of specialization.
It is easy to see that a
corrugated wing, like that
of the dragon fly, is much
stiffer than it would be if
the membrane extended in
asingle plane. If one will
examine the cross veins ex-
tending between the costa
and the radius in a dragon
fly, he will find that some
of these are in the form of
triangular braces which ef-
fectually prevent any ten-
dency on the part of the
wing to become flattened.
Evidently the corrugation
is of extreme importance.
The concave veins have
arisen in two ways. The
first of these is by a change
in the position of a convex Fic. 14.—Paphia.
vein. The subcosta in
most of the orders of insects is an illustration of this. In
the Lepidoptera the subcosta has retained its form as a
convex vein, but in most orders of insectst he area be-
tween the costa and the radius has been depressed forming a
furrow along the bottom of which the subcosta extends. This
corrugation has resulted from the need of a stiffening of the
costal edge of the wing. The second method of formation of

66 John Henry Comstock

concave veius is illustrated by a vein that lies between radius
and media (vein IV), and also by a vein that lies between
media and cubitus (vein VI) in certain orders of insects.
These veins (IV and VI) I do not believe existed in the Pale-
odictyoptera ; at least, I have not been able to find any indi-
cation of their presence in the figures of paleozoic insects.
In the more modern orders of insects when a corrugation of
the wings arose, and the areas traversed by these veins be-
caine depressed, veins IV and VI appeared. It is probable
that they were developed by a straightening out of the zigzag
line between two series of cells. ‘This can be readily seen by
comparing the wing of one of the devonian may flies (Plate III,
3) with that of a modern may-fly (Plate III, 5). In the devoni-
an may-fly the cells of the wing are polygonal, while in the
modern may-fly they are quadrangular. In the latter case
not only have longitudinal concave veins been formed from
zigzag lines, but the cross veins extending between these con-
cave veins and the adjacent convex veins have become strictly
transverse. An arrangement which insures the preservation
of the corrugations.

In a similar way the concave veins in the anal area of the
modern Orthoptera have probably arisen.

I conclude, therefore, that in the more highly specialized
wings of certain orders of insects, there exists a regular alter-
nation of convex and concave veins, this alternation being the
result of a corrugation ot the wings for the purpose of stiffen-
ing them. This conclusion is quite different than that
reached by Redtenbacher, who starts with the fan type of
wing as the primitive one.

In the Lepidoptera this corrugation has not taken place, the
wings being stiffened by scales, consequently, the subcosta
remains a convex vein, and veins, IV and VI have not been
developed. It is probable that these veins are also lacking in
the wings of the Hymenoptera and the Coleoptera, but I have
not studied carefully the wings of these insects.

As to the nomenclature of the wing veins of insects, there
is no longer any doubt regarding the desirability of a uniform
system of naming the veins in the different orders of winged

Evolution and Taxonomy 67

insects. Only by sucha system can those comparisons be
made which are necessary in any thorough study of the rela-
tionship of the orders to each other. Heretofore the students
of each order have had their peculiar nomenclature, and in
many cases writers treating of a single family have proposed
a set of names to be used in that family alone. The matter
has been further complicated by the fact that not only have
different names been applied to the same vein, but the same
name has been applied to different veins. Thus the terms
costa and subcosta have been applied by Lepidopterists to
different veins than those that bear these names in other orders.

There have been several attempts to establish a uniform
nomenclature. Of these that of Redtenbacher is the most im-
portant, being based on a much more extended study of the
subject than that made by any other author.

Redtenbacher was the first one to work out a system and
apply it to all of the orders of winged insects. And although
his system was based on what I believe to be a false theory,
and his interpretation of facts in some cases were faulty, I be-
lieve that the more essential features of his system can be
adopted.

Although, as I have pointed out above, the fan-type of
wing was not the primitive type, it seems desirable to base
our nomenclature on this type ; for here we find the maximum
number of veins ; and our nomenclature should include the
secondarily developed veins of modern insects as well as the
primitive veins.

I bave shown that in the preanal portion of the wing of
paleozoic insects there were developed five principal veins.
These may be designated, beginning with the one on the
costal margin of the wings, as costa, subcosta, radius, media
and cudbitus. ‘The term media was proposed by Redtenbacher;
the others were adopted by him as those sanctioned by the
best usage.* I have also shown that in certain insects there

* Redtenbacher was not the first to recognize media asa principal
vein. This was done by Edward Doubleday nearly fifty years ago. See
his Remarks on the Genus Argynnis, Trans. Linn. Soc. Vol. XIX,
1845. Ihave adopted the term medza in preference to discoidal vein
proposed by Doubleday as the latter might be confused with discal vein,
the term commonly applied to certain cross veins.

68 John Henry Comstock

is developed, secondarily, a longitudinal vein between radius
and media, for this I propose the term premedia ; and also in
the same insects there is developed a longitudinal vein be-
tween media and cubitus, this I designate as fostmedzia.

Following the system of Redtenbacher these veins may also
be designated by Roman numerals. ‘The equivalence of the
numbers and names of the veins of the wing is indicated by
the following table ; also the nature of the veins.

T.—- Costar ase convex.
II.—Subcosta, usually concave, secondarily.
IT} —Radnrs a. ae convex.
I1V.—Premedia . . . . concave.

Vi—Mediaiinis kuce le convex.
VI.—Postmedia. . . . concave.

Vie —_Cibitusianseeaeee convex.
VIII.—First anal . . . . concave.
IX.—Second anal. . . convex.

X.—Third anal. . . . concave,

ef al.

It will be seen from this table that if we consider subcosta
a concave vein, which it has come to be in the larger num-
ber of the orders of insects, there is a regular alternation of
convex and concave veins, when the maximum number of
veins is present. And hence the convex veins are desig-
nated by odd numerals and the concave veins by even numer-
als ; this is one of the chief features of Redtenbacher’s system,
and an exceedingly useful one.

If this system be applied to the anal area, and I believe it
is best that it should be, all convex anal veins must be desig-
nated by odd numerals. In those orders where the anal area
has been greatly specialized by addition, (e. g., Orthoptera),
this would naturally follow ; for there we find a regular alter-
nation of concave and convex veins. But in certain other
cases it is not so obvious. In those Lepidoptera in which
three anal veins are preserved, the first (vein VIII) is con-
cave, and doubtless represents the primitive anal furrow ; the
second is convex and is obviously vein IX ; but the third is
also convex! Shall this be designated as vein X, or as vein
XI? It seems to me better that we consider vein X absent,

Evolution and Taxonomy 69

as are veins IV and VI in this order, and designate this one
as vein XI. ‘This view is strengthened by the fact that in
many of the Microlepidoptera with broad hind wings there is
a prominent fold between the two convex anal veins. This
fold may be looked upon as the beginning of an anal vein,
which is as yet undeveloped, but which if developed would
be vein X.

Another important feature of Redtenbacher’s system is the
designating of the branches of a vein by Arabic indices ap-
pended to the Roman numeral indicating this vein. Thus
the branches or radius are designated as III,, III,, III, etc.,
(Fig. 15).

While I believe that
we are able to trace out
homologies between
the principal veins of
the wings of insects of
the different orders, I
do not think it prac-
ticable, even if possi-
ble, which I doubt, to
homologize the dranch-
esoftheprincipalveins -
beyond the limits of a
single order. I have
not, therefore, adopted
in all cases Redten-
bacher’s plan of using
odd indices only for
convex branches and
even indices only for
concave _ branches.
This plan will be found
very useful in those
orders (e. g., Ephemer- Fic. 15,—Castnia.
ida) where the fan-type
of wing has been developed ; but in other cases (e. ¢., Lepidop-
tera) it would merely complicate the nomenclature without ad-

Ills

70 John Henry Comstock

ding toits value. Thusin the Lepidoptera I designate the five
branches of radius as III,, III,, III,, III,, and III, respectively,
although all of these branches are convex.

It should be noted that in numbering the branches of a
principal vein, they are numbered in the order in which they
reach the margin of the wing, not in the order in which they
are given off from the main stem. The system adopted is not
only the simpler but insures the same number being applied
to homologous veins in different genera, which would not be
the case were the other system adopted.

Having indicated the more general features in the develop-
ment of the wings of insects in order to define the nomen-
clature of the wing veins that I have adopted, and having
explained this nomenclature, I can now pass to the considera-
tion of certain details exhibited by the wings of the Lepidop-
tera.

The more important of these are the changes which take
place in media; for this vein in the Lepidoptera is of the high-
est value for taxonomic purposes.

The tendency to abortion of the main trunk of media has
already been pointed out. The explanation of this tendency
I have not fully determined satisfactorily to myself, I can
only suggest the following: In the course of the narrowing
of the wing and the strengthening of the main veins which
has taken place as a result of a natural selection of the more
active flying forms, the veins have become crowded together
at the base of the wing. ‘The more important veins, 2z. e¢.,
radius and cubitus, have held their place, while media has
been crowded out. ‘This crowding out has probably taken
place in this wav. ‘The narrowing of the space occupied by
media compressed the large trachea or tracheze which it con-
tained. Such a compression tends to shut off the supply of
air to that part of the wing supplied by the branches of media.
To counteract this evil, communication is established between
the branch of media and the veins lying on either side of it.
When such a communication is well established there is no
longer any need for the basal portion of media and it becomes
atrophied. Inthis connection it should be stated that the mem-

Evolution and Taxonomy 71

brane of the wing is supplied with an immense number of mi-
nute trachez extending from the main trunks contained in the
veins. The lateral branches of the tracheze are rarely seen
even in carefully bleached wings, for in mounting the speci-
men they become filled with the mounting medium and are
thus rendered invisible. But occasionally air will remain in
them rendering them distinctly visibly. It is by means of
some of these lateral tracheze that the branches of media be-
come connected with radius and with cubitus.

-When such a communication has been established it is im-
portant that these tracheze should not be compressed by the

04 MH: Tle

IX VI
Fic. 16.—FPackardia.

bending of the wing during flight, therefore any tendency to
protect these trachez by a thickening of the membrane along
their course would be beneficial and would result in the de-
velopment of veins enclosing these tracheze.

These veins at first extend in a transverse direction, and are
thus obviously cross veins (Fig. 16, ¢c. v.). But the result of

72 John Henry Comstock

farther specialization is to round off the angles in the path of
the tracheze, as the angles in our roads are rounded off by carts.
This process is continued until these cross veins become parts
of longitudinal veins, and their true nature as cross veins is
completely hidden. ‘This is well shown by the connection ex-
isting between the third branch of media (vein V,) and cubitus.
A study of the venation of Castnia (Fig. 15) shows conclu-
sively that media is three-branched and cubitus only two-
branched. Here the connection between vein V, and vein VII
is obviously a cross vein. But in every American moth and
butterfly known to me, except perhaps Hepzalis and Micropte-
ryx, the union of these two veins is so complete that there is
no hint of the fact that vein V, is not a branch of vein VII.
And in several families vein V, has also become united with
vein VII in a similar manner. ‘The result is that cubitus (the
median vein of many authors) is described as three-branched
in some families and four-branched in others.

Two years after I had reached the conclusion that media is
three-branched and cubitus only two-branched in the Lepi-
doptera, Spuler published a paper* in which these facts are
demonstrated in an entirely different way. As I did not pub-
lish my conclusions, the credit of the discovery belongs of
course to Spuler. I wish merely to state that my conclusions
were reached independently of that author’s work, and by an
entirely different method. I was led to the correct under-
standing of the relation of these veins by a study of existing
generalized forms (especially FHfepfialis and Castnia); while
Spuler’s conclusions were based on a study of the ontogeny of
certain butterflies. He found that in newly formed pupe the
trachea which later becomes enclosed by media is three-
branched, while that one which is the precursor of cubitus, is
only two-branched. This is an interesting instance of the
evidence of ontogeny confirming results obtained in an effort
to determine the phylogeny of a group by the study of gener-
alized forms.

* A Spuler.—Zur Phylogenie und Ontogenie des Fliigelgedders der
Schmetterlinge. Zeit. fur wissenschaftliche Zoologie, LIII.

volution and Taxonomy 73

Let us see how the facts regarding the changes of media can
be used in taxonomic work.

First, the presence of the main trunk of media is an indica-
tion of a generalized condition. This at once throws light on
the position of the Megalopygidz, the Psychide, the Cosside,
the Limacodide, and certain of the Zygaenina. ‘These fami-
lies are evidently much nearer the stem form of the Lepidop-
tera than are those families in which media has been lost.

It does not follow that these families should be classed to-
gether. For each one may represent a distinct line of devel-
opment. ‘The presence
or the absence of the I, Ula
base of media is a char-
acter that merely indi-
cates the degree of di-
vergence from a primi-
hive: ‘type ‘(seeps 43)
The divergence in each
case may be along a dis-
tinct line. It may be
worth while to state in
this connection that the

families named above } HE
are nearly all of those of Va
the Macrofrenate in Va
which three anal veins V;
are preserved in the hind XI VO
wings, another character oy ve

indicating a compara-
tively slight degree of
divergence from the primitive type.

Correlated with the abortion of the base of media is the
coalescence of its branches with the adjacent veins. It fol-
lows from this that the extent to which this coalescence has
gone is an indication of the degree of departure of a form
from the primitive type. Compare, for example, the hind
wings of Packardia (Fig. 16) with the hind wings of Adoneta
(Fig. 17), two genera of the family Limacodide. In Packar-

Fic. 17.—Adoneta.

74 John Henry Comstock

dia, where a remnant of the base of media still persists, vein
V, is merely connected with vein III by a cross vein. But
in Adoneta, where the base of media of the hind wings is lost,
vein V, has become consolidated with vein III for a consider-
able distance. It is obvious that in these respects, the loss of
the base of media and the extent of the coalescence of veins
III and V,, Adoneta is the more highly specialized of the two
genera.

It often happens that after the abortion of the base of media
the discal cell is traversed by a more or ‘less distinct line or
scar indicating the former position of this part of the vein.
This scar is indicated in the accompanying figure of the
wings of Zacles (Fig. 18) by dotted lines.

It will be observed that the branches of media are not con-
tinuous with the branches of this scar. There has been a
migration of the proximal end of the remaining portion of
each branch towards the vein from which it gets its supply of
air. Frequently there remain short stumps, projecting into
the discal cell from the discal cross vein, and continuous
with the scar, at the points where the branches formerly
emerged from the discal cell. These are indicated by the
arrows in Figure 13, and are also shown in Figure 18. It
will be readily seen that the extent to which this migration
of the base of a branch has gone will serve as an indication of
the degree of divergence of the form from a primitive type.*

In connection with this part of the discussion a few words
regarding the nature of the so-called discal vein are appropri-
ate. It is evident that this is not a single cross vein extend-
ing from radius to cubitus ; but it is made up of several distinct
elements, and these elements may differ in different genera.
There is across vein between radius and the first branch of
media, and another between the third branch of media and
cubitus (Figs. 16,18, c\v4'ov.). These extremes, of the
series forming the discal vein, however, have the appearance
in many cases of being parts of longitudinal veins (Fig. 18) ;

*I wish here to acknowledge the assistance of Miss Clelia D.
Mosher, who, while a student in my laboratory at Palo Alto, first
worked out the relation of these stumps to the branches of media.

Evolution and Taxonomy 75

and in such cases have not been considered, heretofore, as
parts of the discal vein. The intermediate portions of the
discal vein may be merely the branches of media somewhat
bent out of their primitive course. This condition is illus-

TiI2+3
Ty4+5

Fic. 18.—Zacles. The hind wing is enlarged more than the fore wing.

trated by the hind wings of Packardia (Fig. 16). Here the
first branch of media has been drawn towards radius as a re-
sult of the change in the source of its air supply ; and in a
similar way the third branch of media, receiving a large part
of its air from cubitus, is bent towards cubitus. In other

76 John Henry Comstock

cases cross veins have been developed between the branches
of media, and these form part of the discal vein ; this is the
case where there is an interpolated cell in the discal cell
(Fig. 12). Sometimes a part of the discal vein may be looked
upon as a trail indicating the path along which the base of a
branch of media has migrated. An instance of this kind can
be seen in the fore wings of Zac/es (Fig. 18). Here that part
of the discal vein lying between the stump which is marked
V, and radius is the path over which the base of vein V, has
migrated.

The union of vein V, with radius and of vein V, with
cubitus after the abortion of the base of media is what would
be expected. But in which direction would one expect the
base of vein V, to migrate? Occupying an intermediate
position between radius and cubitus it may go either way. It
is like a stream in the middle of a level plain, a trifle may
change its course. And thus we find that in some families it
migrates towards cubitus, making this vein apparently four-
branched, while in other families it goes towards radius,
leaving cubitus apparently three-branched.

This difference may be looked upon as a difference in kind
of specialization, and is frequently of high value as indicating
a dichotomous division of the line of descent. It is obvious
that in a family, where vein V, has migrated far towards cu-
bitus and has thus established its chief source of air supply in
that direction, it is not probable that genera will arise in
which vein V, is more closely united to radius than to cubitus.
To resume the figure, the plain through which the stream is
flowing is an elevated plateau; a pebble may determine
which of two slopes it shall descend; but when well started
down one, it cannot traverse the other.

This character, however, must be used with care. In fami-
lies where the direction of the migration of the base of vein
V, has been firmly established, as in the Saturniidz (Fig. 18),
and in the Lasiocampidee (Fig. 29), it is decisive. One need
not hesitate a moment in determining to which of thege two
families a genus belongs. But there are other families in
which the direction of this migration is not yet fixed; and
here the character is of subordinate value.

Evolution and Taxonomy. 77

Not only may the branches of one system of veins become
joined to those of other systems as just described, but there
are many forms in which two adjacent principal veins are
coalesced to a greater or less extent. This occurs chiefly in
the hind wings.

I will discuss the veins in regular order, beginning with
costa. ‘This vein is apparently wanting in the hind wings of
most Lepidoptera,
and but little can be 2
said regarding the
manner of its disap-
pearance. It seems
probable that in most
cases it has simply
become atrophied,
the overlapping of
the wings rendering
it unnecessary oreven
undesirable. For
when that stage in
the development of
the order was reached
in which the two hind
wings of each side FIG. 19.—Zyge@na.
overlapped to a con-
siderable extent, was it not better that the costal margin
of the hind wing should be flexible? There was no longer
any need of a stiff margin, this part of the wing being sup-
ported during the downward stroke by the overlapping part
of the fore wing; while a flexible margin would act as a
valve to prevent the escape of the air between the two wings.
The two wings in this way present a continuous surface. In
many moths there is a thickening of the basal part of the
costal margin; this I believe to be the remnant of costa.

But although it seems probable that in many cases the
costa of the hind wings has simply faded out leaving cell I to
function as this costal valve, there are cases in which this
valve is a precostal development, the costa having moved

78 John Hlenry Comstock

backwards and become consolidated with the subcosta. A
good illustration of this is presented by the European genus
Zygena (Fig. 19). Here the costa and subcosta are distinct
for a considerable distance, but become united into a single
vein.

It will be observed that the basal portion of costa extends
like a cross vein and forms a
strong support for the frenulum.
This part of costa is sometimes
preserved: when the remaining
part is wanting. See figure of
Castnia (Fig. 15).

In most genera of the Geo-
metridz there is a faint indica-
tion of a remnant of costa ex-
tending from the humeral angle,
at the base of the frenulum, to
the subcosta, which is strongly
angulated. The same thing is
shown in Luphanessa, (Figs.
20, 21), which is probably a
Geometrid genus.

In many of the Psychidez a remnant of costa is preserved
(Figs. 22, 23). Here subcosta and radius are united for a
considerable distance ; then they separate and subcosta soon
becomes joined to costa for a short distance. In Figure 23 I
have represented what I believe to be the course of these
three veins, slightly separating them where they are coalesced.

That part of subcosta that lies between its
separation from radius and its union with
costa appears like an oblique cross vein ; and
had the short spur that represents the termi-
nal part of costa been lacking, its true nature
would not have been suspected. Does not Fic. 21. — Hu-
this arrangement of the veins in the Psychidze mee angle of

~ 1ind wing of
afford an explanation of the origin of the so- Awphenessa.
called intercostal vein which is characteristic of
the Sphingide? See Figure 24. In many butterflies the base

Fic. 20.—Huphanessa.

i

Evolution and Taxonomy 79

of costa of the hind wings is preserved. This is well shown in
Papilo(P1. II, 2). This vein has been observed and figured by
many writers; but it has always been considered a precostal
(2. e., humeral) vein. But I believe it is essentially different
from the humeral vein or veins of the Lasiocampidee. The hu-
meral veins of this family of moths are secondary developments ;
while the spur in the humeral angle of butterflies is a rem-
nant of one of the primitive veins, the costa.

In the hind wings of many moths a coalescence of subcosta
and: radius also
takes place to a
greater or less ex-
tent. . These two
veins may be joined
forashortdistance, 3; Z Vass
as in Packardia, at
(Fig. 16), or they
may be merged in-

II,

to one for a consid- S: :

erable proportion of II
their length as in os
Megalopyge, (Fig. Vang
25), and in the Sesi- vii
ide. Every degree VIb
of coalescence be- . a

tween these ex-

tremes exist.
It has been customary in cases like the last to consider the
subcostal vein wanting ; but it is only necessary to count the
branches of the principal veins to see that

Fic. 22.— Thyredopteryx.

all are present ; moreover, in most cases the
I .
fa two coalesced veins are separate for a short

u
m -
distance near the base.

aaa eS a There are, however, forms in which the
eter Thyre. basal part of radius is wanting. This con-
dopteryx. dition is brought about in this way. First,

something interferes with the growth of the
basal part of radius, and this vein becomes weaker than the oth-

80 John Henry Comstock

er principal veins. This stage is exhibited by Prionoxystus,
(Fig. 12), in which radius of the hind wings still persists but is
much weaker than the other véins, except media. Correlated
with this weakening of radius is the formation of a cross vein
between it and subcosta (Fig. 12, ¢. v.). This is an estab-
lishment of a new source of air supply for the distal portion of
radius, and renders less necessary the basal portion of that
vein. Sometimes the two veins are drawn together, and the

M11, 2

t+ UT

II
lr

VIly

XI VII2

Ix

Fic. 24.—Protoparce.

coalescence extends in both directions from the point of first
union, resulting in the form presented by JZegalopyge (Fig.
25); but in other cases that portion of radius between the
point of union and the base of the wing becomes atrophied.
An approach to this condition is shown by Acolozthis (Fig.
26).

In the fore wings where radius is branched, we often find
an anastomosing of the branches. In this way are formed
the accessory cells (Fig. 20). This anastomosing doubtless
serves to strengthen the wing.

Evolution and Taxonomy 81

In the hind wings of all Lepidoptera, except Hlepzalis (Fig.
27) and Micropteryx (Fig. 28), all of the branches of radius
are united into one. But the condition of radius in the two
genera named shows that it is normally five-branched in the
hind wings as well as in the fore wings.

In the discussion of media, given on a previous page, atten-
tion was called, so far as concerns its coalescence with other
veins, merely to its branches; but the principal stem of this
vein may become joined either to radius, as in the fore wing
of Castnia (Fig. 15), or to cubitus, as in the fore wing of
Prionoxystus (Fig. 12).

It will be observed that here is a character which is of value
as indicating a dichotomous division of the line of descent.

I do not recall any instance where cubitus is coalesced with
an anal vein to a marked degree, except in the Papilionidze
(Pla Eiabio. 2) > but the
growing together of dif-
ferent anal veins is a
very common occur-
rence. This condition
is preceded phylogenet-
ically by the formation
of a cross vein. Such
a vein exists between
veins IX and XI of the
fore wings of Castnia
_ (Fig. 15), and between

veins VIII and IX of

{fl

Thyridopteryx (Fig.22). i
Following this stage the if
two veins are drawn to- its
gether, See veins IX a Mon

and XI of the fore wings IX VIL
of Thyridopteryx (Fig.
22), aud the same veins
in Megalopyge (Fig. 25). Usually, however, when these veins
are joined in this way, that part of vein XI beyond the point of
union disappears, and vein IX presents the appearance of
being forked towards the base. See Adoneta (Fig. 17).

FIG. 25.—Megalopyge.

82 John. Henry Comstock

In the fore wings of the Psychidee it frequently happens
that the basal part of vein VIII disappears, and then vein IX
appears to be forked outwardly (Fig. 22).

A good illustration of the coalescence of principal veins in
another order of insects is presented by the dragon-flies (Odo-
mata). Here veins III, IV and V are united into one from
the base of the wing to the arculus. This coalescence is from
the base of the wing outward, as is the coalescence of the
main stem of media with either radius or cubitus in the Lepi-
doptera. But most instances of coalescence in the Lepidoptera

begin on the disc of the

ae ee, wing and extend in

either direction. In
the Diptera a_ third
mode of coalescence is
common. In this order
it frequently happens
that two longitudinal
veins come together at
their tips and unite, the
coalescence proceeding
VUy from the margin of the

tx vir Vi wing towards the base.
ae GA calories. The result is that a cell

which normally opens

on the margin of the wing is closed at a greater or less distance
before the margin ; and the extent of this distance will be an
indication of the degree of divergence from the primitive type.

The coalescence of two veins may be complete resulting in
the reduction of the number of veins in the wing. This fre-
quently happens especially with the branches of radius of the
fore wings in the Lepidoptera. This vein is naturally five-
branched ; when. a less number of branches occurs it is because
the coalescence of some of the branches has proceeded to
the margin of the wing.

The number of veins in the wing may be reduced, however,
in another way : a vein may simply fade out. The most com-
mon instances of this kind in the Lepidoptera occur in the

Evolution and T. axonomy 83

anal areas of the wings. As these areas become narrowed
(z. €., specialized by reduction) one or two veins disappear.

The second branch of media is also a vein that is apt to
disappear by atrophy ; this occurs frequently in the Geomet-
ride.

The usual result of specialization of the wings of Lepidop-.
tera is a reduction of the number of veins where any change
in the number is made. But it is not always so; for new
veins may appear. I have already described the formation of
cross veins, where a new source of air supply is established,
and preceding the coa-
lescence of distinct Dm,
veins. In a somewhat
similar way veins are
formed in the basal part
of cell I of the hind
wings in the Lasiocam-
pide. In these cases
the humeral angle has
become greatly extend-
ed (Fig. 29). This out-
growth of the wing, like
all other parts, is abun-
dantly supplied with Fic. 27.—Hepialis.
trachee ; and about
some of the trachez have been developed veins which protect
them by stiffening this area so that it will not bend and thus
compress them. This stiffening of the area doubtless serves
another function to be described later.

These veins, developed in the humeral angle of the wing, I
designate as the humeral veins. They have been termed. the
precostal veins; but the determination of the fact that the so-
called costa of Lepidoptera is really the subcosta, renders the
name precostal inappropriate.

The joining together of the two wings of each side in many
moths by means of a frenulum and a frenulum hook, is a well
known characteristic. But the real nature of the frenulum
has not been understood, neither has its taxonomic value been
appreciated.

VIlz_ Vis, ¥2°

84 John Henry Comstock

I was led to make a careful study of this part of the wing
by the discovery that in /Zepzalzs an entirely different method
of uniting the two wings of each side has been developed. In
this genus, and as I have since discovered in Micropteryx
also, instead of the wings being joined by a frenulum, which is
a bristle or a bunch of bristles borne by the hind wing, they
are joined by a membranous lobe extending back from near
the base of the inner margin of the fore wing (Fig. 27, 28, j).

To this lobe I have applied the name jugzz.

When the wings of Hepzalis are extended, the jugum pro-
jects back beneath the costal border of the hind wing, which,

Sa ae

EEE?

3 I,

IIT,

Vv
WIE Vilavar- Yai

Fic. 28.—Micropteryx.

being overlapped by the more distal portion of the inner mar-
gin of the fore wing, is thus held between the two, as ina
vice.

The discovery of the fact that there are two distinct modes
of uniting the wings during flight suggests the inference that
in the primitive Lepidoptera the wings were united in neither
way. For it is not easy to see how one mode could have been
developed from the other.

It is probable that in the primitive moths the mesothorax
and metathorax were much more distinct than in the recent
forms ; and consequently the two pairs of wings were farther

Evolution and Taxonomy 85

apart than now. As the consolidation of the thoracic seg-
ments advanced, the wings were brought nearer and nearer
together, till finally the development of a connecting organ
was rendered possible.

Such an organ might be borne by the fore wings, or it
might be borne by the hind wings. In some moths the spe-
cialization took the former direction; in others, the latter ;
and thus arose a division of the order.

This division I consider of subordinal value ; and I have al-
ready proposed the names
Jugate and Frenate for the

suborders thus indicated.* Hh Ills
Let us try to obtain an Va

idea of the ways in which Tl ue

the jugum and the frenu-

lum were developed. As V3

to the jugum I have but
little to offer beyond the
suggestion that at first it VIlz
may have been merely an Ix
adventitious lobe, or a
slight sinuosity in the in- Mi
ner margin of the fore Va
wing. If such a lobe
should project beneath the
hind wing ever so little it Vili
would tend to insure the

synchronous action of the a

two wings, and thus offer be

an opportunity for natural FIG. 29.—Clisiocampa.
selection to act.

The frenulum is a much more complicated organ. As a
rule we find that in the female it consists of several bristles,
while in the male it consists of a single, strong spine. If one
of the bristles of the compound frenulum of the female be ex-
amined it will be found to be hollow, containing a single cav-
ity. But when the frenulum of a male is examined it is found

* Proc. Am. Ass, Adv. Sci., Vol. XLI (1892), p. 200,

86 John Henry Comstock

to contain several parallel cavities. Evidently the frenuium
of the male is composed of several bristles as is that of the
female, but these bristles are grown together, forming a single
strong spine. This can be easily seen by examining a
bleached wing that has been mounted in balsam. Usually
the cavities in the bristles contain air which renders them
easily visible.
It is obvious, therefore, that the frenulum of the female ex-
hibits a more generalized condition than does that of the male.
In some females the frenulum
is so slightly developed that the

is pristles composing it are little

Vy :
more than hairs. ‘This fact sug-
y gests that the primitive frenu-
Va lum was developed from a bunch
oe of hairs, clothing the base of the
wing. Suchatuft of hairs pro-
Nz jecting under the fore wing
1x would tend in a slight degree

to insure the synchronous ac-
tion of the two wings; and as
soon as these hairs had assumed
this function the tendency of
natural selection would be to
strengthen them. In the fe-
male of Prionoxystus the frenu-
lum consists of a series of bris-
Fic. 30.—Anisota. tles whick vary in size from a
short hair to a comparatively
long spine (Fig. 12, f). This throws much light on the de-
velopment of this organ.

The extent to which the specialization of the frenulum has
been carried is remarkable. In the males of some of the Psy-
chidze it is a strong spine nearly half as long as the hind wing
(Fig. 22). In the Cymatophoride it is furnished with a knob
at the tip. But the most remarkable feature of this speciali-
zation is the development of a membranous fold on the fore
wings of males for receiving the end of the frenulum, and thus
more securely fastening the two wings together.

Evolution and Taxonomy 87

This fold, or frenulum hook, is so well known that it is un-
necessary toenter upon a detailed discussion of it. I will,
therefore, merely record a few observations that I have made
upon it. In all families in which I have observed it, it arises
trom the membrane of the wing near the base of cell I (Fig.
22), except that in
Castnia it seems to Th
have been pulled
back so that it arises
from the subcostal
vein. The wunifor-
mity in the position
of the frenulum
hook indicates that
it was developed be-
fore those families
in which it exists
had become separ-
ated phylogenetic-
ally. For if it had
been independently
developed in the
different families
there would proba-
bly have been a lack
of uniformity in its
position.

Some light is Fic. 31.—Perophora.
thrown upon the
probable origin of the frenulum hook by the fact that in many
females there is a tuft of curved scales projecting back from
the base of cell I, and serving to hold the frenulum in place.
In many moths there is also a tuft of scales projecting forward
from the base of cell VII, which functions in a similar way.

In certain families of moths (Saturniina, Lasiocampidee, and
Drepanidze) and in all butterflies there is neither a frenu-
lum norajugum. But in other respects the wing characters
of these moths and of butterflies agree quite closely with those

88 John Henry Comstock

of the frenulum-bearing moths, and do not agree with the
Jugatee in their distinctive characters (2. e., in an equal reduc-
‘tion of the two pairs of wings, and in having radius of the
hind wings branched).

If the wings of one of these moths or of a butterfly be ex-
amined it will be seen that there is a large expansion of the

FIG. 32.—Sericaria.

humeral angle of the hind wings (Fig. 30, 14), which causes
the two wings of each side to overlap to a much greater ex-
tent than they do in other Lepidoptera.

This extensive overlapping of the wings effectually insures
their synchronous action without the aid of a frenulum, and
I believe explains the loss of the frenulum. This theory is

Evolution and Taxonomy 89

supported by the fact that in the more generalized genera of
the Saturniina (Pevophora and Sericaria) where the humeral
angle is not expanded to so great a degree as it is in the more
specialized forms, there remains a rudiment of the frenulum,
(Figs. 31, 32). And in the Drepanidee where the frenu-
lum is usually wanting, it persists in one sex in certain
genera.

It is important that this expanded humeral angle should
have a certain degree of stiffness if it is to perform the func-
tion of a frenulum. ‘This has been obtained in some cases by
a more or less diffused thickening of the membrane of the
wing. Such a thickening is represented by the dotted por-
tion in the figure of the hind wing of Zacles, (Fig. 18). In
other cases the thickening takes place along a definite line
and encloses a trachea; thus are formed the humeral veins of
the Lasiocampide, (Fig. 29).

An interesting fact in connection with this abortion of the
frenulum, is that in Perophora the rudiment of the frenulum
of the male consists of a bunch of bristles. This is an excel-
lent illustration of an organ which, in the course of its abor-
tion, retraces the steps by which it was formed. In Sevzcaria
the bristles composing the rudimentary frenulum in the male
are still consolidated.

This modification of certain hairs on the costa of the hind
wing into an organ whose function is to fasten the two wings
together, is paralleled by the development of a row of hooks
on the costa of the hind wings in the Hymenoptera and in the
Aphididez, which has a similar function. And the develop-
ment of a jugum hastaken place in the Trichoptera. In fact
in several respects the Trichoptera and the Jugatee resemble
each other more closely than do the Jugatze and the Frenate.

When a careful study is made of the wings of the two sexes
of a species it often happens that a marked difference is
found in them; and so far as I have observed the difference
indicates a higher degree of specialization on the part of the
male. It seems asif the female lagged behind the male in
the race for perfection of organs. This is often shown in
the degree to which the branches of the veins are consoli-

go John Henry Comstock
dated. But it is shown most markedly in the structure of the
frenulum as already pointed out.

The explanation of this comparative lack of specialization
of the wings in females is to be found largely, I believe, in
the fact that the males seek their mates, while the females
await the approach of the males. Many instances are well
known (Orgyia, Anisopteryx, et al.) where the females
have lost their wings through disuse while the males retain
well developed wings. ‘The only instance that I can call to
mind where the reverse has occurred, is the case of Blastopha-
ga. Here the male has no need of wings, as he finds his
mate in the cavity of the fig in which he has been developed ;
while the female must fly elsewhere to deposit her eggs in a
suitable place.

The great difference in the habits of flight of the two sexes
in many moths is well illustrated by the results of a series
of experiments with trap lanterns which I conducted several
years ago. Six lanterns were kept burning from spring to
fall, and each day’s catch was kept separate. The results
have been partially tabulated by Mr. Slingerland, and I ex-
tract the following table from his report.*

TABLE SHOWING THE NUMBER OF SPECIMENS OF EACH SEX OF
"wo SPECIES OF FELTIA, CAPTURED WITH TRAP LANTERNS AT
CORNELL UNIVERSITY IN 1889.

F. subgothica. F. jaculifera.

DATE. = as ul

Males. | Females.| Males. | Females.
1G see: Soe reer y praia irme dbase ce ere’ |) co Maks I
ee IER Ace atat ott: bic ash eh SR om Arcll WiM eeth ree rare ple «ren een
US| ily eae ger ran oe mCMNA eet lide eee os acral” cipvanus.| Gilleb ence, AT ec I
ss 21 De PMI Nec gkrstitte aie ag seat ar. Neve
Wes 5 Oi Ue Bea et Nee TH «| Th erareshsdeics Seal VC ag are MIPIM ee doh
ne ZO Mav doped. Be wel toners Tal WPT rct ce CR itor cael we elt, ew Beane
CZ CRE nae St aae We eee a cee ee ha fe i voll ‘hk oc
SE ED Oe TRS rene el Cnet lari Ve TA ae el de se | ee
CENTOS ik PT, eG BP ate Gea Aa AS BR cere: tS Pata, oth SOS a
ea OGG act rege lb ore 2 Dees od kets Ae oe
BSG Oke il a ee ce 12 Po iN Ra Oe nO aad 08 |
PATO HRN some tnia tole ns Meni lee 7 Ne Wal ieee vee delle Por | secant Om
ot ZEAL leas He RCE COE etc ten) hae oie oo ileo So) cia re 2

* Canadian Entomologist, Vol. XXV, 81.

Aug. 3
oe 4
ce 5
ct 6.
“ce 7
“ce 8
ce 9
Oh 10
oe iit
sg I2
ce 14
“ee 15
Dy 16
oe 17
fCO) ATO:
ce 19
es 20
ae 27
ce 22
ins 24
“ce 25
WOM iio)
“ce 27
ee 20
“ec 29
cc 30
6c“

3I

Sept, I
“c 3
ne
oe :
ins 7
“e 8
“ce 9
ae Tor
ce 14
ts 16
“e 17
“ 18

Total

Evolution and Taxonomy gI
F. subgothica. Ff. gaculifera.
Males. \| Females.| Males. | Females.
Liege sisi: Gain ee es 9 I I OR Dae
Ride! a hee een aaes 17 2 I AL EE ST ache
A a, Ae AT ree oan 39 4 gi Pi sae Rae
SAA Wiis et hottie dean ohiseh Mendel anpieh we
ES SZ 3 BOTT Lee Mar or eS Pr eve
asec Rd eh abet te ee dh 5 tapi he les I his Saray.
PAG AEA a A 32 I Pee STAs see
apes SAWANT AH 7 I 4 SS aoe
TA Aes iia) ate oa 3 9 2 Ae BNL
SAA Se De ae 5 RR ORE REED | KAIST Pat het CUTAN MCS
Pea et oem 30 3 I 2
eA Steet 59 I 2 dp Niven ott
ae Ra ees Merits: ae Ne 42 ohcicae che chan I SANNA ot Heirs
ae: Ree ae 76 10 ee 2
EE rah.) feta 124 3 it Ye sebcle sions
Peete, heal ar 161 9 5 Se ee
Be AID cane oes 198 6 PE WOT Ce PATA SET
Noe CL Sa 160 19 I I
Meter es eae 108 6 api hahiy Tae al leh Nea oS,
63 Dida) alle? capes aerinee eek ales
PY ihn Uapieuae ke 122 10 RYE Re beaten ee
4 eS eee 209 8 Neha sie
BMAP ei heole teehee iter IIo 7 Ba aie oh Ve gl at ener
LCT ae ae eee ae go 2 SCD Cte ac tl cme Mor nec
pie Pies Aware Boece 93 3 MAAS calisy conkeeee sie
MUS es Ms Ry hex a raees 97 4 ring LPraoell Urs parte Ler Wiese
BG del Naot feta iach ch! ig 53 2 BP ar AO ea bag eae
108 GF MAS Se ane Sh oh Stns
by ja Pee ee a 60 8 sale ALN aide ey CAR
BEN east deh seni 65 2 |e A | Vg
Mh ers Sather) 50 API An lta ayia ra ee | ARMM MLS A
NEN BEE Ee 87 4 ls emcee eee ee
Me SEIS, Wey cal fe 23 oo Riad sade cotod Meret loner
A gute Mee ee Pea 37 2 Be PRN gall cee Was ts
Se eC ROP ae yee) a Mae 8 a SF ig ler Par wn! ways Oo sey. Cen ile, ler se) ames a
2 Ge eres aaa 16 3 LOT ea eat toe
SO a ie Vo a I 2) BS ee eee oe ie, See LAL se. ee oe! Oe hw
Seren 2 4e5 8) hey is, Ve I 2 en Sm) oR, ote Oplit a e fee | oF 2 ate ve
eer. ee 1s) ee em I [Set Res Oiet e S eT te Oe 6 6h aie; 20 1e, t,he Oe dy we ee)
A ly WS SA) oe ae ee 2 I COP OL) Ut Temes bt)
Ce micelle « | wt) CA's I oy OS Pee as eas te Gn i es ee aS Ole ‘el
cit 1S EMAC Rel REE aa I a! FE aS ee ee re
=i hes Gireax! 2240 142 22 9

Feltia jaculifera is not a very common species at Ithaca and
hence the results obtained with this species are not so import-

ant as those obtained with Feltia subgothica.

This is our

most common Noctuid ; and of the specimens captured (2,382

92 John Henry Comstock

in all) more than 94 per cent. were males. It isnot at all
likely that this represents the difference in the numbers of in-
dividuals of the two sexes ; it is much more probable that the
difference is due to a greater activity on the part of the males.

While I believe that the greater specialization of the wings
of the male is due to the greater activity of that sex, I confess
that I am greatly puzzled by the fact that in no female of the
Macrofrenatee has a consolidated frenulum and a frenulum
hook been developed.* In other respects the females, as a
rule, lag behind the males in their specialization only a short
distance. But while the possession of aconsolidated frenulum
and a frenulum hook is attained by the males in the most gen-
eralized of living frenate moths, that stage is not reached by
the females of the most specialized genera. Obviously there
isa factor here that I have not discovered.

A similar lagging behind of the females is showman in a
marked way in the specialization of the antennz in the Satur-
niidee. Here in the more generalized genera (Coloradia and
Flyperchiria) the antennze of the male alone are pectinate.
In Colosaturnia the female has attained pectinate antennze
but unlike those of the male each segment bears only a single
pair of pectinations. In the remaining genera of our fauna
both sexes have pectinate antennz and in each case each seg-
ment of the antennee bears two pairs of pectinations ; but the
antennze of the male aremuch more highly developed than are
those of the female. If, as seems probable, the antennz are
organs of smell, and if, which also seems probable from cer-
tain well known experiments, the males in this family are
guided to the females by the sense of smell, it is easy to under-
stand the higher specialization of the antennze of the males in
this family.

In this discussion of the taxonomic value of the wings, I
have confined myself chiefly to a study of the form of the
wings, their venation, and the relation of the two pairs to
each other. But I believe that even the clothing of the wings
is of great taxonomic value.

*I have not studied the Microfrenatze enough to be in a position to
make generalizations regarding them.

Evolution and Taxonomy 93

If the scales of any of the more generalized moths be ex-
amined, they will be found to be long and narrow and scattered
irregularly over the surface of the wing. On the other hand
in the more specialized members of the order, as in most
butterflies, the scales are much less hair-like, being short and
broad ; and they are arranged in regular overlapping rows.
Evidently both the form of the scales and their arrangement
upon the wing offer indications as to the degree of divergence
from a primitive type of the insect bearing them.

More than this I am convinced that in some cases at least
the form of the scales is characteristic of a particular line of
development. One can determine, for example, without any
doubt whether a moth belongs to the Lasiocampide or not by
merely examining the scales of the wings.

I was impressed with the taxonomic value of the scales very
soon after I began the systematic study of the Lepidoptera ac-
cording to the method outlined in this essay. But the time
at my disposal would not admit of my investigating this part
of the problem in a satisfactory manner; and at my request
the investigation has been undertaken by my colleague Pro-
fessor V. L,. Kellogg of the Leland Stanford Junior University.

Professor Kellogg is preparing an elaborate paper on this
subject, which will be published soon after the appearance of
the volume containing this one.

While the chief object which I have had before me is the
indication of a method of taxonomic work, I hope this essay
will be of value to entomologists in hastening the adoption of
a uniform nomenclature of the parts of the wings of insects,
and thus make easier the study of the relation of the different
orders of insects to each other. In order that this nomencla-
ture may be more complete I propose the following method
of naming the cells of the wing; for we have as yet no
system that is of general application.

The method I propose is, briefly, to designate each cell by
the name or number of the vein that forms its front margin
when the wings are spread.

The application of this system to the Lepidoptera is indi-
cated by Figure 33.

94 John Henry Comstock

In certain special cases special names may be desirable.
Thus in the Lepidoptera the cells formed by the anastomosing
of the branches of radius are commonly known as the accessory
cells, which is a very convenient term. And cell III + V is
universally known as the discal cell, In some of the more
generalized moths a cell is formed within the discal cell by a
forking of media: this has been termed the zz/erpolated cell
(Higsa2, 22,/27)).

In those orders where there are transverse veins, each of the
cells between two longitudinal veins is divided into a series of

‘ " 1) EL on

Fic. 33.—Fore wing of Damazs, illustrating the nomenclature of the
veins and cells. The numbers placed opposite the ends of the veins
refer to the veins ; the others, to the cells.

cells, and can be so designated. Thus the series of cells be-
tween veins III, and III, may be termed the first series of radial
cells ; and the members of such a series can be numbered. If
one should speak of the peculiar form of the third cell in the
second radial series, there need be no difficulty in determining
the cell indicated, even by one who had not madea special
study of the order to which the insect in question belongs.
Heretofore it has been necessary for the student to learn a dis-
tinct nomenclature for each order, and in some cases for each
family, studied.

In concluding this part of this essay I wish to refer to two
curious methods of specialization that have interested me

Evolution and Taxonomy 95

greatly. In certain cases where the body of the insect has be-
come greatly reduced in size, a reduction of the area of the
wing membrane has taken place and correlated with this there
has been a great expansion of the fringe of the wing. The
best known examples of this are the narrow-winged Tineids,
the Thysanoptera, and certain parasitic Hymenoptera. ‘This
kind of specialization seems possible only with minute in-
sects, where the weight to be supported during flight is not
great.

In a Tineid which I have studied the hairs composing the
fringes of the wing are inserted in the lower side of the wing-
membrane a short distance back from the edge of the wing ;
and the edge of the wing is stiffened above by strong over-
lapping scales. This arrangement renders the fringes rigid
during the downward stroke of the wing, but admits of their
depression during the upward stroke; a combination well
adapted to facilitate flight.

The second method of specialization referred to above is the
loss of the front wings in the Coleoptera and Euplexoptera. In
these two orders the paraptera of the mesothorax have been
developed into elytra, and have crowded out the front pair of
wings. The function of flight has been relegated in this way
to the hind wings.

This homology of the elytra of beetles with the tezulae of
Hymenoptera and with the patagia of Lepidoptera was point-
ed out by F. Meinert long ago* ; but Meinert’s paper seems
to have escaped the attention of entomologists almost entirely,
It is referred to by C. Hoffbauer in his paper on the minute
structure of the elytra.t But although Hoffbauer shows
conclusively that the structure of the elytra resembles that of
the pronotum and differs in every essential feature from that
of the wings, strangely enough he does not accept the conclu-
sion of Meinert.

Meinert also pointed out the fact that in many Coleoptera
(e. g., Dytiscus) rudiments of the front wings exist beneath
the elytra.

* Entomologisk Tidskrift, 1880, 168.
¢ Zeit. Wiss. Zool., LIV, (1892,) 579.

96 John Henry Comstock

As to the cause of this strange specialization I can only con-
jecture that in the primitive Coleoptera the habits of the
insects were such that the protection of the wings by elytra
was of more importance than that the first pair should be
functional ; cephalization was sacrificed in order that the re-
maining pair of wings might be protected. It may be that
the primitive Coleoptera were wood borers, the only paleozoic
remains supposed to be of beetles are borings ; or their habits
may have been like those of the recent Carabidee. In either
case the wings would be in need of special protection.

PARI SW:

_A CONTRIBUTION TO THE CLASSIFICATION OF THE
LEPIDOPTERA.

In this place I purpose to state briefly the conclusions that
I have reached regarding the phylogeny of the families of the
Lepidoptera. ‘These conclusions are the results of an effort
to read the record of the action of natural selection as recorded
in the wings of these insects. Owing to the limited time at
my disposal, but little attention has been given to the evi-
dence presented by other parts of the body ; and for the same
reason I have been able to study the Tineids, Tortricids, and
Pyralids hardly at all. ‘The following classification is, there-
fore, merely a provisional one; and is put forth chiefly as a
record of the results that I have obtained up to this time in
applying the method outlined in the preceding pages.

I confidently expect, however, that the principal conclu-
sions stated here will be confirmed by a study of other parts
of the body ; for in Nature’s court the testimony of different
witnesses if rightly understood will agree. If any of the con-
clusions should prove to be incorrect, the fault will be
found to lie with the translator and not in the record.

The fullness of the discussion that has already been given
of the ways in which wings are modified will warrant consid-
erable condensation in the following outline. I will first in-
dicate the relations of the proposed divisions to each other by
means of a table; and will afterwards give fuller characteriza-
tion of these divisions.

Evolution and Taxonomy 97
TABLE OF PROPOSED DIVISIONS OF THE LEPIDOPTERA.

A. Suborder Jucara.
B. The Macrojugate . : . Family HePrarip#.
BB. The Microjugate.. . . . Family MICROPTERYGIDA.
AA. Suborder FRENATA.
B. The Microfrenate.

Co PRA Mer eTs sree rs Sh hr eS . Superfamily Trnerna.
CO lke Tartriaie . Superfamily Torrricina.
COC Lhe Pyralids... . Superfamily PyRALIpIna.

BB. The Macrofrenate.
C. The Frenulum-conservers.

D. Moths in which the reduction of the anal area
of the hind wings precedes the reduction of the anal
area of the fore wings. This group is not repre-
sented in the North American fauna. Castnia (Fig.
15) will serve as an illustration,

DD. Moths in which the reduction of the anal area of
the fore wings precedes the reduction of the anal
area of the hind wings.

E. The Generalized Frenulum-conservers.
F. Moths in which a great reduction of the sub-
costal cell of the hind wings is taking place.

G. Moths in which the anal veins of the fore
wings anastomose so as to appear to be
branched outwardly. (Fig. 25.)

Family MEGALOPYGID&.

GG. Moths in which the anal veins do not
anastomose in such a way as to appear
branched outwardly.

Superfamily ZyGatnrna (in part).
FF. Moths in which the subcostal cell of the hind
wings is not greatly reduced.

G. Moths in which the anal veins of the fore
wings anastomose so as to appear to be
branched outwardly. (Fig. 2).))

Family Psycuip2#.

98

John Henry Comstock

GG. Moths in which the anal veins do not
anastomose in such a way as to appear
branched outwardly.

H. Family Cossipé&.
HH. Family LIMACODID.
EE. The Specialized Frenulum-conservers. .
F. DIOPTIDA.
FF. Zhe Geometro-Bombycids and the Geometrids.
G. Family NOTODONTIDA
GG. Family BREPHIDA.
GGG. Family GEOMETRIDA.
FFF. Zhe Noctuo-Bombycids and the Noctuids.
G. Family CyMATOPHORID.
GG. Family NocTuip&.

Family LIPARID.
Family AGARISTIDA.

Family ARCTIIDA.
FFFF. Jsolated Families of Specialized Frenulum-

CONSCYUEFS.

G. Family SESIIDA.
GG. Family THyYRIDIDA.
GGG. Family SPHINGIDA.
GGGG. Superfamily ZYGANINA.

CC. The Frenulum-losers.
D. The Frenulum-losing Moths.
E. Moths in which cubitus is apparently three-

branched. Superfamily SATURNIINA.
EE. Moths in which cubitus is apparently four-

branched.

F

Family DREPANIDA.
FF. Family LASIOCAMPIDA.
DD. 7he Skippers.—‘‘ Butterflies ’’ in which all of the
branches of radius of the fore wings arise from the
discal cell. Family HESPERIDA.
DDD. 7he Butterflies.—Butterflies in which some of
the branches of radius coalesce beyond the apex of
the discal cell.
E. Butterflies in which cubitus of the fore wings is
apparently four-branched. Family PAPILIONIDA.

Evolution and Taxonomy 99

KE. Butterflies in which cubitus is apparently three-

branched.
F. Butterflies exhibiting no tendency to abortion
of the fore legs. Family PIERIDA.

FF. Butterflies exhibiting a marked tendency to
abortion of the fore legs.
G. Family Lycanipé.
GG. Family NyYMPHALID.

A. SUBORDER JUGATA

This suborder includes those moths in which the two wings
of each side are united by a membranous lobe, the jugum,
borne at the base of the inner margin of the fore wings (Fig.
27, j), and in which the anal area of the hind wings is reduced
while the radial area is not. The most available recognition
character is the similarity in venation of the two pairs of
wings ; radius being five-branched in the hind wings as well
as in the fore wings.

B. THE MACROJUGATA.

Moths of medium or large size. The mouth-parts are
aborted, and correlated with this there persists a comparatively
generalized condition of the wings, which is shown by the
absence of ajugum plate. The larvee are wood-borers. This
division is represented by a single family.

Family HEPIALIDA.

BB. THE MICROJUGATAS.

Moths of minute size. Mouth mandibulate, with both
mandibles and maxille fitted for mastication. This is doubt-
less the most generalized form of mouth-parts preserved in
this order. Correlated with the presence of functional mouth-
parts, these moths show a higher specialization of wing
structure than exists in the Hepialidz ; there being a plate-
like organ at the base of the costa of the hind wings, the
jugum plate, and aseries of spines ; both of which act with the
jugum in assuring the synchronous action of the two pairs of

100 John Henry Comstock

wings. (Fig. 28). The larve are leaf miners. This divi-
sion is represented by a single family.

Family MICROPTERYGID&.

AA. SUBORDER FRENATAS.

This suborder includes those moths and butterflies in which
the two wings of each side are united by a frenulum, borne at
the base of the costal margin of the hind wings, or by a sub-
stitute tor a frenulum, a large humeral area of the hind wings
(see p. 88) ; and in which radius of the hind wings is reduced
to an unbranched condition, while in the more generalized
forms the anal areaisnot reduced. The most available recog-
nition character is the dissimilarity in venation of the two
pairs of wings, due to the unbranched condition of radius of
the hind wings, while this vein in the fore wings separates
into several branches. (See Figs. 10-33, except Figs. 27, 28).

B. THE MICROFRENATA.

Moths of small, often minute, size. The mouth-parts are
usually functional. The anal area of the hind wings is not
reduced, having three anal veins except in certain minute
forms where a broad fringe has been substituted for the mem-
brane of this area.

This division of the order is the Microlepidoptera of authors
less the Micropterygide. But the statement made in many
books that the presence of three anal veins in the hind wings
distinguishes this group from the Macrolepidoptera is incor-
rect, for many of the Macros. possess this characteristic.

I believe, however, that the retention of the maximum
number of anal veins in the hind wings by the Microfrenatze
is an index of an essential character of the group ; while in
the Macrofrenatz, when it occurs, it is merely an indication of
a slight degree of divergence from a primitive type. In other
words, I believe that in the Microfrenatze the tendency of
natural selection is to develop that mode of flight which re-
quires broadly expanded hind wings. Whilein the Macro-
frenate the tendency has been at first in all groups and con-

Evolution and Taxonomy IOI

stantly in some to develop a mode of flight requiring narrow
wings.
This division of the order includes three superfamilies. I
have nothing to add to their well known characteristics.
Superfamily TINEINA.
Superfamily TORTRICINA.
Superfamily PyYRALIDINA.

BB. THE MACROFRENATA.

Moths usually of medium or large size; a few are small.
The anal area of the hind wings contains less than three anal
veins except in some generalized families where the maximum
number persists ; but in these families this character is usually
correlated with rudimentary or aborted mouth-parts (see p. 48);
and merely indicates a slight degree of divergence from a
primitive type.

To this division of the order belong the most generalized of
living Frenate; but this division also includes the most
specialized of all Lepidoptera. I therefore place it after the
Microfrenate in an ascending series.

c€. THE FRENULUM-CONSERVERS.

Under this head may be grouped those families of the Ma-
crofrenatze in which the two wings of each side are united by a
frenulum. They are the families in which the tendency of
natural selection is as a rule to conserve the frenulum, al-
though in certain genera this organ may be greatly reduced.

The first separation of this group into divisions is indicated
I believe by a difference in the order of reduction of the anal
areas of the two pairs of wings. In one division (D), repre-
sented by Casinia (Fig. 15), the reduction of the anal area of
the hind wings precedes the reduction of the anal area of the
forewings. In the other division (DD) the reverse is the case.
As we have no representatives of the first division in the North
American fauna, and asI have had but limited opportunity
to study exotic forms, I will discuss only the second division,
which includes those frenulum-conserving moths in which

102 John Henry Comstock

the reduction of the anal area of the fore wings precedes the
reduction of the anal area of the hind wings.

FE. The Generalized Frenulum-conservers. — Moths in
which the anal area of the hind wings retains three veins, and
in which the base of media of one or of both pairs of wings is
preserved. In all of these moths the second branch of media
(vein V,) tends to become united with cubitus, thus forming a
four-branched cubitus.

This is to acertain extent an artificial division, being based
on characters that represent merely a degree of divergence
from a primitive type. But it is really much more nearly a
natural division than would seem at first sight. For if we
omit those Zygzenids that are included in it, it consists of four
families, each of which is comparatively little removed from
the stem form of the Frenatze, and each represents a complete
line of development. It is a grouping together of several
short stems that arise near the base of the genealogical tree.
In the case of the Zygzeenids included here we have to do with
generalized members of a line of development which has
reached in its more specialized forms as great a degree of di-
vergence from the primitive type as has been attained by any
members of the order.

I place but little weight upon the divisions of this group of
families indicated below and in the table above. It is merely
a convenient distribution based on recognition characters, and
is not intended to represent affinities. For I believe each of
these families represents a distinct line of descent, between
which and any other line we at present know no connection
except that of the common progenitor of all Frenate.

F. Moths in which a great reduction of the subcostal cell of
the hind wings is taking place, the subcosta and radius being
grown together to near the end of the discal cell. (Figs. 10,
25.)

G. Moths in which the anal veins of the fore wings anas-
tomose so as to appear to be branched outwardly, (Fig.
25). ‘The extremely generalized condition of these moths is
shown by the slight reduction of the anal areas, there being
three anal veins in both fore and hind wings, although veins
IX and XI of the fore wings coalesce to a considerable

Evolution and Taxonomy 103

extent. The clothing of the wings is also in an extremely
generalized condition, (see p. 93), and the larvze too represent
a generalized condition, having ten pairs of feet, three thora-
cic and seven abdominal.

The coalescence of subcosta and radius of the hind wings
reminds us of what occurs in several of the more specialized
families. But these moths cannot be regarded as representing
the stem form of any of those families, as this coalescence takes
place here before there is any reduction of the anal areas, while
in the more specialized families referred to the anal areas are
reduced first. This group is represented by a single family.*
There are two North American genera Jegalopyge (Lagoa)
and Carama. Family MEGALOPYGID.

GG. Moths in which the anal veins of the fore wings do
not anastomose in such a way as to appear to be branched out-
wardly. Three American genera, Acoloithus (Fig. 26), Trz-
procris (Fig. 10), and Pyromorpha, fall under this head.
They will be discussed later, when the superfamily Zyg@nina
is reached.

FF. Moths in which the subcostal cell of the hind wings is
not greatly reduced.

G. Moths in which the anal veins of the fore wings anasto-
mose so as to appear to be branched outwardly (Fig. 22).
These are the Bag-worm Moths. ‘They too show a general-
ized condition of the wings in the presence of three anal veins
in both fore and hind wings ; although in certain forms it is
difficult to make out all of the anal veins in the fore wings, as
the base of vein VIII is often wanting. ‘The females have
lost their wings entirely. The peculiar type of venation of
the wings of these insects can not be regarded as representing
the precursor of any other known type. I therefore look upon
these insects as representing a distinct line of development.
The group is represented by a single family.

Family PsycHIpD/.

* This family has been monographed by C. Berge. See Farrago Le-
pidopterogica. Contribuciones al estudio de la Fauna Argentina y
paises limetropes. An. Soc. Arg. XIII. See also Zool. Jahresbericht,
1882, This monograph seems to have been overlooked by American
writers.

104 John Henry Comstock

GG. Moths in which the anal veins do not anastomose in
such a way as to appear to be branched outwardly. This
group includes two families, which so far as their wing-struc-
ture is concerned are more closely allied to each other than is
either of them to either of the preceding families. In each of
the two families included here there is frequently exhibited a
marked tendency towards the abortion of radius of the hind
wings.

H. Moths in which the branches of radius of the fore wings
tend to anastomose, forming an accessory cell or cells (Fig.
12). The larvee are wood borers. Family Cossip&.

HH. Moths in which the branches of radius of the fore
wings do not anastomose (Fig. 16,17). The larve are ‘‘slug-
caterpillars ’’ and feed on the leaves of plants.

Family LIMACODID.

EE. The Specialized Frenulum-conservers. — Moths in
which the anal area of the hind wings is reduced, having less
than three anal veins, and in which that part of media which
traverses the discal cell is usually wanting.

This division of the order is a very extensive one, including
the greater number of the moths; it is represented in our
fauna by thirteen groups, which are either of family or super-
family rank.

In several cases a family seems to be quite isolated ; while
in other cases several families can be brought together into a
single larger group. I recognize two such groups. But in
neither case does the group seem to be sufficiently homoge-
neous to be regarded as a superfamily ; it must be regarded in
each case as a provisional arrangement, which will be of use
until the affinities of the families are better understood.
These two groups are defined under FF and FFF below.
Under F and FFFF are grouped the isolated families.

F. The family Dioptide represented by the genus Phry-
ganidia, which occurs in California, seems to represent
a distinct line of development. For it presents a com-
bination of characters that sharply distinguishes it from
all other known members of our fauna. ‘The anal area of the
fore wing is reduced, vein IX alone being retained (Pl. III,

Evolution and Taxonomy 105

Fig. 6). In the hind wings veins IX and XI are well pre-
served and the distal part of vein VIII is represented by a
slight thickening of the membrane. ‘The second branch of
media in both wings nearly retains its primitive position ; in
fact it can not be said that a tendency to migrate in either di-
rection has been established, although the base of media is
lost. In the fore wings the third branch of media, and in the
hind wings both the first and third branches of this vein, have
become consolidated in each case with the adjacent vein to
a remarkable extent. Here is a high degree of specialization
in one direction correlated with a comparatively generalized
condition of certain other characters. Although subcosta
and radius of the hind wings are closely parallel, they are
distinct. The clothing of the wings is extremely general-
ized, consisting chiefly of narrow scales, with a single notch
at the extremity, and scattered irregularly over the surface
of the wing. The larve resemble those of some of the
Notodontidz. Family Diopripas.

FF. Zhe Geometro-Bombycids and the Geometrids.—Under
this head I group three families that have been quite widely
separated heretofore. This group includes those families of
the Specialized Frenulum-conservers in which the base of the
second branch of media (vein V,) tends to migrate towards
radius ; or in other words, those Specialized Frenulum-con-
servers in which the tendency is to form a three branched
cubitus. (See p. 76 for a discussion of the importance of this
character.)

G. Moths resembling Noctuids in their general appearance,
having heavy, strong wings; but readily distinguished from
that family by the direction of the migration of the base of
vein V,. In this family there seems to be but little if any
tendency to specialization of the humeral angle of the hind
wings. (Compare with the Geometridz below.)

Family NoTopONTIDé.

GG. Of this group I know only a single species, Brephos
infans. I therefore hesitate to characterize it. I believe, how-
ever, that this represents its natural position.

Family BREPHIDA.

106 John Henry Comstock

GGG. Moths in which the wings are usually delicate and
very finely scaled. ‘There seems to be a marked tendency in
this family to a specialization of the humeral angle of the hind
wings, and correlated with this a tendency towards the reduc-
tion of the frenulum, especially in the females of certain gen-
era. ‘This tendency, however, is a much later development
than the corresponding tendency with the Frenulum-losers.
A marked indication of the specialization of the humeral
angle of the hind wings which is exhibited by most genera of
this family is a bending forward into it of the basal part of
the subcosta and an elongation of the frenulum_brace.*
Both of these features are well shown by Auphenessa (Figs.
20, 21), which doubtless belongs to this group, although
it is commonly placed elsewhere. Family GEOMETRIDA.

FFF. Zhe Noctuo-Bombycids and the Noctuids.—The mem-
bers of this group can be recognized by a tendency of the base
of vein V, to migrate towards cubitus, and thus form a four-
branched cubitus, and an absence of the peculiar character-
istics distinctive of any of the families grouped under the next
division (FFFF).

G. Here belongs a small family, which, although apparent-
ly closely allied to the Noctuidz, exhibits striking peculiari-
ties of development. ‘There is no tendency towards a uniting
of the subcosta and radius of the hind wings (PI. III, 4), a
tendency shown in all other families of the Noctuo-Bombycid
division. ‘The migration of the base of vein V, is more marked
in the hind wings than in the fore wings, where it nearly or
quite preserves its primitive position. And the union of vein
V, of the hind wings with radius is by means of a compara-
tively long cross vein, so that veins III and V, appear to sep-
arate before the apex of the discal cell. In the males the tip
of the frenulum is knobbed. The genus Leftina commonly
placed in this family belongs to the Noctuide. ‘

Family CyMATOPHORID.

GG. The four families that follow I have not yet studied

* By the term /renulum brace I designate a sclerite situated on the
costal margin of the wing between the base of the frenulum and the
base of the wing.

Evolution and Taxonomy 107

sufficiently to warrant my expressing any views as to their re-

lationships to each other. In the Arctiide we find the most

marked tendency to the reduction of the subcostal cell of the

hind wings, subcosta and radius being consolidated in some
genera for the greater part of their length. (PI. III, 1).

Family NocruIipD&.

Family LIPARIDA.

Family AGARISTIDA.

Family ARCTIIDA.

FFFF. /solated families of specialized Frenulum-conservers.
—The families that are grouped together here agree with the
Noctuids and the Noctuo Bombycids in the direction of the
migration of vein V,, the tendency being to form a four-
branched cubitus. But each of the following families exhibit
striking peculiarities of specialization which isolate it from
all of the others as well as from the preceding group of
families.

G. The clear winged moths are placed here provisionally,
although I believe that their true position is among the Mi-
crofrenate. But as I have studied them and the Micro-
frenatee only superficially, I will not presume to make so
radical achange. In this family there is a high specializa-
tion of the wings, although the anal area of the hind wings
in many cases retains three anal veins. ‘This is a combina-
tion of characters not found elsewhere in the Macrofrenate,
but is quite characteristic of the Microfrenate.

Family SESIIDA:.

GG. The Window-winged Moths exhibit a type of wing
venation not seen elsewhere among moths. ‘The most strik-
ing feature of it is expressed by saying that all of the branches
of radius of the fore wings are preserved, and all arise from
the discal cell (Plate III, Fig. 2). A similar type of venation
is exhibited by the Hesperidze (Plate III, Fig. 1). Whether
this similarity has arisen independently, or whether it indi-
cates a closer genetic relationship than has been assigned to
these families heretofore I will not presume to say, with my
present knowledge. The fact that in the Hesperide the
frenulum brace is well preserved, may have some bearing on
the settlement of the question. Family THYRIDID&.

108 John Henry Comstock

GGG. The Hawk-moths can be recognized by the well
known form of their wings, and the presence of what has
been termed an intercostal vein (Fig. 24). If I am correct in
my interpretation of the homology of this vein, (see p. 78),
the family can be characterized as those specialized Frenulum-
conservers in which the base of costa of the hind wings is
preserved and is remote from the costal border of the wing,
and in which subcosta of the hind wings is consolidated
with radius for a distance and then separates from radius and
joins costa. This arrangement of the veins is quite different
from that which exists in Zygena, (Fig. 19), where also
costa of the hind wings is preserved. It more closely re-
sembles that of the silk worm, Sevicaria! (Fig. 32.)

Family SPHINGIDA.

GGGG. I place the Zygeenids last in this group of isolated
families because it is among them that we find the most
highly specialized representatives of the frenulum-conserving
Lepidoptera, (Cosmosoma, Syntomis, Fig. 11). On the other
hand certain genera, 77iprocris (Fig. 10) and Pyromorpha
present a remarkably generalized condition of wing structure.
The range of variation is greater than I have observed in any
other family or superfamily. In the more specialized forms
a greater degree of cephalization of the powers of flight has
taken place than occurs elsewhere in the order. And with
this cephalization there seems to be correlated a lengthening
of the fore wings and a narrowing of the basal part of the
area lying between radius and cwubitus of these wings. This
narrowing of this area appears even in our most generalized
forms, in which the discal cell of the fore wings can be well
described as petiolate. Another characteristic of the Zygee-
nina is the extent of the coalescence of the subcosta and
radius of the hind wings. A somewhat similar coalescence
occurs in certain genera of the Arctiide:; but it takes place
earlier (z. e., in more generalized forms) in the Zygeenina,
and is carried farther than in the Arctiidae. The Zygeenids
form a superfamily. The relationship of the families compos-
ing this superfamily have not been worked out. The Ameri-
can genera, so far as they are known to me, differ markedly from

Evolution and Taxonomy 10g

Zygena in the structure of the humeral area of the hind
wings. In none of them is costa preserved. The American
genera included here are Acoloithus, Triprocris, Pyromorpha,
FHlarrisina, Euchromia, Dahana, Didasys, Lycomorpha, An-
atolmis, and Cosmosoma. Of Euchromia I have studied only
exotic forms; Horama and Erruca are unknown to me, but
probably belong here also. ‘The position of the Ctenuchidze
I have not determined. Superfamily ZyGainrna.

CC. THE FRENULUM-LOSERS.

This division of the order includes those families of Lepi-
doptera in which the frenulum has been supplanted by a
greatly extended humeral area of the hind wings, (see p. 88).
In some of the more generalized forms a rudimentary frenu-
lum persists, (Sericaria, Perophora) ; in others it has been re-
tained by the male (Drepana). This division includes three
Sroups of families; the Frenulum-losing Moths, the Skippers
(Hesperidze), and the Butterflies.

D. The Lrenulum-losing Moths.

E. Moths in which cubitus is apparently three-branched.

Superfamily Sarurnira.*

*The following expresses my views regarding the affinities of the

members of this superfamily :

A. Moths in which the base of costa of the hind wings is preserved
remote from the costal border of the wing. This is shown by the
presence of an ‘‘intercostal vein” (Sericaria, Fig. 32.) (See p. 78.)
Frenulum preserved in a rudimentary state.

Family BomBycip#,

AA. Moths lacking an “intercostal vein.’”’ (These are the true Saturn-
ians. )

B. Generalized Saturnians, In these vein V, retains its primitive
position, midway between radius and cubitus ; and there are three
anal veins in the hind wings, the distal part of vein VIII being pre-
served (Fig. 31.) Frenulum preserved in a rudimentary state.

Family PEROPHORID&.

BB. More Specialized Saturnians. Vein V, of the hind wings appar-
ently a branch of radius (Fig 30); anal area of hind wings with not.
more than two veins, vein VIII having been lost; frenulum entire-
ly superseded by a greatly extended humeral area.

C. Antennz of both sexes with only a single pair of pectinations to
each segment. Family HEMILEUCIDa,

1 Ke) John Henry Comstock

EE. Moths in which cubitus is apparently four-branched.
F. Humeral angle not strengthened by humeral veins.
The frenulum is retained by the males in some genera. The
North American forms represent three genera: Dyepana,
Prionia, and Dryopteris. Family DREPANID&.
FF. Humeral angle strengthened by the development of
one or more humeral veins. There are eight North American
genera: Quadrina, Gloveria, Thauma, Clisitocampa, Hetero-
pacha, Artace, Tolype, Gastropacha. Family LASIOCAMPIDA.
DD. The Skippers.—These are day-flying Lepidoptera,
which resemble butterflies in usually holding their wings
erect when at rest. They can be recognized by the peculiar
venation of the fore wings, in which all of the branches of
radius are preserved, and all arise from the discal cell. Al-
though the frenulum is lost, the frenulum brace (see p. 106) is
well preserved in some genera. See discussion of the Thyri-
dide (p. 107) and compare the figures Plate II, Fig. 1, and PI.
TU ors Family HESPERIDA.

each segment, excepting the terminal segments in some.
D. Antennz of males pectinate for a little more than half their
length. Family CERATOCAMPIDA.
DD. Antenne of males pectinate throughout.
Family SATURNIIDA.

BOMBYCIDA).—The superficial resemblance between this family and
the next as shown by the single genus of each known to me (Sericaria
and FPerophora) is very striking. Buta study of the structure of the
wings shows marked differences (Figs. 31, 32). Note differences in the
method of coalescence of the branches of radius of the fore wings, in
the course of subcosta of the hind wings, and in the presence of an
‘intercostal vein.”

Sericaria appears to represent a line of descent quite distinct from the
true Saturnians as represented by the American forms. Do the ‘‘inter-
costal vein’ of Sevicaria and the caudal horn of its larva have any gen-
etic connection with the similar structures in the Sphingide? This
question suggests the desirability of a study of other Asiatic forms allied
to Servicaria. It should be remembered that although Sericaria and the
Sphingidee belong to widely separated divisions of the order, Sericaria
stands near the foot of one of them, being very generalized in structure.

PEROPHORID#.—I propose the establishment of this family to receive
the genus Perophora, the most generalized of the American Saturnians.

Evolution and Taxonomy 1G

DDD. The Butterflies.—If we remove the Hesperide from
this division of the order as indicated above, the butterflies
form a well defined group. It contains, however, two distinct
lines of descent which separated very early in the history of
the group. In one, after the abortion of the base of media,
vein V, migrated towards cubitus, forming a four-branched
cubitus ; in the other, this vein migrated in the opposite di-
rection. ‘There was also a difference in the order of the re-
duction of the anal areas of the two pairs of wings. See
page 44 for a discussion of the importance of this character.

E. Butterflies in which cubitus is apparently four-branched;
and in which the anal area of the hind wings is more reduced
than the anal area of the fore wings. In the fore wings all
three of the anal veins are at least partially preserved, while
in the hind wings there is only a single anal vein. PI. IT,
Fig. 2. Family PAPILIONIDA.

EE. Butterflies in which cubitus is apparently three-
branched ; and in which the anal area of the fore wings is

I aS an the figure ae deseion of eee that it Aldo belongs
here. /erophora has been classed in the Psychide merely because its
larva is a case-bearer. But it presents no affinities to the Psychide, be-
yond belonging to the same suborder, even in larval habits. The case
of the larva of Ferophora is of an entirely different type from that char-
acteristic of the Psychide.

HEMILEUCIDA.—This family represents a distinct line of develop-
ment within the Saturniina, which separated from the branch giving
rise to the Ceratocampidze and Saturniide before the origin of the pecu-
liar form of anteunz characteristic of these families. For although the
Hemileucide lack this peculiar specialization, the extent of the migra-
tion of vein V, that has taken place in this family, indicates a higher
degree of specialization in another direction than exists in any of the
Ceratocampide or in the lower genera (Coloradia and Hyperchiria) of
the Saturniidee. This family is represented in this country by two gen-
era, Hemileuca and Pseudohazis.

CERATOCAMPIDA.—I have nothing to add to the well known charac-
teristics of this family. There are five North American genera: Cithe-
ronia, Eacles, Sphingicampa, Anisota, and Dryocampa.

SATURNIIDA:.—We have eight genera representing this family ; these
are, beginning with the most generalized: Coloradia, flyperchiria,
Calosaturnia, Telia, Actias, Saturnia, Attacus, and Samia.

Ti2 John Henry Comstock

more reduced than the anal area of the hind wings, the former
having a single anal vein, the latter two, Pl. II, Fig. 3. This
group includes three families.

F. Butterflies exhibiting no tendency to abortion of the
fore legs. Family PIERIDA:.

FF. Butterflies exhibiting a marked tendency to abortion
of the fore legs.

G. Family LyCanIp&.

GG. Family NyMPHALIDA.

The most important innovation in the classification of butter-
flies proposed above, after the removal of the skippers, is the
dismemberment of the Family Papilionidee of authors, and
the raising of the Pierinze to family rank. I propose this
change unhesitatingly ; for it seems to me that nowhere
within the Frenatz is a dichotomous division of a line of de-
scent more clearly indicated than in this case.

If Iam right in my conclusions the much mooted question
as to which is the more highly specialized, the Papilionidze or
the Nymphalide, disappears. For we have to do, not with
two elements of a single series, but with the tips of two dis-
tinct lines of descent, each of which represents the highest
degree of specialization of its line.

It is difficult for one who has adopted the commonly ac-
cepted classification of the butterflies to realize the great
extent of the gap that separates the Papilionidze (as limited
here) from the other families of butterflies. The branching
off of the Papilionidz took place long before butterflies as-
sumed their present form. At the time when it occurred
there had been no reduction of the anal areas, and vein V, had
not begun its migration towards either radius or cubitus.
This is as generalized a condition of wing structure as exists
in any of the living Frenatee.

The division between the Pieridze on the one hand and the
Lyceenidze and Nymphalide on the other is also well marked.
If we compare the Pieridee with the Lyczenide, the more gen-
eralized of the last two families, we find that the Pieridze ex-
hibit a much greater specialization of wing structure (as
shown by the extent of the consolidation of vein V, with

Evolution and Taxonomy 113

radius) than do the Lycenide; but the Pieridz do not
exhibit that specialization by reduction of the fore legs which
is characteristic of the Lyceenidee and Nymphalide. In the
Nymphalide we find not merely the extreme of the reduction
of the fore legs, but an even greater specialization of the
wings than exists in the Pieridz.

ITHACA, N. Y.,
27 July 1893.

EXPLANATION OF PLATES.

PASE eile
(Engraved from nature by Anna Botsford Comstock.)

Fig. 1.—Smerinthus geminatus.
Fig. 2.—Hepialis argenteomaculatus.
Fig. 3.—Attacus promethea.

In Figure 2 is represented one of the most generalized of living Lep-
idoptera ; in Figure 1 is shown a form in which the wings are narrow,
being fitted for rapid flight ; and in Figure 3, one in which the wings
are broad, being fitted for a different mode of flight.

PLATE II.
(Drawn by E. P. Felt.*)

Fig. 1.—Audamus tityrus.
Fig. 2.—FPapilio polyxenes.
Fig. 3.—Pieris protodice.

AEs D, JOC
(Drawn by E. P. Felt.)

Fig. 1.—Halisidota tessellata.
Fig. 2.—7hyris maculata.

Fig. 3.—llatephemera antiqua.
Fig. 4.—Thyatira scripta.

Fig. 5.—Hexagenia bilineata.
Fig. 6.—Phryganidia californica.

* The figures in the text in the preceding pages were also drawn by Mr. Felt.

COMSTOCK. PIL ANGE, Wc

COMSTOCK. PCAN ING, WU,

THE VITAL EQUATION OF THE COLORED RACE
AND ITS FUTURE IN THE UNITED STATES.

By EUGENE ROLLIN CORSON, B.S., M.D.

In June, 1887, I delivered a lecture before the Georgia His-
torical Society, entitled ‘‘ The Future of the Colored Race in
the United States from an Ethnic and Medical Standpoint.’’
My object at the time was to refute certain writers who looked
upon the colored race as a menace to our country, and whose
sensational writings, prompted largely by political motives,
were calculated to cause wrong impressions and unnecessary
alarm. I attempted to show that a solution of the problem
could be found outside the figures from the census, namely,
in a study of the physical status of the race, their morbid ten-
dencies, and their mortality compared with that of the whites.

As a practicing physician in a typical southern city, in a
community where the colored almost equalled the whites, I
felt I was in a position to study the subject. Only they who
are brought into immediate contact with a race can form any
adequate ideas of that race in all its bearings. ‘They must see
how they live and they must see how they die before they are
qualified to judge of the race in its entirety, or atttempt to
answer such a vital question as its future.

It is a significant fact that they who live in the South and
who are brought into immediate relationship with the colored
people are the last ones to look with fear on the future. They
see but too plainly the many factors working against the race,
inimical factors which come from within the race and not
from outside. As the rise of a nation depends upon its own
inherent powers, so its fall can be traced to causes within its
ranks. Its enemies at home are more to be feared than its
enemies abroad.

Since 1887, when I wrote my paper above mentioned, we
have had another census. ‘his last census, I am glad to say,

116 Eugene Rollin Corson

has fulfilled almost in every way the predictions then made,
and I trust that with a fuller treatment of the higher mortal-
ity among the colored as compared with the whites, and the
causes which have produced it, we can see with greater dis-
tinctness the future of the race.

In this present paper then I shall go over largely the
ground treated in my first paper. I shall introduce the re-
sults of our last census, so far as the mere enumeration goes,
—for the volumes on mortality and vital statistics are not
yet out,—and finally elaborate certain pathological lines
which were then but faintly drawn. ‘This, I hope, in con-
junction with the mortuary tables of our own city, will give
us a fairly clear idea of the vital equation of the race, and by
vital equation I mean that quantum and power of vitality
which maintains individual life, for it is upon individuation,
I believe, that racial strength and progress depend. And
with high individuation goes a comparatively low death rate,
especially in infancy and early childhood, and a high general
average of age. Though the birth rate may be comparatively
low, more infants born become mature and perfected individ-
uals; there is more vitality for growth and development ;
racial traits and characteristics are stronger, with more
power to hold the race together asarace. There is no better
evidence of the great vitality of the Jewish race, for example,
than their power to preserve their racial traits all over the
world, and in spite of the many years of persecution and sep-
aration which they have had to endure.

After the tenth census of 1880, attempts were made to pre-
dict the future of the colored race from a few figures and the
multiplication table. Gaps were filled in to suit each indi-
vidual case and figures marshalled to suit the thesis. It was
surprising how some allowed themselves to be run away with
by these figures.

Professor E. W. Gilliam contributed an article to the Popw-
lar Science Monthly for Feb. 1883, entitled ‘‘ The African in
the United States’ in which he drew for us a lurid picture of
the future of our country. Here are his figures :

The Colored Race rE

Whites in United States in 1880 (in round numbers), . 42,000,000
Whites in United States in 1985 (in round numbers), . 336,000,000
Northern Whites in 1880,
Northern Whites in 1985,
Southern Whites in 1880,

Sees teethleen Ichiver ere Chern tran ne 30,000,000
BPN MBPS boc Mat ylS Niel: Medien Vahiirelt ss 240,000,000

EN meee tie a Lene Wal VieNe suc eh Bh es 12,000,000
Southern; Whites mMMIOSSs Myce AA Ge el ve cay aan vere rayite 96,000,000
Blacks in Southern Statesin 1880, ........4.4.. 6,000,000

Blacksiin Southern States in) T9o80) 29520505. 3 192,000,000

This is figuring with a vengeance. We may well tremble
for the future of our country if these figures are even approx-
imately correct. Their menace, Professor Gilliam thinks, is
intensified by the second factor in his arguments, namely the
impossibility of fusion of whites and blacks.

Mr. Albion W. Turgée attempted to reach the same con-
clusions in a book entitled ‘‘An Appeal to Ceesar.’’ His
book is a strange medley of figures, hypotheses, and circus-
bill English. It is wholly unnecessary for us to quote from
these writers or give any resumé of their arguments. It will
not be amiss, however, to quote at some length from Mr.
Henry Gannett’s refutation which appeared in an article in
the Poputar Science Monthly for June 1885, entitled ‘‘ Are we
to become Africanized?’’ He gives here their arguments and
refutes them by their own figures. In refutation of Professor
Gilliam he writes :—

‘An analysis of the author’s curious method of deducing
these results will, however, dispel this frightful vision of the
future. ‘The increase of white population between 1870 and
1880 was slightly less than ten millions. The number of
immigrants during this period was a little in excess of two
million eight hundred thousand. Subtracting the latter from
the former, there is left a number which is 23 per cent. of the
population in 1870, not 20 per cent., as Prof. Gilliam has it.
But what does this 20 or 23 per cent. (it matters not which)
represent? Certainly not the increase of native whites, as he
interprets it. The census gives directly the numbers of native
whites in 1870 and in 1880, and the proportional gain of this
class during the decade was not less than 31 per cent. These
are the figures he should have used in making his calculations.

118 Eugene Rollin Corson

‘‘ Now as to the increase of the colored element. Professor
Gilliam at the outset, deducts from its rate of increase 5 per
cent., representing about a quarter of a million persons, on ac-
count of the imperfections of the census of 1870. Concerning
the omissions of this census little is known, except that they
were generally distributed through the cotton States, were
largely, if not mainly, of the colored element, and of that
element, approximated nearer three-fourths of a million than
one-fourth, and certainly exceeded halfa million. Professor
Gilliam’s subsequent addition of 5 percent. ‘as an obvious con-
sideration points to the conclusion that the blacks will for the
future develop in the South under conditions more and more
favorable,’ certainly is not warranted by the facts or the proba-
bilities, and, as we are reasoning from what has been and is,
and not from what may be, it looks very much like begging
the whole question.

‘Correcting Professor Gilliam’s statements, it appears that
the ratios of gain during the past decade were, as nearly as
can be known, as follows: For native whites, 31 per cent. ;
for blacks, not above 25 per cent.

‘‘ But all such comparisons, based upon the results of the
ninth census, are utterly worthless. No reliable conclusions
regarding the increase of negroes can be drawn from a com-
parison in which these statistics enter. The extent of the
omissions can be a matter, within certain wide limits, of con-
jecture only. ‘The only comparisons which yield results of
any value are those made between the statistics of the eighth
and tenth censuses. ‘That the former was, to a certain slight
extent, incomplete, is doubtless true, especially in regard to
the colored element, but the omissions were trifling as com-
pared with those of the ninth census. A comparison between
the results of the eighth and tenth censuses shows the ad-
vantage to be clearly in favor of the native whites, who in-
creased 61 per cent. in the twenty years, while the colored
element increased but 48 per cent. ‘This great increase of the
native whites was effected in spite of the fact that the ranks of
the adult males were depleted to the extent of over a million
by the casualties of war, which the negroes scarcely felt.”

The Colored Race 11g

In reply to Mr. Tourgée he writes :—

‘‘In ‘An Appeal to Cesar,’ by Judge Tourgée, the ques-
tion of the future of the colored element is discussed from a
somewhat different point of view. Without committing him-
self as to the increase or decrease of the colored element in
the country at large, in proportion to the whites, the author
finds, upon a somewhat superficial study of the statistics bear-
ing upon the question, that in the South Atlantic and Gulf
States the negroes have increased decidedly in proportion to
the whites, while in those States which he classes as Border
States they have relatively decreased. This massing of the
negroes in what may, for convenience, be denominated the
cotton States, coupled with the steady sharpening of the line
of separation between the two races—a line which, as the
author claims, becomes more and more accentuated as the in-
ferior race increases in numbers and advances in education—
will lead to inevitable conflict between the two races. As the
negro becomes numerically the stronger, and, through educa-
tion, appreciates more fully his present position, he will com-
mence astruggle for the mastery, and then the days of the Ku
Klux will be eclipsed in blood and slaughter. Such is the
condition to which these ill-fated States are hurrying. To
ward off this impending evil Judge Tourgée urges upon the
general government the work of educating the blacks. Such,
in brief is the ‘ Appeal to Cesar.’ a * * us
a * xx * * * * *

‘‘Tt may, in passing, be suggested that a careful revision
of his figures will show many important arithmetical errors,
which may modify very sensibly some of his conclusions. It
is unnecessary to follow his methods of reasoning, as the truth
regarding the questions at issue can be arrived at much more
directly. The fact is, that the negro is not migrating south-
ward. There is no massing of the colored people in the cotton
States. In 1860 the colored element of these States formed 66
per cent. of the colored element of the country. In 1880 it
formed precisely the same proportion. Between 1860 and 1880
the colored element of the country increased 48 percent. The
same element of the cotton States increased, in this interval,

120 Eugene Rollin Corson

in precisely the same proportion, neither more nor less. These
figures are conclusive upon this point, and from them there is
no appeal.

‘‘But the fact remains that, in these cotton States, the
colored element was in 1880, in comparison with the white
element, slightly stronger than it was twenty years before.
This, however, is due not toa southward movement of the
colored people, but to a decrease in the rate of increase of the
whites of those States. While the increase of the native white
population in the country at large between 1860 and 1880 was
61 per cent., that part of the same element resident in the
cotton States increased but 39 per cent. This low rate of in-
crease among the whites might seem to establish Judge
Tourgée’s position, though not in the way he states it, were
it not for the fact that three-fourths of this increase took place
during the decade between 1870 and 1880. ‘The increase of
whites in the South received a most effectual check during the
four years of war, in which every male capable of bearing
arms was in the field, and in which fully half a million laid
down their lives. Since the war the white race has taken up
arate of increase equal to, if not greater than, that of the
country at large, a greater rate than that of the colored people
within its borders, and there is no apparent reason why they
should not maintain it. It is not, then, a migration of the
negroes southward which has caused their relative gain in
these States, but it is the losses of the white race—losses
which, however, are rapidly being repaired.’’

It will be interesting now to look to the deductions of the
Eleventh Census, and see to what extent it agrees and where
it differs from this succinct resumé of Mr. Gannett. I have
before me Census Bulletin No. 48, giving the white and the
colored population of the South for 1890. As that section of
our country denominated the South Atlantic and South Cen-
tral States with Missouri and Kansas, contained fifteen-six-
teenths of the entire colored population of the United States,
a race count of these states was made in advance of the main
work of tabulation. The total population in this count was
found to be 23,875,259, of which 16,868,205 were whites,

The Colored Race 121

6,996,166 were colored, and 10,888 were Chinese, Japanese,
and Indians.

The Bulletin goes on to state: ‘‘’The abnormal increase of
the colored population in what is known as the black belt |
during the decade ending in 1880 led to the popular belief
that the negroes were increasing at a much greater rate than
the white population. This error was a natural one, and
arose from the difficulty of ascertaining how much of the in-
crease shown by the Tenth Census was real and how much
was due to the omissions of the Census of 1870. This ques-
tion has been fully discussed in Bulletin No. 16, and it is now
merely necessary to add that the tabulations herewith given
sustain the theory already advanced, that the high rate of
increase in the growth of the colored population as shown in
1880 was apparent, not real, and was due to imperfect enu-
meration in the Southern States in 1870.

‘* Attention is first called to Table I, on the following page,
showing the white and the colored population of the states under
discussion at each census since 1790, together with the num-
ber of colored to each one-hundred thousand white and the
percentage of increase respectively, of white and colored for
the several decades.

‘“The table summarizes the entire case. In 1890 there were
in the States under discussion 6,996,166 colored inhabitants,
and in 1880, 6,142,360. ‘The colored element increased dur-
ing the decade at the rate of 13.90 per cent. ‘The white pop-
ulation of these states in 1890 numbered 16,868,205, and in
1880, 13,530,408. They increased during the decade at the
rate of 24.67 per cent. or nearly twice as rapidly as the colored
element.

‘‘In 1880 the proportion of white to persons of color in
these states was in the relation of 100,000 to 45,397. In 1890
the proportion of the latter class had diminished, being then
as 100,000 to 41,475.

122 Eugene Rollin Corson

POPULATION. No. of Colored) Per Ct. of Increase.

YEARS. = bas to Tey, Pie

White. | Colored. 100,000 White.| White. | Colored.
LZOOe |) L271. 485 689, 884 | 54,258 rahe 2 We
TSO.) /))|//" 1,702.980 918,336 53,925 33-94 33.11
1810. .| 2,208,785] 1,272,119 57,594 29.70 38.52
1820. .| 2,831,560) 1,653,240 58,386 28.20 29.96
1830. .| 3,660,758} 2,187,545) 59,757 29.28 32-32
1840. .| 4,632,530] 2,701,901 58,325 26.55 23.51
1850. .| 6,222,418] 3,442,238 55,320 34.32 27.40
T5G0)- {|| 8,203,852! 4, 206,24 n 51,393 31.84 22.49
1870. .| 9,812,732] 4,555,990 46,429 19.61 8.06
1880. . | 13,530,408} 6,142,360 45,397 37.89 34.82 |
1890. . | 16,868,205) 6,996, 166| 41,475 24.67 13.90

‘‘ During the past decade the colored race has not held its
own against the white in a region where the climate and con-
ditions are, of all those which the country affords, the best
suited to its development.

‘‘Referring again to this table, it is seen that in but three
decades, that is, from 1800 to 1830, during a part of which
time the slave trade was in progress, has the colored race in-
creased more rapidly than the white. Since 1830 the white
people have steadily increased at a more rapid rate than the
colored. ‘This increase has not been effected by the aid of
immigration, for with the exception of Kansas and Missouri,
these states have received comparatively few immigrants
either from foreign Countries or from the Northern States.

‘* Similarly the proportion of the colored inhabitants to the
white increased somewhat between 1800 and 1830, but since
that time it has steadily diminished. In 1830, when this
proporticn was at its maximum, there were nearly 6 colored
inhabitants to 10 whites, but this proportion has been reduced
to a trifle more than 4 at the present date, or by nearly one-
third of its amount.’’

And again on page 5:

‘The last two tables are of special interest as they illustrate
the movements of the colored element during the past half
century. An inspection of them makes it evident that there
has been no extended northward movememt of this element
since the time of the civil war. Indeed with the exception of

The Colored Race 123

the District of Columbia, the border states appear to have lost
rather than gained, and during the last decade there becomes
perceptible a southward movement of the colored element from
the border states into those bordering the Gulf, particularly
into Mississippi and Arkansas, where they have increased
proportionately to the whites. Let the states under consider-
ation be divided into two groups, the first comprising Dela-
ware, Maryland, District of Columbia, Virginia, West Vir-
ginia, North Carolina, Kentucky, Tennessee, Missouri, and
Kansas, and the second, South Carolina, Georgia, Florida,
Alabama, Mississippi, Louisiana, Texas, and Arkansas. In
the first of these groups the increase of the white population
from 1880 to 1890 was at the rate of 22 per cent., while that
of the colored element was but 5.50 percent. In the second
group the rate of increase of the white was 29.63 per cent.,
while that of the colored race was but 19.10 per cent. In
the first group the number of colored to 100,000 white dimin-
ished from 80,116 to 73,608, or only 8.12 percent. There is,
therefore, a perceptible tendency southward of the colored
people, which, while by no means powerful, has resulted in
drawing a notable proportion of that element from the border
states, and in producing in two of the far Southern states a
more rapid increase of the colored element than of the white.

‘“Of the states under discussion, three, namely, South
Carolina, Mississippi, and Louisiana, contained in 1890 a
larger number of colored people than of white. Of the pop-
ulation of South Carolina more than three-fifths are colored.
Five other states, namely, Alabama, Florida, Georgia, North
Carolina, and Virginia, contained a colored element ranging
from one-third to one-half of the population.’’

So much for the Census. This southward movement of the
colored from the border states into the gulf states, is what we
might naturally expect. ‘The climate and soil are more con-
genial to the race, but more especially does it show an avoid-
ance of contact and competition with the denser white popu-
lation of the Northern, Middle, and Western States. "The
crowds of poor and alien whites which flock to us from
Europe, throw themselves into the main streams of popula-

124 Eugene Rollin Corson

tion fearlessly, and we may say successfully, for with surpris-
ing rapidity they become an integral part of our white popu-
lation. ‘Though many fall by the wayside, many fight their
way tothe front. The struggle is not so great for them as in
the older country. Of the same great race, brain and spine
are equally pitted, and they run the same chances with the
multitude. This southward migration then of the colored is
a most significant fact.

Though I, of course, put a high value upon the census
enumeration, I have always regarded the question of relative
mortality as the pith of the whole matter. In the census enu-
meration there are many sources of error, and they have been
most evident in several of the censuses. On the contrary, in
a study of the relative mortality of the two races living to-
gether under similar conditions of soil and climate, the mor-
bific tendencies whieh produce these racial differences come
directly before the observing physician, and they soon be-
come so evident that he who runs may read. I feel quite
sure that there is not a competent physician practicing in the
south among the two races who will not assure you promptly,
that the colored race has not the vitality of the white race,
and he will immediately show you in how many ways this
has been brought home to him. A southern city, then, with
a large population of white and colored, becomes a great
‘““culture’’ ground where the many factors in the struggle for
individual and racial life can be scientifically studied. I
therefore purpose to show more plainly the sources of this
greater mortality among the colored, and draw more sharply
the perspective lines which lead to but one goal, the decadence
of the negro as arace. ‘To this end I have studied carefully
the mortuary records of my own city, and I shall show that
they tally fairly well with the mortality tables of the Tenth
Census, prepared under the supervision of Dr. John S.
Billings, in volumes XI and XII. ‘The corresponding vol-
umes to come of the Eleventh Census will show even more
clearly, I believe, these great racial differences.

Reviewing the general mortality one is struck with the ex-
cessive mortality under the first year of life which in a meas-

The Colored Race 125

ure is sustained up to the fifth year, when the vital forces
having escaped Scylla at least, have gained sufficient head-
way to give the individual hope of passing Charybdis and of
reaching the alloted term of life. ‘Then reviewing the speci-
fied causes of death, we find consumption heads the list,
followed by diseases of the nervous system, pneumonia, acci-
dents and injuries, diarrhoeal diseases, diseases of digestive
system, malarial fever, measles, other diseases of respiratory
system, diseases of circulatory system, diphtheria, affections
of pregnancy, enteric fever,scrofula and tabes, venereal diseases,
cancer and tumors, scarlet fever, diseases of urinary system,
bronchitis, and diseases of the female generative organs.

The following table giving the age summary for the last
nine years is of interest as showing the high mortality during
the first year of life where the colored mortality more than
doubles that of the whites. These figures must be viewedina
population of about 25,000 whites and 20,000 colored, orin that
proportion. The mortality rapidly falls then for both races,
reaching its lowest point between 5 and Io years, the colored,
however, more than doubling the whites. The mortality
rises again for both races, reaching its highest point in the
decade between 30 and 40, when it falls off again, and in the
decade between 50 and 60 the mortality is about the same for
both races. There is but little change in the decade between
60 and 70. Between 70 and 80 the colored mortality is greater
again, becoming greater still between 80 and go, and still
greater between 90 and 100. This might lead one to think
that the colored reach a greater age than the whites. But it
must be remembered that the negro’s age is usually much
over estimated, that few know their right age and they are
inclined to add any number of years, so proud do they feel of
their senility. And, further, many of these negroes now rap-
idly passing away, are survivors of the old régime, when they
were well cared for, aud had reached at emancipation a safe
age which kept them out of the struggle of life. They are
relicts of better days for them, pure blooded negroes almost
entirely, who passed their first fifty years in slavery, and un-
der much better conditions for their physical well being than
the new generation can boast of.

Eugene Rollin Corson

126

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neither do they extend

It is the mortality of the early years of life

These figures are not large enough,
over a sufficient number of years, to draw entirely conclusive

generalizations from, still they are suggestive, and show at least
the high infant mortality which has such an important bearing

on our subject.

The Colored Race 127

which decides virtually the general mortality, and on the
contrary, the reduction of this infant mortality points to a
higher vital equation. I give here a table showing the rela-
tion of the mortality up to the fifth year to the total mortality
for the colored for the last nine vears.

| YEAR. 1884 1885 1886 1887 1888 1889 1890 1897 1892|Total. |

|
| rete
| u ! |

| | | | |

APR AMEUe PMT aGlepatal OK (ja [Oral CRIS Tali al Re Ta a Tein |

| Total mortality, . . | 703) 659) 936 796 665 685| 870 746, 834 6894 |

| Mortality up to 5th) | | |

| VWearer aan 278] 262) 431 324| 282) 278] 372| 260) 338} 2825 |
| |

These figures show that about 41 deaths out of 100 occur
before the fifth year.* Here is a similar table showing the

white mortality :

YEAR. 1887 1885188 1887 1888 1889 1890 1897 1892 Total.
| | |

} }

Total mortality, . . | 466 333, 452) 460] 366] 384 479 464) 468} 3872 |

Mortality up to 5th) |
VEAL, Myst fesse 40: 156) 109) 173} 150] 97| 128) 145] 135| 131 1218 |

| |
|

* To quote to any extent from the Tenth Census in the relation of
age to deaths would swell this paper beyond its proper limits. If the
reader can refer to Section IV, p. xxiv, Vol. XI of this Census, he
will find some interesting tables, not only comparing the cities with
the rural districts, our own states with the countries of Europe, but also
the two races in those parts of our country where the colored exist in
any number. The two tables on p. xxxii give the proportion of deaths
for each age or groups of ages for white and colored, and show the
much greater mortality of the colored under one year, and under the
fifth year.

“In the southern groups, among the colored population, over half
the deaths of males reported, or 507.16 per 1000, under 5 years of age,
and for colored females, 438.47 deaths out of every 1000 reported are
under 5 years.’’ The greatest mortality among infants under one
month occurs in Charleston, where the deaths for white males are
571.4, and for the white females 647.7 of each 1000 deaths under one
year.

128 Eugene Rollin Corson

This shows for the whites during the last nine years that a
little over 31 deaths out of 100 occur before the 5th year of
life, almost 10 per cent. less than the colored. Of course it
must constantly be borne in mind that these figures are for
the city, and that the mortality in the country is much less
for both races. But it is only from the cities that we get any
accurate returns, and more important still, that this is the
very point at issue, namely, the mortality of the two races
when brought into direct contact and sharp competition.
And it is this large source of error in the returns from the
country which vitiates the general returns given in the
census, and especially so in the returns of deaths among the
country colored. Like a bird’s-eye view, it shows a large
area but no distinct outlines or details.

We have had recently some interesting figures from Japan
bearing upon this question. It seems that Japan isa paradise
for children ; they are well cared for, and the greatest atten-
tion is given to their food. In 1872 the population was 33, 110,=
000 and in 1890 it had risen to 40,070,000. Mr. Ourakami
attributes this great increase to the low death rate among in-
fants. ‘‘It appears that next to France Japan has the lowest
birth-rate of any known country, but this is counterbalanced
by the conservation of infant life. In fact, in point of infant
mortality, Japan at present stands next to England among the
nations of the world. Thus while in Russia the death-rate
per 1,000 among children under 5 years of age is 423, in
Bavaria 405, in Austria 390, in France 341, in Prussia 335, in
Japan it is 276, and in England 255.’’*

Without having any proper birth-returns to show the mor-
tality per 1,000 among colored infants, the figures in the
above tables, if joined to the large number of still-births
and premature births, show an exceptionally high mortality,
higher than any figures given above. On this point I have
no doubt. This is without question the pivotal point in the
matter, and I shall go into some details to bring into re-
lief its main features. I shall indicate the causes of ante-natal

* The Medical Record, March 18, 1893. p. 352.

The Colored Race 129

mortality, of the death of the child at birth and during the
lying-in-period, and finally of the dangers besetting it during
its first years of life.

Despite the prolificness of the negress, the child zz utero has
many chances against its coming toterm. The temptations
aud irregularities of illegitimacy swell the list of premature
and still-births, and the number reported is but a poor show-
ing of the real number of cases. They are looked to by
‘“grannies’’ and ignorant midwives. The foetus before the
viable age is gotten rid of and finds no record at the Health
Office, while the viable child usually dies from neglect and
carelessness, if not from criminal measures. The mother
practically receives no treatment, and she is soon up and about,
with her uterus and adnexa in a diseased state.

Although I have no figures to bear me out, I am persuaded
that the prolificness is lowered, and that the lability to mis-
carriage is increased, by miscegenation. This has certainly
been my experience, and is in accord with the generally low-
ered vitality resulting therefrom.

It is of course well known that the poisons of syphilis and
gonorrhcea both favor a throwing off of the product of concep-
tion. In the colored this is seen with redoubled force, due to
the fact that both these diseases are apt to be virulent with
them, and also that they do not realise their dangers or take
the trouble to be properly treated. Again the very early age
at which they become infected adds to the dangers from this
source. The high types of fever, vaguely styled bilious, gas-
tric, malarial remittent, and conjestive, to which the colored
are by their occupation more exposed, and to which they have
become more and more susceptible, frequently result in mis-
carriages. I haveseenit follow tuberculosis pulmonum, gen-
eral tuberculosis, pneumonia, and measles, to all of which
diseases the colored are liable, and which prove very fatal to
them. The usual causes which operate with the whites oper-
ate with them, and, as all the returns show, with even greater
effect. The following table I have made up from the mort-
uary reports of the last nine years :

130 Eugene Rollin Corson

YEAR. 1884 1885 £886 1887 1888 1889 1890|1891\1892\ Total.

% : W 25 20 ial! 24 33 25 (34) Agi 2m aes.
Still-births, . . eS 78 | 133] 144] IOI] 97 | 122] 116) 116] 133] Io4o

W 14 LO}! 7) N20 TOU |) 2Ol 2) ] 24 Nia eer
Premature do ee | 41 5, 161 33 | 34] 25| 191 20] 177

It will be seen here that the still-births are more than three
times as numerous among the colored as among the whites,
but that there is virtually no difference in the returns of pre-
mature births. It must be remembered that with premature
births they can more easily evade the law, and that they will
avoid reporting their cases whenever they can. It is only ne-
cessity which compels many to get a burial permit. Nat-
urally, therefore, these figures must be far from the truth.

According to the Tenth Census, vol. XII, p. LXAXV,
‘The proportion of deaths reported as due to infanticide is
highest among the colored population, being 14 out of each
100,000 deaths from specified causes, while for the whites in
the same regions it is 5, and in the large cities 3, and in the
rural districts 5 per 100,000.’’ ‘The poor returns from the
rural districts account for the last figure which, of course, is
incorrect. And again: ‘‘ It will beseen from table 75 that the
proportion of infants reported as still-born is much greater in
the cities than in the country, decidedly greater among those
of German than among those of Irish parentage, and some-
what greater among the colored race than among the whites.
A certain number of cases reported as still-born are really
cases of infanticide.’’

From the nature of the case the returns must be especially
imperfect; the mortality from child-birth naturally calls
for mention here. By far the largest portion of the colored
employ midwives, only calling in a physician when there is
dystocia, and even then they wait till the eleventh hour, en-
dangering the life of both mother and child. These mid-
wives are usually dirty, ignorant, and meddlesome, often
changing a natural presentation into an unnatural one, im-

The Colored Race 131

perilling both mother and child. It is not uncommon to find
a midwife vigorously rubbing the abdomen of the poor
puerpera, in view of helping the pains, and producing a more
or less complete version of the child. The woman is delivered
in a small room, all air and light shut out, and the atmosphere
reeking with the emanations of the anility of the neighbor-
hood, who have come in to view an event which has always
the charm of a novelty. To these cases the physician is fre-
quently called to meet all possible forms of dystocia, danger-.
ous to both mother and child. Puerperal convulsions are
more common among them than among the whites, and the
mortuary tables show twice the mortality among the colored.
I have myself attended twenty-two cases of this disease, 8
whites and 14 colored, with two deaths among the whites and
six deaths among the colored. Of the children, four died
among the white and nine among thecolored. In many cases
I was only called in after much precious time had been lost.
My case book will show all possible presentations and compli-
cations. I may mention placenta preevia, ruptured uterus,
large uterine fibroids to which the negress is especially, liable,
puerperal septicaemia and peritonitis, neglected retained pla-
centa and all its dangers. And I may mention lacerations of
the cervix and perineum, and vesico-vaginal fistula. I men-
tion these because there is a common belief among those who
do not know, that the negress is like her African sister, who,
living in a savage state, is free from these complications of the
modern civilized woman. She is not only liable to them, but
from neglect and improper treatment suffers more than. the
white. This must affect her prolificness with even greater
force in the future. In going over the reports in the last nine
years, I find the figures too meagre and the diagnoses often
vague, so that it has but little value to us, except as showing
that the mortality among the colored exceeds that of the
whites, about in the proportion of 2 to 3.

* See my paper in the Wedical Record for Oct. 24, 1891.

132 Eugene Rollin Corson

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Referring to the Tenth Census I find the following state-

ment in regard to deaths from child-birth: ‘‘The following /

table shows by grand groups the proportion of deaths from
child-birth and from abortion per rooo deaths from known
causes, with distinction of rural and cities, and for certain

The Colored Race 133

grand groups, for white and colored, and of Irish and Ger-
man parentage. It will be seen from this table that the mor-
tality in child-birth is about twice as great in relation to the
deaths from known causes in the colored female as it is in the
white, and that it is markedly greater in those of German
than itis in those of Irish parentage. The same rule holds good
as regards abortion although the difference is less marked. A
large proportion of deaths due to criminal abortion are report-
ed as deaths from peritonitis, which is the cause in part of the
excess of deaths in females reported as due to that disease.*”’

The colored infant comes into the world under very ad-
verse circumstances, and the many dangers besetting it be-
fore its fifth year make one wonder it ever reaches maturity.

One ofits first dangers is trismus nascentium. ‘The following

YEAR. 1884 1885|\1886 (7887 1888 | 7889 1890|1897\1892\Total.

oN CRU See BARGE bet

Trismus Nascentium

C2840. 36 | 34 270) TAs TF tae | 220) a3

figures make the colored mortality from this disease more than
six times that of the white. Modern research has shown

the cause of tetanus to be a bacillus common in garden mould.
Here is a case of marked racial susceptibility. The filthy
way in which the infant is dressed renders it still more liable.
I have never seen a case recover ; and here in our city alone
232 colored infants have died from this disease in the last nine
years !

I give here for comparison the cases of tetanus in the adult
for white and colored for the last nine years.

YEAR, 1884 | 1885 188611887 1888|1889|r890| 891 1892 Total.

ahi 2 2. |e eee 2 fe) A} 2 17

Tetanus

NO

| ay 0 (ing PW TRS REP 3 | 26

'
= s : == 1

*Vol. XII, p. lxxi.

134 Eugene Rollin Corson

Though the colored mortality exceeds that of the whites, the
disparity is much less than in the case of trismus nascentium.

According to the Tenth Census the proportion of deaths
from tetanus and trismus nascentium are for the whites 33.5
and for the colored 29.3 per 1coo deaths from known causes.
I cannot think that these figures are reliable. The much
greater susceptibility of the negro is generally recognized.

Gastro-intestinal diseases, with their accompanying disor-
dered digestion and malnutrition, carry off the largest pro-
portion of white infants and young children. With all
nations it is among the poor and overcrowded that we see the
highest mortality, where ignorance and poverty swell so
greatly the death list. These factors, of course, exist among
the colored to a large extent, though I do not think they ever
have to endure anything like the lethal influences of the tene-
ment life of our great cities. Living in warmer climates they
escape the sufferings of intense cold poorly provided for, and
their homes which consist of one-story frame houses or huts,
are infinitely better, with all the dirt, than the small rooms
and high stories of the city tenements. Ifthe colored had to
live under such conditions the infant mortality would greatly
exceed that of the tenement poor of the great cities as well as

their own present death rate. Fresh air and proper, clean ©

food, would probably reduce this death rate one half. This
important factor of proper food never enters the head of the
ordinary colored mother. Even when liberally provided
with nature’s food, the breast is soon discarded for dirty
feeding bottles and all sorts of abominations. You will
frequently see a colored child, the canines not yet through
the gums, sitting up at the table taking its regular dinner
with the older members of the family, a dinner consisting
of rice, greens, bacon and pot-liquor, and perhaps other
abominations besides. ‘This child may stand this better than
the white child, but for all that it pays dearly for its smart-
ness.

As a result of this we find gastro-intestinal catarrhs in all
their forms, with reflex congestions of brain and other organs.
The data from the mortuary tables are unsatisfactory so far as

The Colored Race 135

knowing the exact state of affairs, because the diagnoses sent
in are from different standpoints, and symptoms put down
instead of diseases or pathological states. For example,
many Cases are put down as ‘‘convulsions”’ or ‘‘ teething ”’
which give us no record of the real pathological condition
present. Again, many appear as cholera infantum, which
covers a multitude of sins. My own experience has been that
real cholera infantum is rare among us, comparatively
speaking.

To try and clear up somewhat this unsatisfactory nomen-
clature, I have picked out of the mortuary tables the diseases
common during infancy and childhood and have arranged
them in three main groups.

I have in this table only put down those diagnoses which
are recognized as children’s diseases, and which are of suf-
ficient importance to be considered as factors in the death-rate.
Where there is doubt of the case being infant or adult, or, for
example, under enteritis, which, morever, only includes a
few cases, I have omitted them. ‘This table will give usa
fair idea of the relative mortality of the two races. They can
be divided into three groups. “ Congestion of the brain,”’
‘“convulsions,’’ ‘‘ meningitis,’? and probably the most of
‘‘dentition,’’ and ‘‘ worms,’’ are but different expressions for
closely allied pathological states of the brain and nerve centres.
Again, ‘‘cholera infantum,’’ ‘ entero-colitis;) “thrash,”
““inanition,’’ ‘‘ intestinal catarrh,’’ and ‘‘marasmus,’’ are
all related to the gastro-intestinal tract. And there is a third
group comprised under diphtheria, whooping-cough, mem-
branous croup, measles, and scarlatina, diseases recognized
as having a specific germ origin.

136 Eugene Rollin Corson

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Examining this table

‘“convulsions,

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a great

a little more closely, we find under
disparity between the two races, at
least three to one in favor of the whites. But when we turn
to ‘‘meningitis’’ and ‘‘congestion of the brain,’’ we find

The Colored Race 137

larger figures for the whites in both cases. This shows, I
think, that ‘‘convulsions,’’ ‘‘meningitis,’’ and ‘‘cerebral con-
gestion,’’ represent nearly the same thing, and taken together
we have 497 deaths among the colored against 300 among the
whites. So under ‘‘worms,’’ death probably came through
reflex cerebral trouble, or wasn’t ‘‘worms’’ at all. The diag-
nosis, of course, has no weight and we can merely conjecture
the cause of death. Put together we get a mortality about
double that of the whites, the figures standing 844 for the
whites against 1405 for the colored.

In the second group we find a great disparity between the
races under ‘‘inanition’’ and ‘‘marasmus,’’ while under
‘cholera infantum ’’ and ‘‘ entero-colitis ’’ the figures almost
correspond. Here, too, careless diagnoses have been made,
and with no proper understanding as to nomenclature. As I
have already said, cholera infantum is not a common disease
here, but is mistaken for intestinal catarrh and entero-colitis,
two diseases which are common here and which carry off
great numbers of colored children. Putting this group to-
gether, we find a mortality among the colored fully double
that among the whites.

Diseases of the nervous system stand second, and diseases
of the digestive system fifth and sixth in the order of frequency
as causes of death in the general mortality, and we can see
their influence here in the infant mortality. It is, however,
especially in this latter group that the colored so far exceed
the whites. To the practicing physician it is the first great
factor which is brought home to him in a comparison of the
vitality of the two races.

In the third group we have diphtheria, membranous croup,
scarlatina, measles, and whooping-cough. Diphtheria and
membranous croup are now generally regarded as one and
the same disease, and both are more common in whites than in
colored, one of the few instances where the colored can boast
of less susceptibility. And scarlatina which is so often
accompanied with diphtheria, is also less common among the
colored. But measles and whooping-cough are both very
much more fatal among them. Of measles the Census gives

138 Eugene Rollin Corson

the proportion of 9.1 among the whites to 17.7 among the
colored per 1,000 deaths from known causes, and our table
tallies well with these figures. Cases of whooping-cough be-
come broncho-pneumonia with brain complication and con-
vulsions.

As the mortuary tables do not give the proportion of infants
and young children, I have had to limit myself in the above
table to recognized infantile diseases, but from my own ex-
perience I can state positively that bronchitis, broncho-pneu-
monia, and pneumonia are common among the colored child-
dren and very fatal. Broncho pneumonia is the form most
commonly met with, and many cases put down as pneumonia
are, strictly speaking, this form of the disease.

The great heat of the summer, especially the vétéated heat
in the large cities, is a most potent factor in raising the death
rate among the infant population. This factor holds with
much less force in the southern cities from the fact that houses
are built more open, of one or two stories only,—I speak of
the homes of the poorer classes,—and the summers, while
much longer than the northern summers, have not that in-
tense heat, and most important still, the air is not so vitiated
as it is in districts where high brick walls prevent a proper
ventilation. Yet I see many cases of high fever among col-
ored infants and young children, with symptoms of cerebral
congestion and inflammation, and with a high mortality, due
to a direct exposure to the sun’s rays. ‘This isa danger which
is absolutely unheeded by the colored masses. It is a fre-
quent cause of death. ‘The whites are more careful in this re-
spect and suffer less. What is known assunstroke, zcfws solzs,
due to a hot wfated air, is not so common in the south as in
the close cities of the north and west.

As I shall show later, tuberculosis in the form of pulmonary
phthisis, carries off almost twice as many colored as whites.
This affects chiefly the adult population. With our increas-
ing knowledge of tuberculosis, we find its path of destruction
becoming broader and broader. At the time of Koch’s dis-
covery of the tubercle dacil/us, its field of operation seemed to
be limited to the lungs. It was soon found, however, that

The Colored Race 139

scrofulous glands, hipv-joint disease, Pott’s disease, and chronic
bone and joint affections, were also caused by the same germ.

The bacillus attacks the human body at all points, and
while the respiratory tract seems to bear the brunt of attack,
it is found that the percentage of infection here is by no means
so greatly superior to that of other organs or mucous channels,
In 1,000 autopsies, cited by Osler, there were 275 cases with
tubercular lesions, or over one-fourth. In the surgical clinic at
Wurzburg, among 8,873 patients, 1,287, or about one-seventh
were tuberculous, the bones and joints being involved in
1,037 cases. ‘The post-mortem statistics of Harris and others
show that over one-third —perhaps over one-half—of the peo-
ple who live to middle age have some form of tuberculous in-
fection. *

With these figures, and knowing how even with white chil-
dren the large majority of cases of meningitis are tubucular,
and how frequent it is in gastro-enteric lesions, how much
greater effect must the bacillus have in the more susceptible col-
ored child. Careful autopsies in the many cases of meningitis,
gastro-intestinal catarrhs, in ‘‘marasmus,’’ ‘‘inanition, ”’
‘‘convulsions,’’? and ‘‘dentition,’? would undoubtedly reveal
this malignant germ. We may almost define the term “‘ vital
equation ’’ to be the sum total of those forces which resist the
bacillus tuberculosis.

From what I have here given, hardly more than in outline,
the great influence of this high rate of infant mortality must
be very apparent. And it cannot be explained solely by the
fact that the colored population represents almost entirely the
poor and ignorant class, with all the evil influences of poverty
ignorance, dissipation, and general unhealthy living,—for it
must be remembered that there is a fair contingent of whites
in equal poverty, hunger and dirt,—but that the negro is more
susceptible, has less powers of endurance, and succumbs more
readily to the same diseases. Verily, the mills of God grind
fast! Even the high prolificness of the race under favorable
conditions could not keep pace with this mortality. On the
contrary, a lower birth rate as naturally follows a lesser vitality

* The Medical Record, March 18, ’93, p. 337.

I40 Eugene Rollin Corson

as a higher death rate. Man has no such compensatory proli-
ficness to meet a higher death rate as exists perhaps in some
lower forms of life.

Consumption heads the list of the causes of death. Its im-
portance becomes apparent when it is recognized that about
one-sixth of all deaths are due to this disease. Of its greater
fatality among the negroes there can be no question, and in
our southern cities where the two elements come together in
large numbers, the mortality among the colored about
doubles that of the whites.

The following table shows the mortality in our city from 1884
to 1892 inclusive :

1884) 1885|1886|1887\ 1888\1889|1890\1897\1892) Total.

WwW " 52| 49| 56| 59) 42 | 75) 63| 45] 494

98} 102] 107] I09g] 103] 99 | 125) 128} 114] 985

I have not thought it necessary to estimate the deaths per
1000 of population, for the exact population is an uncertain
element, and all figures must be only an approximation at
the best. It will be amply sufficient for our purpose if these
figures are viewed in a population where the whites are some-
what in excess.

A careful examination of the various board of health re-
ports of our different southern cities and states will all show
a remarkable uniformity on this point. To give anything
like a full report or this subject from our different cities
would swell this paper far beyond its proper limits, and I
shall merely state that having examined the reports from
Charleston, Richmond, New Orleans, Memphis, Nashville,
Chattanooga, Knoxville, Columbus, Atlanta, and Mobile, I
find that they tally well with our own tables.

The Tenth Census states :

‘The total number of deaths reported as due to consump-
tion during the census year was 91,270, being the greatest

The Colored Race I4I

number reported as due to any single cause of death.’’ (Vol.
XII, p. viii.)

And further :

‘It will be seen that the great majority of the deaths from
consumption occur between the ages of 15 and 65, the greatest
proportion in any decennium occurring between the ages of
20 and 30. The proportion of deaths between the ages of 15
and 35 is greater in the female than in the male. If we take
the group of ages from 15 to 65 and compare the number of
deaths reported as due to consumption with the total number
of deaths from specified causes at the same group of ages, we
find that the proportion is greatest in large cities, being, per
1,000,000 deaths, for males, 307,154, and for females, 338,571,
while in the rural districts it is, for males, 218,455, and for
females, 298,583. At the same group of ages in those regions
where distinction of color and percentage are made, the pro-
portions are, for whites, in each 1,000,000 deaths, males,
242,842, females, 302,046; for colored, males, 248,179,
females, 326,973; for those of Irish parentage, males, 309,-
507, females, 375,636, and for those of German parentage,
males, 249,498, females, 254,958. From these figures it
would seem that the proportion of deaths from this cause in
the colored race is but slightly greater than in the whites,
and that it is greatest of all in the Irish. At ages under 15 a
great excess of deaths from this cause is reported in the
calsred race."?), (Vol. XII, ps lix:)

These figures, I am sure, are very unreliable. The census
admits the imperfect returns from the colored, and a review of
Table III, p. xxi, Vol. XI, will show that the only returns
from registration cities, which give a comparative mortality
for the two races, are Louisville, Washington, Richmond,
Baltimore, New Orleans, and Charleston, very inadequate
returns to attempt anything like an accurate, comprehensive
survey.

Turn to the diagram on p. xxxviI, showing for whites,
colored, and Indians, the proportion of deaths from specified
diseaseS in 1,000 deaths from known causes, and it will be
found that the Indian mortality from consumption is almost

142 Eugene Rollin Corson

one-third greater that the colored, which, with our present
light on the subject, must be a great error. It simply shows
that the Indian returns have been more complete. And the
same applies to the excessive mortality among the Irish. The
cities drawn from have had this element of their population
especially large. All this but convinces me the more that we
can draw more accurate conclusions from a small section with
complete returns than a superficial survey of a large territory
with incomplete returns.

To the physician treating the disease among the colored, its
great fatality is but too apparent. I can’hardly recall a case
where I have stayed it, and they die without the slightest re-
sponse to treatment, and ina very short time. I have on
many occasions been able to trace its contagiousness, several
members of the same family going down in succession, the
same room and the same bed serving for all. No one can
doubt its contagiousness from such experiences. Soon after
Koch brought out his lymph, I tried it very prudently with a
mulatto but with such terrible aggravation that I never dared
attempt it again.

So far as my experience goes, I have failed to find among
the colored, many cases of local tubercular trouble, outside
the lungs, brain, or elementary tract, and I explain it by this
very great susceptibility. Local tubercular processes of skin,
bone, or mucous membrane, of any duration, presuppose a
certain amount of resistive power on the part of the body,
preventing its becoming pulmonary or general. It is kept
local. I do not believe the negro can long have a tuberculous
focus in any part of the body without its rapidly becoming
pulmonary or general. Further, my experience teaches me
that the mulatto is more susceptible than the pure negro. It
is with them that I have mostly seen those galloping cases
which defy all efforts to restrain.

I have never seen a case of lupus in the negro, of tubercu-
lous lesions of the bones I have seen but few cases. I can
recall but few cases of tubercular peritonitis upon the diag-
nosis of which I felt any confidence. Tuberculosis of the
genito-urinary organs I believe is more common, as following
in the wake of gonorrhceal infections.

The Colored Race 143

I have been assured by physicians who practiced among
them before the war, and when their physical condition was
so much better than it now is, that consumption was almost
unknown. The finding of any tubucular lesion in the lungs
at an autopsy was always a surprise. I shall, however, speak
of this later.

I have mentioned in my first paper the great susceptibility
of monkeys to tuberculosis when brought to this country.
The change of habitat and surroundings induce this predispo-
sition. Perhaps we had better say that greater exposure to
the germ coupled with impaired health from unnatural living
brings about this mortality.

Pneumonia stands third in the list of causes of death. It
is rare that I save a case of pheumonia either in adult or
child among the colored, and an inspection of the mortuary
records brings out a great disparity between the two races.
Here is a table of the deaths from pneumonia since 1884.

| | | | | | | Hal
YEAR. 1884\1885 1886 1887 1888 1889 1890 1897 1892) Total. |

a ——

| Wi 17] 9 | 16 | 15 | 22| 18] 7 | 23 | 20 147
Pneumonia. ... | | |
C| ) 33} 37 | 74 | 41 | 48 | 46 | 47 | 52 | 52 | 430

|
(

Here in nine years we have had 147 cases of pneumonia
among the whites and 430 among the colored, in other words
one white dies to three colored. The Census states, ‘‘’ The
comparative excess of mortality from pneumonia in the col-
ored race in the South has been known for a long time.’’
The disease with them rapidly assumes a general infection ;
there is a high temperature, typhoid symptoms, singultus, un-
consciousness, and death. Cases which recover are apt to
succumb later to tuberculosis.

Here are the figures put down to bronchitis and capillary
bronchitis :

144 Eugene Rollin Corson

| | | |
YEAR. 1884 1885 1886 1887 1888) 1889\1890\1891 1892, Total.
cae tres ct ls ee
de! 1 ea Wa) Rae sees al cee) mS eel) val
Bronehitish i) 2 | |
Cy) TO} Ga) 52), FA ame Se a7 13 | 20 | 108
1. | | |

W oO
Capillary Bronchitis

Aur zien’ 2 Za Mee 2 AZo
C| Oo} 5

Bronchitis is not common with us, and the doubt in the di-
agnosis is to be considered. The Tenth Census states it
causes a greater proportion of deaths in the white (17.3) than
in the colored (12.8). It is, however, a small factor in the
general mortality here in the South.

I give here a strange pathological table which shows the
difficulty we sometimes labor under from improper diagnosis,
or rather no diagnosis at all. There is an immense return, for
example, under ‘‘anasarca’’ which is simply a symptom, and
may result from heart, liver, or kidney trouble, and even
other troubles. Again, “‘ascites’’ is usually a symptom of
hepatic cirrhosis, but may occur from other abdominal condi-
tions as well as heart and kidney troubles. ‘‘ Cardiac dropsy’”’
gives us no idea of the real condition present. To offset this
I have added the cases of Bright’s disease, hepatic cirrhosis,
and heart disease, including under the latter term all speci-
fied diagnoses of heart trouble. Although the figures here
reduce somewhat the great disparity from ‘‘ anasarca,’’
‘‘ascites,’’? and ‘‘ cardiac dropsy,’’ it is very evident that the
colored are still largely in excess of the whites in cardiac
and renal diseases.

According to this table hepatic cirrhosis is more frequent —
among the whites, yet if we combine the figures with those of
ascites, the colored are in excess. Again it is the heart
troubles which add mostly to the mortality, and while even
here the negro mortality exceeds that of the whites, stillit is in
Bright's disease that we find the greatest disparity, and
greater still if we include a certain proportion of the cases

The Colored Race 145

under ‘‘ anasarca,’’ which we are justified in doing, I think.
Whichever way we turn the pathological horizon remains the
same, the colored looming up ever on the darker side of the
picture.

YEAR. 1884\r885 1886| 1887 1888 1889|7890\1891| 7892) Total.
Lib 0 FAN ike 0 el A Ve ie
INTUAS ATCO cones ols) Fe }
C530 8280-28) | sOuleioe eran een On 207
W!). bm IRE Ye) Oo I
INSCIteS Rigas) sre. }
Cc ; 2 25 S16n eo 7 33
Wi) o| 2 | o| o 2
Cardiac dropsy . .
Cc ZI ROR Wet es |o0, (ears 2 I 8
W 5-5 5 5 Ay |eioy |e 6 | 12 65
Bright’s disease. . } |
PACA Osi TOL eZ etah abot Ouycaey lee ele cag
W Zl 3 4 5 4 2. fe) 21
Hepatic cirrhosis . }
Cc OURO yard | I Coy eoae b|yo 6
MW 2A eta 255/25 | 20-1 oy |. 23 0) Tot 22). 184
Heart disease. . . }
CUA 2S 220s 27s RIT APO ne T5e le TSrleod

The Tenth Census states : ‘‘ These figures confirm the state-
ment just made that much of what thirty years ago was re-
ported as dropsy is now reported as heart disease ; and for this
reason, as well as to permit of a comparison presently to be
referred to, heart disease and dropsy are grouped together in
the present study. They caused a greater proportion of deaths
in the rural districts (59.7) than in the large cities (46.4), and
a greater proportion in the colored (64.5) than in the white
ES 3) eae eee an

In the Tenth Census Bright’s disease is not considered
separately but comes under ‘‘ Diseases of the Urinary System
and of the Male Organs of Generation’’ where the mortality
appears less for the colored. (White, 19.2, colored, 9.6). I
find no records in the Census of hepatic cirrhosis.

I give here a table showing the total deaths for white and
colored under ‘‘Undefined’”’ and ‘‘ Death without Physician.’’

146 Eugene Rollin Corson

YEAR. 1884) 1885 1886 1887 1888 1889 1890 1891 1892 Total.

if 5). 9) 8S 7 55/65) a7) eg) eae ee
| Undefined . . |
Cc 37| 70} 82] 94) 81, 133] 139] 100) 143] 879
Death Ww 13! 7| x4) 45| 7] xol 201 231 gl) 41S
without

physician. . C II9} II4, 240] 250) 182] 220] 301] 215] 208] 1849

This is another gloomy side to the picture. In the present
state of the world there is no denying the fact that the poor
cannot command the attention which the rich and the well-to-
do can. However willing the physician may be to care for
the sick poor the unsatisfactory conditions and surroundings in
which they live, conditions which he is not able himself either
by advice or more tangible means to remedy, must detract from
his interest in the case. Called toa patient in poverty and
dirt he feels that before his services can avail, before he makes
his diagnosis, prescribes, and gives his directions, the patient
needs a clean bed and a warm room, pure air and suitable
nourishment and attention, and directions properly carried out.
These all failing he feels utterly helpless to treat the case. He
can but make his diagnosis and prescribe, and go away.

Furthermore, there is apt to be among the masses of the
colored an indifference, real or apparent only, on the part
of the patient and family which must add to the physi-
cian’s indifference and must be a damper to help from
‘ outside. You see it in the patient and you see it in the

family, and even in the mother for her child. You are called
to a sick negro and he will hardly turn overin bed to face you
and answer you, and seems quite indifferent whether he
answers your questions or not, and you may go away without
knowing the real cause of your being sent for. This happens
so often that you soon come to look upon it asa racial charac-
teristic. "This explains how often you meet neglected cases,
cases of ugly wounds and ulcers, whose very loathsomeness
and discomfort, not to say real pain, you imagine would com-
pel them to seek advice and treatment. You see this in ven-

The Colored Race 147

ereal troubles which are allowed to goon until irreparable dam-
age has been done. For the same reason you rarely get a
malignant growth in its beginning; it is only when it has
gone so far that radical treatment is out of the question that
they finally see the physician. A carcinoma of the breast is
left until the axilla becomes involved and the violent pain
finally compels the patient to seek aid. A phagedenic sore is
allowed to reach a great size before it occurs to the poor patient
that it had better be looked after. This explains how often
the physician is sent for when the patient is moribund, how
often a death-certificate is demanded of the Health Officer for
cases which have never been seen by a physician. And here
are the figures to speak for themselves, 95 whites with a certi-
ficate of ‘‘undefined’’ against 879 colored with the same blank
certificate ; and 118 whites dying without medical attention
against 1,849 colored unattended, and in the last nine years,
and in a population not exceeding 50,000, and with the whites
between 5,000 and 10,000 in excess. And this indifference is
largely due to an insensibility to pain as well as a lack of
pride in physical well-being, pride in the possession of a com-
plete body with all its faculties operative, a quality possessed
by the higher order of man. This insensibility is seen in
minor surgical operations, in the parturient woman, and in
the neglected wounds and lesions, and the many little ills
which the more sensitive would seek relief from. The loss
of an eye or a member carries with it but little concern. And
all this is but that fatalism which has come to them from the
past.

In considering the high infant mortality I spoke of syphilis
in its effects upon premature and still-births, and I shall now
speak of the effects of the two venereal diseases upon the
adult population. We shall never get any figures which can
even approximately show us the real influence deathward of
these troubles. That they are all-potent in the white race must
be admitted, and their ravages among the colored become very
real to the physician practicing among them. The figures
which I have been able to obtain from our mortuary tables are
too small to have any value. I give them, however, for what
they are worth.

148 Eugene Rollin Corson

YEAR. 1884)\ 1885 1886 1887 1888|1889 1890 1891 1892 Total.

rarer OOM iO I I I Oo 6

Ay TE | AG er2n nS ei eT Owl On ne Om amos

Urethral stricture

ae | On ie OG Onl tele EL Om ae 3

OD), Oj] Eason ie SN Ae iON Nae ae 3

It is the physician only who can trace the pathological lines
leading to ill health and death whose course has been set, di-
rectly or indirectly, by these two diseases. They lie so much
beneath the surface, cropping out in so many unforeseen ways,
and at so many unexpected points, that the scientist is often
at a loss how to draw his pathological relief-chart. ‘There are
so many deep lesions of nerve-centres, viscera, and blood
vessels, which are the outcome of syphilis, contracted, per-
haps years before, that the disease has a most potent influence
in reducing the vital equation. And especially is this the
case when there is a history of neglect and intemperance,
factors which enter so largely into the disease among the col-
ored. Asa consequence we see all these stages in virulent
form; mixed and phagedenic sores primarily, followed by
severe secondaries, tubercular and pustular syphilides, violent
throat symptoms, iritis, and keratitis. Its tendency among
the women to produce abortion I have already mentioned. I
have not seen anything to compare with it among the whites.
And we see here not only the prospective loss of life but all
the dangers to the woman of the miscarriage itself.

The congenital form is so virulent that most of the infants
do not reach term. And with all these flagrant examples of
its lethality, there is probably as large a class dying of other
diseases where the vitality and the resistive power have been
so undermined by syphilis that they have succombed to a
strain which they could otherwise have borne.

The large majority of the cases of pyelo-nephritis and cys-
titis can be traced to the infection from gonorrhoea, and with

The Colored Race 149

women the serious complications of salpingitis and pelvic
peritonitis are traceable to the same cause. Both these fac-
tors must influence the colored, for this disease is always
serious with them, both from predisposition and the most
flagrant carelessness. I have never among the whites seen
such neglected cases of old strictures where urethral abscesses
and fistulae have formed, and where they have been con-
tent to go along without interference until, perhaps, ex-
travasation of urine has compelled them at the eleventh hour
to seek surgical help. One of these cases I have just oper-
ated upon and with fatal result, and hardly a month has
passed since I was called to a negro whom I found lying upon
a dirty floor dying from an extravasation of urine which had
taken place several days before, and for whom nothing had
been done or any surgical aid sought, although probably
twenty negroes in the settlement knew of his condition. I
mention this as showing that apathy, that indifference to
make a struggle for life, which is such a strong racial trait.

Of the returns from venereal diseases the tenth census
states: ‘‘In those parts of the country where the distinctions
are made between white and colored, and Irish and German
parentage, the proportions are, colored, 3.0, whites, 1.7,
Irish, 1.4, and German, 1.3 per rooo deaths from known
causes.’’ ‘The returns trom alcoholism and venereal diseases
are always very imperfect, and I give these figures for what
they are worth.

The negro once could boast of his unsusceptibility to
malaria and live secure in regions fatal to the white man.
But this exemption has been growing less and less complete,
and to-day the colored mortality from malarial and miasmatic
diseases is very much greater than it once was. The reasons
for this are various. In the first place a large part of this
mortality is from the mixed element which is more suscepti-
ble than the pure negro by virtue of the white admixture.
This is self-evident. In the second place, a less resistive
power naturally follows a less healthy physique. In the
third place, in the so-called malarial and miasmatic diseases an

150 Eugene Rollin Corson

enteric factor is apt at times to be an important element, an
element to which the colored are very susceptible, and which
is very fatal to them. ‘This has been plainly shown by sta-
tistics collected during the war among the colored troops.

The etiology of our prevalent fevers included under the
terms malarial and miasmatic is largely a jumble of mere
theories and opinions. ‘There are certain ones which seem to
be purely malarial, as we understand the term ; others seem to
be larval forms, masked by other elements vaguely called cli-
matic ; and others where a distinct enteric or typhoid charac-
ter is shown. We call them typho-malarial, a convenient
term, but one which prompts to laziness in our efforts to differ-
entiate more closely. All these fevers from the simple con-
tinued fever up to the severer forms of the malarial remittent,
of the bilious and hemorrhagic types, are constantly met
with among the colored. My experience has been that the
simple continued fevers, without any complications, run a
protracted course and are hard to break, while the severer
malarial remittents and the typho-malarial are very fatal.
Granted that the pure negro bears, comparatively speaking,
a charmed life in rice fields and uncultivated districts very
fatal to the white man, his much greater exposure swells his
death list, and this is the important point. ‘Typhoid fever
proper is a rare disease with us, comparatively speaking, and
when it occurs generally assumes a larval form, masked and
modified in one way or another by our climatic influences.
To these fevers the negro rapidly succumbs.

This year we have had more typhoid fever and remittent
fevers of various types than has ever been known in Savannah,
and a reference to our mortuary tables will show that, taking
all forms of fever into consideration, the colored mortality is
greater.

The Colored Race 151

YEAR. 1884 1885 1886 1887 1888 1889 1890 1891 1892, Total.
| | | |
W ibis fs I I OMI gy starlet |e 3
Bilious malarial. . }
8) eo tec 4 fo) 6
Wiis aton eto nl nOn (Ga), Lite TOs sTon eG) | 94:
Congestive malarial | } |
Aeeseerie ae leo AUR Flin, Fal won| SO
Wise ee Salers Qhuliy £3 Tes PoL2an alia eS tl So
Typho-malarial. . |
CRs lO! lero 2 @ 215 104/24 S9
WAREZ es LOLS eS LOu er Teer 70
Remittent malarial
c ES) 23° | 4k | 13 | 12 84 TA | Oo" | tg) 234
AVC coat bee! beTatits Bel Var ree bls. liom Ss
Typhoid fever. . . }
CUP LeoA ek Onl edalmvOnl Onl 12 slekne | hos
Wi ir e2i oO 2 2 I g 10
Intermittent malar. |
CRDr. 5)" r:| Aap Ou On ite i II
W 5| 6, 6 ates | LON 7 34
Malarialfever. . . }
CUP CONCER Wo) ult 22 dee ai aices| FOR) 3 60
WwW : I I 2
Hemorrhagic mala
(e Me eae seks Ono fo)
Wen 30: 5 I 3 oe 9
Continued malarial
c air 9| 4 2k
W EMI TE Tee erecuiny 1 I 4
Gastric fever .. . }
F Cu Joss| ko Oo | o o )
WwW eo es fo) ame O
Catarrhal fever . .
(e I I 2

This increased susceptibility to our continued types of
fever, as well as yellow fever, is a significant and interesting
point and will be brought out more fully when I show the
Consolidated Mortuary Record of Savannah from 1854 to 1883
inclusive. The above table also shows the uncertain state of
our nosology and the elasticity of our nomenclature. If you
can exclude typhoid fever you may call our continued types
of fever anything you please.

The tenth census states as to typhoid fever, ‘‘as causing a
somewhat greater proportion of deaths among the whites than
among the blacks, the figures being, for the whites, 33.9 and

152 Eugene Rollin Corson

for the colored 31.7 per 1,000-deaths from specified causes.
Up to the age of 15 the number of deaths from this cause is
proportionately greater among the colored.’’ And as to
malarial fevers: ‘‘ The proportion of deaths from these causes
is decidedly greater in the colored (48 3) than in the whites
(30.7), but this rule by no means holds good in all the grand
groups. The excess in the proportion of deaths from these
causes among the colored population occurs throughout all
the groups of ages.’’

As to the exanthematic fevers, I have already mentioned the
high mortality from measles among the colored children. We
havea history ofits malignancy in the Sandwich Islands, where
a large number of the population were swept away.

It has long been recognized that the negro is peculiarly sus-
ceptible to smallpox and that the mortality is high. Ina
small epidemic in 1891, 44 cases were reported to the Health
Officer, of which 4 were white and 4owere negroes. "There was
one death among the whites and 21 among the colored, that is,
a mortality of 50percent. ‘woof these were found dead and
seven 72 extremis, showing their usual carelessness and in-
difference. Smallpox was introduced into Savannah in 1865,
1866, 1867, 1875, 1876, 1882, 1884 and 1885, during all of
which times the disease went hard with the negroes, and they
who recovered were severely pitted. In vaccinating them
with lymph from the calf many suffered from severe sores
which were long in healing. As I have stated the colored
are not susceptible to scarlatina, or the allied poison of diph-
theria. ‘These diseases, moreover, are not common with us.

Cholera was brought into Savannah in 1866, resulting in 85
deaths among the whites and 211 deaths among the colored.
In 1867 there were 12 deaths from this disease among the
whites and 17 among the colored; and in 1868, 13 deaths
among the whites and 18 among the colored.

It is an interesting and significant fact that prior to emanci-
pation the negro was quite exempt from yellow fever. In
1854 there were in Savannah, from this disease 625 deaths
among the whites and only 10 deaths among the colored, while
in 1876 there were 771 deaths among the whites and 125 deaths

The Colored Race 153

among thecolored. In other words, in 1854 about 5 per cent.
of whites died of yellow fever, and only one-eighth of one per
cent. of colored, while in 1876 about 4% per cent. of whites
died and very nearly one per cent. of colored. Of course these
figures are only approximately correct as no account has been
taken of the exodus from the city at these times of peril. These
figures will be seen ina table giving the consolidated mortuary
record of Savannah from 1854 to 1886 inclusive, which I shall
introduce later, and which also shows the better physical
status of the negro before emancipation.

The great strides which have been made in recent years in
the etiology of disease through bacteriological research have
thrown much light upon susceptibility to disease, the predis-
position to certain morbid processes which some have more
than others. And this investigation helps as greatly in the
study of racial tendencies. In Europe where so much has
been done in this way geographical areas and nations living
under their different conditions can be mapped out on patho-
logical lines. This same work is being done in America, and
it cannot be very long before the colored race and its relations
to the inimical factors which produce disease and death, will
be better understood.

The susceptibility of the colored to tuberculosis is now gen-
erally recognized ; in other words they succumb to the bacillus
tuberculosis. To pneumonia, another germ disease, they also
quickly succumb, and on this line I have but to repeat what I
have already said in treating of the different diseases.

Recent researches are showing us that the various patho-
logical processes in the production of tumors, and especially
the malignant growths, are the direct outcome of minute or-
ganic forms, certain fungi and protozoa, and it cannot be long
before we shall know definitely the proximate causes of the
many varieties of carcinoma and sarcoma, diseases which are,
according to English statistics, on the increase. The figures
at my disposal are too small to have any value ; so far as they
go they show that the whites are still more liable to cancer
than the colored. The tenth census states: ‘‘In males the
proportion of deaths per 100,000 of living population is, for

154 Eugene Rollin Corson

the whites 20.54, and for the colored 5.85 ; in the females the
proportions are, for the whites 35.44, and for the colored
19.32.’’ From all I can learn, however, cancer is more com-
mon now than before emancipation when the vital equation of
the race was better. The cases I meet are very rapid, espec-
ially of the cervix uteri. ‘The most malignantsarcoma I have
ever seen was ina mulatto. Of osteo-sarcoma I have seen
but four cases, three negroes and one white. Of the two
cases of malignant lymphoma I recall, one was white and one
colored.

It is an interesting fact that just across the border from ma-
lignancy there are certain tumors to which the negro is very
liable. Of these the fibromata are especially noticeable ; the
uterine fibroids, fibroma molluscum of the skin, the tendency
to keloid tissue, all show this great fibrous-tissue prolifera-
tion. I have seen uterine fibroids of enormous size, and es-
pecially among the mulattoes. I am constantly called upon
to remove fibromas of the lobule of the ear caused by the irri-
tation of the earring. Fibromata of the neck are common,
starting from enlarged lymphatic glands, a frequent trouble
with them.

The formation of keloid tissue and hypertrophied scar-
tissue seems naturally to follow this connective-tissue prolifera-
tion. Ihave seen it mostly on the breast and neck following
operations. Erythema nodosum seems but the first step in
the pathological process producing fibroma moluscum. Ihave
seen but two cases of this trouble and they were both colored.

On this same line I may mention arterio-sclerosis which I
believe to be a not uncommon disease among the colored, al-
though rarely recognized as such. We get but few chances
for post-mortems which would help us so much in our patho-
logical tables. A further and more pronounced condition,
atheroma, is constantly found. I have recently had a most
remarkable case of this kind in a negro about fifty-five
years old who looked seventy, and whose brachial artery was
subcutaneous and outside the deep fascia from the axilla to
the elbow. By pinching up the artery with the finger all cir-
culation in the arm was controlled. Its atheromatous condi-

The Colored Race 155

tion was very evident. The large contingent put down as
dropsy, with heart and kidney complications, has probably in
many cases an arterio-sclerosis basis. In my own practice I
have seen more cases of aneurism among the colored than
among the whites. Dr. A. Corre in his voluminous work
(Traité clinique des Maladies des Pays Chands, Paris, 1887),
writes, p. 463, in a foot note, ‘‘nous avons été surpris du
grand nombre d’anévrysmes artériels qu’on rencontre chez les
noirs et les mulatres.’’ Cerebral apoplexy and paralysis have
a bearing here and I have drawn up the following table show-
ing the deaths from aneurism, apoplexy, and paralysis.

YEAR. 1884 1885 1886 1887 1888 1889|1890 18911892) Total.
Oh Eh Ont Ons Out 2) ooOu ike 2 2 7
Anelirism. .... ;
Le: i 2 OR |e Oh nar Tes (|e 2 ayer I 9
TNA 8) RN al la Wa a AR es 46
Apoplexy'; <°:'..
Cc AU) teh eae ya sal NSS eeu IY 52
WW 9) 266] Ge |) Gel | aes | aegi i ataaly aes 9 | 15 10g
Raralysis: srs) «=.
Cc PSG pyle LEW 200) EL Ff al eatp alli ca 113

These figures are quite too small to draw any conclusions
from. ‘The colored at least keep well apace with the whites.

According to the tenth census the deaths from apoplexy
and paralysis are greater among the whites (35.1) than among
the colored (15.9). I have more confidence in my own figures.

The negro shows a tendency to suppuration ; in other words,
he has less resistive power against those purifacient cocci
which cause the ordinary suppurations in the body. On the
slightest provocation he has glandular swellings followed by
abscesses in inguinal, cervical, and axillary glands, acute
abscess of the tonsil, onychia, and suppurative foci generally.
The tubercular syphilide is frequently followed by a pustular
one ; variola produces marked suppuration and pitting. Cuts
and contusions often result in suppuration. All this shows a

156 Eugene Rollin Corson

lack of resistive power against certain germs, especially the
staphylococcus, and is another minus factor in lowering the
vital equation. While not directly causing death, it may do
so indirectly and appear in the mortuary records under other
headings. Corre, above quoted, also mentions this predispo-
sition, having met with many cases of cold abscess and sup-
purative lymphatic glands.* In treating of hepatic abscess
he states that while more common with Europeans the relative
mortality is greater among the negroes. He states further
that the negro, when in Africa and not transported, enjoys
considerable immunity against hepatitis, but that outside his
own country, even if ina similar climate, he loses this im-
munity andshows a mortality equal to, or greater than, that of
the European.t

I have never seen a case Of delirium tremens in the negro.
I think this is easily explained. We usually find delirium
tremens in those of tough fibre who can stand that heavy and
prolonged drinking necessary to develop the disease. The
negro cannot stand this heavy and prolonged drinking. He
is soon done for and becomes so overcome by the drug that he
must let up for a while ; or he becomes disorderly and com-
mits some violence which sends him to the barracks and the
chain-gang, where his stomach has rest and where he is en-
abled to pick up again. The evil effects of alcohol then are
seen in acts of violence, in the inflammatory troubles which
follow exposure while under the influence of the drug, and
those congestions and inflammations of the thoracic and ab-
dominal viscera which can be traced directly to alcohol in all
its forms.

Dr. Billings writes: ‘‘The proportion in those parts of the
country in which the colored distinction is made is much
greater among the whites than among the colored, and where
the distinction of parentage is made, it is much greater among
the Irish than among the Germans, the figures being for the
Irish 6.7, for the Germans 2.7, and for the colored .7 per 1,000
deaths from known causes. A large proportion of the deaths

* Opn Cit. ip. 466:
it Op. ‘eit.,“p. 797.

The Colored Race 157

reported as due to alcoholism occur in connection with delirium
tremens and this form of disease is rare in the colored race,’’*

To the physician in active practice, however, it is not nec-
essary to see alcoholism in the form of delirium tremens to
realize its evil effects. It is seen in so many side channels as
inciting to congestions, catarrhal inflammations, fibrous proli-
feration, and a general lowering of the vital powers. It often
turns the scale when the patient is fighting for his life. It
diminishes his working capacity and mental acumen. ‘These
evil effects are but too plainly seen among the colored, so that
a review of the deaths from delirium tremens can in no way
show the extent of the evil. The large number of cases of
“‘dropsy’’ and ‘‘heart disease,’’ and evident arterio-sclerosis,
is probably in a measure due to alcoholism. It must be re-
membered, too, that it is only the cheaper spirits they can buy,
largely composed of methyl alcohol. Alcoholism directly
and indirectly has always been an immense factor in the mor-
tality of the lower classes. It played havoc among the Amer-
ican Indians, and the same story comes to us from India.

The question of insanity is an interesting one. In search-
ing through the records at the Ordinary’s office, I find there
have been 84 cases of insanity among the whites and 133
among the colored since 1879. Through the courtesy of Dr.
T. O. Powell, Superintendent of the State Lunatic Asylum at
Milledgeville, I have some interesting figures bearing on the
subject. In 1860 there were only 44 insane negroes in the
State in a population of 465,698, or one insane negro to every
10,584. The Census of 1870 showed 129 insane negroes in a
population of 545,142, or one colored insane to 4,225. The
census of 1880 gave 411 colored insane, or one to 1,764 of the
population.

All this shows a great increase in the liability to insanity,
and while it is still more frequent among the whites, the rate
at which the colored have increased in this direction promises
to outstrip the whites at no very distant day. And this is to
be expected when we consider the greater strain of to-day
brought to bear upon them, the evil influences of syphilis,

* Vol. xil, p. 797.

158 Eugene Rollin Corson

alcoholism, and other irregularities. The cases I have seen
have been mostly acute mania, of a religious type. Dr.
Powell states that he has never seen a case of paresis in the
negro. I have seen several cases of epileptic imbecility among
them. Hysteria is common among the women, and the most
typical cases of hystero-epilepsy I haveever seen, three in all,
if my memory serves me, were among the colored. The emo-
tional side of the negro is pronounced; you see it in all their
gatherings, especially the camp-meetings, where many work
themselves up into a religious frenzy.

Speaking of miscegenation I wrote in my first paper: It
would be an interesting point to know the percentage of this
mixed-element to the pure African. Iam persuaded that it is
much larger than generally believed. The census unfortu-
nately has made no distinction inthe enumeration. Itis, how-
ever, a distinction which should be made, and any correct re-
turns would point to many significant tendencies, and bea
point d’ appud for our argument. This mixed-element indicates
the fusion and assimilation going on. ‘That it bears the same
social stigma as the darker color shows that the barrier be-
tween the races is a social but not a physiological one, for
underneath this barrier miscegenation goes on through many
channels. ‘This new product is a large one though it is large-
ly unstable.

Miscegenation will go on in the future as it has gone on
inthe past. Its illegality will be no bar to it, though the
process of fusion may be retarded. To my mind race predju-
dice will not be in the years to come what it has been or what
it now is. ‘Time alone, throwing the days of bondage further
back into the past, will in itself modify and soften these feel-
ings of race, especially when, by the gradual fusion, the color
will become lighter and the mixed-element will exhibit qual-
ities allying it more and more to the Caucasian. It will not
be in our day, of course, nor in the next generation; it may
take centuries, but it will come.”’

The question whether the mere mixing of the races in
itself results in an unstable product is one which I have
not been able to answer to my own satisfaction. My

em

The Colored Race 159

Opinion is that this instability is largely the direct inher-
itance of a weakness and degeneracy of one or both par-
ents, as naturally follows the laws of reproduction and
inheritance. Still there seems to be a factor outside of
this, a factor dependent upon miscegenation itself. The mix-
ing of different nationalities of the white race often ap-
pears to strengthen the new products, but the ethnic chasm
which separates the Caucasian from the African is too wide
for nature to bridge successfully. The bridge is but tempor-
ary and gives way to the strain it must eventually bear.
Whatever the true explanation may be, the fact remains that
this mixed-element is an unstable one with a high rate of
mortality.

In the six years which have gone by since I wrote the above
I am still more convinced of the poor vital equation of this
mixed element. ‘Their susceptibility to tuberculosis is cer-
tainly very great, and I have attempted to show what a large
factor thisisin the general mortality. Wesee it in their children,
in the lowered prolificness among the women, in the greater
tendency to dystocia, in the frequency of diseases of the
uterus and adnexa. And in spite of the fact that it represents
a better class socially, who lead better lives and live altogether
more hygienically. I have noticed thisin their churches, and
social and political organizations. ‘The congregations of their
episcopal churches are largely of the lighter color; they have
more social pride, and represent altogether a better living
class, and yet withal their vitality is poor.

This element, I firmly believe, is greatly on the increase.
Attempts by the census to show the proportion of pure blacks
to all the shades of admixture with white blood have signally
failed, and we must wait another decade before we can have
any reliable figures on this point. For some time I have
looked upon this miscegenation as a reducing agent, chemi-
cally speaking ; it withdraws vitality from the pure negro and
produces a new compound which is even less stable.

Though not bearing directly upon the question of vitality it
may be interesting to compare the deaths of the two races
from accidents and violence. Here are the figures for
Savannah at least :

160 Eugene Rollin Corson

YEAR. I884 1885 1886 1887 1888 1889 1890 1891 |1892| Total.
|

Wy 3 9)23 6 | 18 8 | .31.|.37. || 32) Sees
Death from acci+-
dent and violence

[
Che} 16)) Kop | X77 | TO a EST 3i | 29a 20g Baa eel

Though there is no great disparity the figures are in favor of
the whites. The tenth census states: ‘‘In that part of the
country in which the color distinction is made they caused
among the colored 67.6 and among the whites 43.8 per 1,000
from all deaths from specified causes.”’

I have thus far attempted to show the various pathological
lines by which this high mortality among the colored is
reached. Of its incompleteness I am only too painfully
aware, for we have not vet the figures which can enable us to
draw very sharp lines. The attempt has been made in the
tenth census, and however much we may admire the evidence
of work and care in the elaborate tables and maps, we feel
that much is still lacking, and especially so on the question
before us. I believe that a collective investigation among the
physicians practicing in large colored communities would be
the best method at our command at present, and it is
this belief which has prompted me to give’my own expe-
rience in atypical southern city of a sufficient population to
draw fairly reliable conclusions from. ‘This method seems to
me less liable to error than the more superficial view of a
large geographical area, with many gaps to be filled in.

I introduce here a table I gave in my first paper of the con-
solidated mortuary record of Savannah from 1854 to 1886 in-
clusive, which, with some allowances, gives a fair idea of the
state of affairs in our city.

CONSOLIDATED MORTUARY RECORD OF SAVANNAH, GA., FROM
1854 TO 1886 INCLUSIVE.

From 1854 to 1870, and from 1870 to 1879, no reliable census is attain-
able ; consequently I have estimated the increase of popniation pro rata
yearly during said interims, and have computed the annual ratio of
deaths per 1,000 of population upon this status. Although not nymer-
ically correct, the estimates are nearly enough so to give valuable sta-
tistical information.

The Colored Race 161

This table proves conclusively that prior to the freedom of the African
race in the United States their death ratio was smaller than that of the
white race.

| Ratio per 1000 of
mes. POPULATION. No. OF DEATHS. Population.
Whites Blacks. | Whites.| Blacks. | Whites. | Blacks.
SHAN 12,46 8,961 122 308 97.9 34.3
GH Gwe
E55) ||) wees et een, Th Aaah 202, |)! gag’ | vane
1856. || ¢.24 oe QR 466 297 36.4 31.2
eh , 1 D4, 3 boy 376 264 29.0 27.0
Oy : 235 gs 592 262 45.2 26.1
1859 . ec oe 430 273 32.4 26.5
186° ; 2E8e “Mas 474 282 B53 26.7
Bee UUM Ge Mica BBW See | ogre vane lh tale
ee | las | lee 459 | 389 | 337 | 342
1004 . on9 (ons 47 44 53-3 39.3
ose : E Bs E Bes 1,202 819 84.8 68.9
‘ aos soa 530 gI2 37.0 75.0
171867 . are eae 476 594 32.8 47.3
t*1868 . ase Aso 498 581 34.0 45.8
*1869 . J 25 DE 423 429 | 28.6 33.1
Ratio per 1000 of
ais POPULATION. No. OF DEATHS. Population.
Whites Blacks. | Whites. | Blacks. | Whites.| Blacks.
1870. 14,938 TAIT 450 576 30.1 43.5
ae reti ct) (Mie Hikes
187I . ) | oa Bi = Sa 526 606 34.4 45.1
1872 | Blom im 264 519 636 33-4 46.5
1873 |" ao | x2 558 789 34.0 56.1
1874 . Bp oag vil Space 394 642 24.5 45-5
ee $3 os Seb 2 e 394 See zis ace
1907 Soag (8 o-4 1,205 904 70.0 7:
*1877 | Ber poe 5 Boe 375 623 py 42.2
1878 . ie ore oa 2 cae 362 626 21.0 41.8
nw VOD WH ae axa
1879 . 17,493 15,163 416 686 27) 45.1
1880 . 18,229 15,019 462 885 25.3 58.8
1881. 19,114 15,765 557 903 29.1 7 /se
1882. 20,514 16,819 375 740 18. 43-9
1883. 23,839 16,652 488 659 20.4 39.5
1884. 25,362 19,150 469 703 17.9 36.7
1885 . 25,720 19,111 333 659 13.7 35-4
1886 . 26,675 19, lI 458 953 7a 49.8

162 Eugene Rollin Corson

*Yellow fever 1854—Deaths, whites 625, blacks 10. *1858—Deaths,
whites 112, blacks 2. *1861—Deaths, whites 4. *1864—Deaths, whites
14. *1865—Deaths, whites1. *1868—Deaths, whites1. *1869—Deaths,
whites 1. *1876—Deaths, whites 771, blacks 125. *1877—Deaths—
whites 4. {Small pox introduced by United States troops 1865, 1866,
1867. +1875, 1876, 1877, }1882—One case. +1884—Two cases. +1885—
One case. No accurate account can be given as to deaths ; it was very
heavy in 1865 and 1866. {Cholera brought from New York by United
States troops. 1866—Deaths, whites 85, blacks 211. {1867—Deaths,
whites 12, blacks 17. {1868—Deaths, whites 13, blacks 18.

I am indebted to compilation of our honored townsman, Dr. W. Dun-
can, for tabular statement of deaths from 1855 to 1869 inclusive.

J. T. MCFARLAND, M. D., Health Officer.

In this table we find that from 1854 to 1863 more whites
died proportionately than colored. Then from 1864 to 1876
the white mortality was still in excess of the colored. The
year 1866, however, was the turning point, for with the excep-
tion of 1876, the year of the yellow fever, the colored have
greatly exceeded the whites in mortality.

From 1880 the returns show that twice as many colored as
whites die in proportion to the population. Some years show
an even greater mortality. In 1880, in the ratio per 1000 of
population, the figures stand 25.3 for the whites and 58.8 for
the colored ; in 1882, 18.2 for the whites, and 43.9 for the col-
ored ; in 1884, 17.9 for the whites, and 36.7 for the colored ;
in 1885, 13.7 for the whites, and 35.4 for the colored ; in 1886,
17.1 for the whites and 49.8 forthecolored. This table shows
conclusively, for Savannah at least, that prior to emancipa-
tion the death rate of the colored was less than that of the
whites, but that since their freedom their mortality has greatly
exceeded that of the whites. It would be indeed valuable
for our subject could we get similarly prepared tables from
other parts of the country.

To this I now add a table which continues the figures up to
1892 inclusive, which shows the same high rate of mortality
among the colored, a mortality, which, making all due allow-
ance for error, about doubles that of the whites. JIomit, how-
ever, the estimated population and the ratio per 1,000 deduced
from it as the figures are largely guess-work. It is sufficient
to. remember that the population is now about 45,000, and that
the whites exceed the colored by about 5,000.

The Colored Race 163

—
No. of Deaths.
YEAR ’
White. Colored.
| 1887 458 798

1888 366 665
1889 384 685
1890 479 870
1891 464 746
1892 468 834

=|

In my first paper, in conjunction with the above consolidated
mortuary record of Savannah, I composed the returns I was
able to get from Charleston, New Orleans, Richmond, Nash-
ville, Chattanooga, and Knoxville, and I found results tallying
fairly well with those of our own city. I give here a table
showing the relative death rate in six cities, where there is
a sufficient colored population to make a comparison, for the
census year 1879-80.

Deaths per 1000 of

aie: living population.
Louisville. . eee See
Washington . ma ; won
Richmond. . ts \ ae
Baltimore. . ca pate
New Orleans. ‘ \ rape

5 | .

W 23.78
Charleston C \ fae

I have not been able to obtain a sufficient number of
reports from other cities to carry out, as it should be done, a
comparative statement of the mortality records, nor does it
come within the scope of this paper to do so. It is sufficient
for my argument that they all bear testimony to a large mor-
tality among the colored and greatly in excess of the whites.
Of course I am aware that the mortality falls outside the

164 Eugene Rollin Corson

cities ; and the reasons for this are quite too apparent that I
should elaborate them here. ‘The one important point in my
argument is, that the negro cannot stand the sharp competition
in the cities, that when thrown directly in the struggle for
existence with the white race he cannot hold his ground, that
the more densely populated the country becomes and the
fiercer the struggle, the more he must lose ground, and that
his greater mortality shows us the extent of his defeat. -

Having shown, asI hope, this greater mortality and the va-
rious ways by which it is brought about, it will be interesting to
see how this accords with the teachings of ethnology and biol-
ogy which treat the subject from the standpoint of the natural-
ist. It is only in this way we discover the relationships of or-
ganic forms from the lowest to the highest, and the laws gov-
erning the survival and death, the increase and decrease of
species and races, with man as a part of the animal kingdom.

And first and foremost, the inferiority of the negro as com-
pared with the Caucasian.

It would hardly seem necessary to dwell at any length upon
the conditions which stamp the African race as one greatly in-
ferior toourown. When writers like Mr. Tourgée ignore this
fact, and not only ignore it but seem to put the two races on
an equality, it is not necessary to discuss the question with
him; but for the sake of our argument we shall indicate
briefly the salient points of difference between the Caucasian
and the African as taught us by ethnology and comparative
anatomy.

The pure negro is the representative of a race whose nat-
ural habitat is the African mainland. ‘Though spread over a
large area it shows a greater uniformity in physique and moral
type than is to be found in the other great divisions of man-
kind. ‘To the ethnologist it marks a type the lowest in the
scale of humanity.

A. H. Keane gives us the following points as indicating
the low type and nearer approach in body to the quadrumana
or anthropoid apes :

‘(r) The abnormal length of the arm, which, in the erect
position, sometimes reaches the knee-pan, and which, on an

The Colored Race 165

average, exceeds that of the Caucasian by about two inches ;
(2) prognathism, or projection of the jaws (index number of
facial angle about 70, as compared with the Caucasian, 82) ;
(3) weight of brain, as indicating cranial capacity, 35 onnces
(highest gorilla 20, average European 45); (4) full black eye
with black iris and yellowish sclerotic coat, a very marked
feature ; (5) short, flat snub nose, deeply depressed at the base
or frontal suture, broad at extremity, with dilated nostrils
and concave ridge ; (6) thick protruding lips, plainly show-
ing the inner red surface. (7) very large zygomatic arches—
high and prominent cheek-bones ; (8) exceedingly thick cra-
nium, enabling the negro to butt with the head and resist
blows which would inevitably break any ordinary European’s
skull; (9) correspondingly weak lower limbs, terminating in
a broad flat foot with low instep, divergent and somewhat
prehensile great toe, and heel projecting backwards (‘lark
heel’); (10) complexion deep brown or blackish, and in
some cases even distinctly black, due not to any special pig-
ment, as is often supposed, but merely to the greater abund-
ance of the coloring matter in the Malpighian mucous mem-
brane between the inner or true skin and the epidermis or
scarf skin; (11) short black hair, eccentrically elliptical or
almost flatin section, and distinctly woolly, not merely frizzly,
as Richard supposed on insufficient evidence; (12) thick
epidermis, cool, soft, and velvety to the touch, mostly hair-
less, * * *; (13) frame of medium height,
thrown somewhat out of the perpendicular by the shape of
the pelvis, the spine, the backward projection of the head,
and the whole anatomical structure ; (14) the cranial sutures,
which close much earlier in the negro than in other races. *
These anatomical characteristics are well known to every
careful observer ; they mark a distinct race of mankind and
show conclusively an inferior type. The natural habitat of
the race is in itself indicative of its inferiority, for whatever
Egypt may have been in the past, and history certainly points
to a high order of civilization ages before the Christian era,
Africa for centuries has been the home of the savage. It is

* Encyclopedia Brittanica, Article ‘‘ Negro.’

166 Eugene Rollin Corson

the cranial and facial characteristics which have the direct
bearing upon the points at issue. The prognathism, the
facial angle, the weight of the brain, the thickness of the
skull, and the early closure of the cranial sutures, all point to
a lower intellectuality and an inferior nervous system.

The negro infant starts apparently with a great advantage
over the white child; it is more precocious in every way, and
maturity comes sooner. But this rapid growth soon reaches
the end of its tether, and at a time when the negro has at-
tained its full growth, the white child is but beginning to de-
velop qualities which in time advance it to a point unattain-
able by its less fortunate rival. Even when educated up to a
certain point by the efforts of, and association with, a higher
race, the mind is in acondition of unstable equlibrium which
reverts in time back to its original level when the civilizing
influences have been withdrawn. Throughout the animal
world whenever artificial conditions have been brought to
bear to produce results different from those which nature at-
tains by her slow methods, the new products when left to
themselves fall back to their original starting points, or but
little in advance of them. It will be like the stone of Sisy-
phus. In the two centuries and a half of association with the
Caucasian the race in certain directions has been much bene-
fited by the higher civilization. If these associations were to
be suddenly and completely cut off, and the race were to be
left to its own resources, its future would be a retrogression
rather than an advance.

In this connection let me quote from Sir Spencer St. John,
a most impartial and moderate critic, who, in his ‘‘ Hayti or
the Black Republic,’’* gives usa dismal picture of the state
of affairs in that unfortunate country. I am glad to find my
own views substantiated by so good an authority.

‘“The vexed question as to the position held by the negroes
in the great scheme of nature was continuously brought before
us whilst I lived in Hayti, and I could not but regret to find
that the greater my experience the less I thought of the capa-

* Hayti or The Black Republic. By Sir Spencer St. John, K. C. M. G.,
New York, 1889.

The Colored Race 167

city of the negro to hold an independent position. As long
as he is influenced by contact with the white man, as in the
southern portion of the United States, he gets on very well.
But place him free from all such influence, as in Hayti, and
he shows no signs of improvement; on the contrary he is
gradually retrograding to the African tribal customs, and
without exterior pressure will fall into the state of the inhabit-
ants of the Congo. If this were only my own opinion, I
should hesitate to express itso positively, but I have found no
dissident voice amongst experienced residents since I first
went to Hayti in January, 1863.

‘I now agree with those who deny that the negro could
ever originate a civilization, and that with the best of educa-
tions he remains an inferior type of man. He has as yet
shown himself totally unfitted for self government and incap-
able as a people to make any progress whatever. ‘To judge
the negro fairly one must live a considerable time in their
midst, and not be lead away by the theory that all races are
capable of equal advance in civilization.”’ p. 134.

I am speaking now of course of the race without any ad-
mixture of white blood ; with it the problem becomes a differ-
ent one ; the intellectual level rises, and the more this element
enters into the combination the nearer the new product ap-
proaches the Caucasian. We may meet with the intellect of
an Alexander Dumas, or Dumas, fils, though I think the pro-
duct arare one. It is in the large mixed-element that we
find examples of those who have risen above the multitude of
their race and have shown qualities which ally them closer to
the superior race. To writers like Mr. Tourgée this factor of
miscegenation does not enter at all into their calculations.
They speak of Whites and blacks as though it were a question
of color only, with a sharp color line separating the two races,
a mere difference in the amount of pigment in the Malpighian
layer. One would think from their treatment of the subject
that equal political rights and equality before the law meant
equality moral, spiritual and intellectual. They lump to-
gether the entire colored population asa homogeneous mass
to be measured by one standard. ‘They bring forward ex-

168 Eugene Rollin Corson

amples of colored men who have attained considerable reputa-
tion, and have shown, perhaps, fine mental parts, to show the
beneficial influences of education and civilization upon the
African, and the possibilities of the race, and ignore the in-
fluence of the white admixture, and the credit due thereto.

And with this evident inferiority what can we learn further
from biology ?

A deterioration in physique may be looked upon as the
natural result of the many influences at work arising from the
transporting of the race to a foreign soil to be thrown into the
struggle for existence against a superior race, a struggle which
can have no ultimate issue but defeat, and by defeat I mean
an inability to maintain the distinctive characteristics of the
race. ‘The struggle will be a slow process of fusion by which
the weak and unstable elements will disappear while that
which has any permanency will become so blended with the
dominant race as to lose its individuality. Of the stable and
the unstable the latter is by far the greater; its instability
can be measured by the physical degeneracy. Even to-day to
call the colored race the African race is something of a mis-
nomer because it has undergone many modifications. A
change in language, in soil, and in climate, a change of sur-
roundings and associations are potent influences to eventually
destroy the original African traits. This struggle may, per-
haps, be better described as a process of assimilation by which
the elements ill-adapted to the growth of the dominant race
are thrown off, while that which is assimilable becomes grad-
ually absorbed into the main growth.

Let us glance a little more minutely into these factors of
change anddecay. The changeof habitat alone, a change of
soil and climate, has a certain influence. Man, like the ani-
mals and plants, bears the stamps of geographical areas. A
race indigenous to a certain country acquires through many
generations characteristics the formation of which can be
traced to climatic and telluric causes. One of the most inter-
esting departments of biology is the study of the geographical
distribution of animals and plants ; and man is no exception,
for in him, too, we can trace the influences of the ground he

The Colored Race 169

treads and the air he breathes. And when man is removed
from his home to a distant country, and is brought under dif-
ferent climatic and telluric conditions, he feels the change in
proportion as the new environment differs from the old.
Nature at once goes to work to adapt the new-comer to his
new surroundings. ‘The greater the change the harder the
process of adaptability and the greater the waste and the loss
of life. The medical histories of wars in distant climes in
which Europeans have figured show that the loss of life from
a new environment has often equalled, if it has not exceeded,
that from the casualties of war. The Esquimaux can as
little live in the tropics as the Hottentot in the polar region.*

Now while the change of the African to America has been
more in longitude than in latitude it must still have an influ-
ence in modifying the race. The negro without any other
modifying influences would be a different man five hundred
years hence from the one just transported from his natural
home.

But a factor much more potent is the struggle for existence,
and not only a struggle within the race but a struggle outside
with a superior race. There is no law in the physical world
more relentless than this very struggle for existence and sur-
vival of the fittest. From the cradle to the grave it is one
continuous fight with man and the elements. It is a struggle
for mere living, a struggle for ease and comfort, a struggle
against exposure, privation and disease ; and in this struggle
the weaker die and the stronger live. We may talk of uni-
versal brotherhood, but the stronger will rise and rule and the
weaker will go to the wall. The denser the population the
thicker the fight. It is in the great cities that we see this
struggle at its fiercest—the poorer and weaker on one side,

*An interesting example among the lower animals of the fatal influ-
ences of a change of habitat is seen in the monkeys brought to this
country. They almost invariably die from consumption. I once ex-
amined the bodies of a number of monkeys from our menageries and
zoological gardens, and in every case I found pulmonary tuberculosis in
all its stages. The change from the pure air of the forest to the con-
fined and vitiated air of our centres of population is fatal to them.

170 Eugene Rollin Corson

and the stronger and richer on the other. It is the difference
between poverty, hunger and dirt, and ease and comfort and
luxury, and a difference greater still, a difference in the sick
list and in the death rate ; for with poverty and close quarters,
with dirt and exposure and crime, come sickness and death.
The situation of the colored race is a peculiar one. After
being carrled off from their home to a distant land and held
in bondage for years, they are suddenly set free and thrown
upon their own resources. That they have even in a measure
stemmed the tide is indeed to be wondered at. During
slavery it must be conceded, I think, that so far as the merely
physical man was concerned they were better off. Such bondage
would be well physically for a large portion of the white race.
They were out of the struggle for existence with their super-
iors ; they were cared for like so many valuable animals ; it was
to the interests of their owners that they should be; though
worked hard, they led regular lives; the dissipations and ex-
cesses which enter into the life of a free people they were with-
held from ; when sick they had the best medical attention ob-
tainable ; and all the information which I have been enabled to
obtain has satisfied me that the race was a healthy one, even
healthier in the main than the white.

But since the war and emancipation things have been re-
versed. Suddenly thrown upon their own resources their
struggle began in the midst of things; freedom gave loose reins
to the animal ; the doors were opened wide to the vices and ex-
cesses of a material civilization ; their life became an irregular
one ; these vices and excesses which like parasites have grown
with the growth of our civilization, became a part of their life,
and these parasites in their new soil have shot down their roots
deeper and have obtained a firmer foothold. This has been
the history of the introduction of civilized vices into all un-
civilized communities ; whiskey, good or bad, certainly dis-
agreed with the poor American Indian, and to-day in India it
is playing sad havoc with the multitude. The explanation is
that, however small self-control over the appetites exists in the
Caucasian it is practically wanting in the savage who drains
his cup to the dregs. It is bad enough for the white man but
it is worse for his inferior.

The Colored Race I7I

Certain writers, like Mr. Tourgée, for example, in their pre-
dictions for the future, rely upon ‘‘ the greater prolificness of
the negro,’’ as though the prolificness of any plant or animal
were a fixed quantity. But the naturalist knows within what
wide limits the prolificness of any plant or animal may vary.
That under natural and favorable conditions this prolificness
shows a certain rate of increase, and that, on the contrary,
when the natural conditions are removed and inimical factors
are brought to bear, the rate of increase falls, and may con-
tinue to fall to complete extinction. In the study of different
organic forms we find of course great differences in the proli-
ficness, depending upon certain laws which have been fairly
well worked out.

No one, to my knowledge, has more clearly brought this
out, and especially so in its bearings upon the multiplication
of the human race, than Herbert Spencer. In his Principles
of Biology, Part VI, he treats of the laws of multiplication, an
elaboration of a paper which originally appeared in the West-
minster Review for April, 1852, entitled ‘‘A Theory of Popula-
tion deduced from the General Law of Animal Fertility.”’
Here he points out the antagonism between growth and sexual
and asexual genesis, between development and sexual and
asexual genesis, between expenditure and genesis, and between
nutrition and genesis. He shows us how the vitality of any
organic form divides itself between individuation and genesis,
between maintaining individual life and increasing the species.
He shows us that where these forms are minute and low in
the organic scale, with little or no differentiation of parts, and
where individuation is almost nothing, the genesis is enorm-
ous ; and where, as we rise in the organic scale, there is more
individual growth and development, and consequently a
greater expenditure of the vitality in this direction, the genesis
falls. And further, that inimical factors which in any way
reduce the normal quantum of vitality, not only reduce the
amount expended upon individuation, but also upon genesis,
and the prolificness must consequently fall. We can trace
this ‘‘moving equilibrium’’ between individuation and genesis
in man as well. ‘Therefore we expect to find in the higher

172 Eugene Rollin Corson

types of man, with greater differentiation and a more complex
brain and nervous system, and where there must necessarily
be a greater expenditure towards individuation,—and where
genesis itself is more elaborate,—a lower prolificness. And,
on the contrary, we find, as we might expect, a higher rate of
prolificness among savages than among the Caucasian. But
this holds good of the savage only as he is found in his own
habitat, and under the natural conditions of which he is the
product. Remove him from his natural soil and climate,
change his conditions of life and surroundings, and throw him
into competition with a superior race, and ina civilization
which has been brought about by the growth of that race,—a
civilization of which he is not the product, —and he is placed
in an abnormal condition, and must suffer physically. And
this will show itself in a general deterioration of physique, in
a higher rate of mortality, and in a lowered rate of increase.

We see again in certain organic forms a sort of law of com-
pensation where nature seems to provide for great loss of life
by a greater prolificness, but these two terms stand to each
other as correlatives rather than cause and effect. It is very
evident that there can be no such relationship at all compar-
able in the higher forms of life. Here where inimical factors
arise which render individuation more difficult and more pre-
carious, the expenditure of vitality becomes greater in this
direction, and so much the greater the more complex is the
individuation ; and in like manner the genesis suffers the
more, the more complex its processes are. And thus a race
which is struggling hard to maintain individual life, and
which suffers in addition from an unhealthy living, and from
excesses of all kinds, and whose death rate is high as com-
pared with the more favored race, cannot maintain its normal
rate of increase, but, on the contrary, must show a diminished
prolificness.

And another point worthy of consideration is this: It is not
so much a question of How many offspring ? but How many
matured and perfected individuals? In other words, what is
the ability to maintain life when started? And this is what
I mean by the vital equation. The figures I have given of

The Colored Race 173

the low rate of infant mortality in Japan are interesting as
showing how, in spite of the low birth rate in that country,
the low death rate among infants and young children up to
the fifth year has led to a large increase in the census re-
turns. And how much better this state of affairs is from an
economic standpoint than that of a high rate of genesis with
a high infant mortality. How much greater the loss of
vitality from the general store of the race! In the first in-
stance there is so much the more vitality to be expended upon
individuation, azd that means racial progress; in the second
case, a large amount of the vitality of the race is lost in
blighted and immature individuals, and the general level of
individuation is lowered, axd that means racial decay. ‘The
laws of propogation have been violated in some way, and the
vital equation of the race lowered. And it naturally follows
that the more complex the problem of life becomes, the more
closely these inimical factors are brought to bear, and the more
evident and far-reaching will be the destructive influences
upon the race. And here in the United States, which is be-
coming more and more densely populated with the Caucasian,
where the struggle for existence is becoming fiercer, with a
great increase in material civilization and all the requirements
devolving upon it, all the inimical factors I have enumerated
will bear with redoubled force.

And still another point worthy of consideration is this, that
despite caste and social barriers, there can be, and is, a phy-
siological fusion of the two races. The extent of this fusion
is seen in the mixed element. The exact proportion of this
element to the pure negro we are unfortunately unable to in-
dicate, the attempts made by the last census being quite unsatis-
factory. ‘This element, I am persuaded, is much greater than
is generally believed. I also think that it will increase with
much greater strides in the future as the social barriers to
miscegenation are removed. As Ihave attempted to show,
this element is largely an unstable one, and of a low vital
equation. The process may be likened to a reducing agent,
chemically speaking, which borrows vitality from the pure
race to produce a new compound which is unstable. The

174 Eugene Rollin Corson

process may be represented in a different way, again, where
the dominant race can be likened toa great polyp which, hav-
ing surrounded and ingested a smaller community of cells
than itself, proceeds to appropriate that which is assimilable,
and to throw off that which is foreign and non-assimilable.
This great selective process is evident to-day between the two
races. ‘hus thrown into intimate contact they cannot de-
velop on separate lines, each working out its own racial des-
tiny ; there must be a fusion more or less rapid and a struggle
for supremacy, where the dominant race holds to its racial
traits and its civilization, modified, perhaps, to a certain ex-
tent, by what it has appropriated from the inferior race.

I have thus attempted to show that, according to the
census, the colored race has not increased at the same rate
as the whites, that the colored race is an inferior race, that its
physique has deteriorated, and with a consequent higher
death rate ; that the mixed element has a lower vital equa-
tion, and that all these results are explainable from the teach-
ings of ethnology and biology.

As to the future of the negro in the United States I can see
but one goal, and that is defeat, and by defeat I mean an in-
ability to maintain the race as a race with all its characteris-
tics. With the gradual fusion there will be a larger and
larger mixed class ; the lighter this element becomes the more
the African fades out, and the more the new product ap-
proaches the Caucasian. The term “‘ African ’’ will become
more and more of a misnomer. Even in the few years, com-
paratively speaking, which have gone by, the colored popula-
tion is a quite distinct body from its African ancestors. In
this process of fusion and assimilation there will be a great
loss of life, but there will long be a Caucasianized element,
becoming larger and larger up toa certain point, and I can
believe in a vanishing point, so to speak, where it will be
hard to trace the alien blood. We see it in many individuals
to-day. Its different grades are but as mile-posts on the road
to extinction. All this will require time, and probably cen-
turies will go by before the extinction of the race, as a race,
will be accomplished.

The Colored Race 175

In the mean time I can see no ground for fear of any great
clash between the two races, so much dwelt upon by certain
writers. This is a problem which will solve itself. There
are more serious social and political problems before us to-
day than the poor negro. But of course the care and treat-
ment of this great mass for the present and the near future is
a great problem. ‘To most minds the course to be pursued is
plain enough, namely, to elevate them, Caucasianize them
as far as they will permit it, to treat them as we should treat
the lower classes among our own race, educate them, im-
prove their physical condition where we can, in short, make
useful citizens of them. How this may be best accomplished
involves many questions of government and social science,
with which, of course, I have nothing to do.

The whole question but resolves itself into this, that the
world has reached a point where the Caucasian is supreme,
and all else must give way before him.

SAVANNAH, GEORGIA,
June, 1893.

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a) duh, NAG aca (ihe fy i) BN: ietiaiek
Le, ’ ‘

any anys ni

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UA AC

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se fs ay

THE CORRELATION OF STRUCTURE AND HOST-
RELATION AMONG THE ENCYRTINA.

By LELAND 0. HOWARD.

The student of the parasitic Hymenoptera cannot fail to be
impressed by the uniformity with which parasites of certain
more or less restricted groups are parasitic upon insects of cer-
tain groups also of more or less circumscribed extent. Very
broad and sweeping generalizations in this direction to which
there are, however, many exceptions, may be made. ‘Thus,
while the Lepidoptera are parasitized by many representatives
of all of the four principal families of parasitic Hymenoptera,
those of the subfamily Ichneumoninz may in general be said
to be parasites of Lepidoptera. The species of the braconid
subfamily Euphorine are, in the main, parasites of Coleop-
tera, those of the subfamily Microgasterinze are parasites of
Lepidoptera, those of the proctotrypid subfamily Platygas-
terinze are parasites of Diptera, mainly of Cecidomyiide, and
those of the subfamily Dryininze of the Homoptera of the fami-
lies Membracide, Jassidee, Tettigoniidee and their allies. In-
stances of this kind might be multiplied, but, at the same
time, groups in which much less uniformity exists are also
numerous. :

In the family Chalcidide, to which the subfamily which I
shall particularly discuss belongs, there is the same uniformity
in some groups and the same lack of uniformity in others.
Very few of the subfamilies may be said to possess any great
uniformity throughout their whole extent. The Tetrasti-
chinze, however, appear to be uniformly parasites of other
parasitic Hymenoptera, while the Elachistinze are parasites
(mainly external) of Lepidoptera, and the Torymine are par-
asites of gall-insects, the preference of the latter depending
not so much upon the structure of the host as upon its posses-
sion of the gall-making habit, since they attack cynipid, ceci-
domyiid, trypetid, and even lepidopterous gall-makers.

178 Leland O. Howard

In the majority of the subfamilies, however, there is a much
greater subdivision of the correlation of structure and habit,
frequently descending to genera, and often apparently to
species.

A lengthy series of interesting though occasionally appar-
ently conflicting facts could be gained by the careful study of
the host-relations of the species of any one of these subfamilies,
but in undertaking such a study it is prerequisite that the
group shall have been well classified from morphological de-
tails and that very extensive rearings shall have been made.
These two prerequisites debar us at the present time from any
but initial attempts at generalizations with most of the groups
where the general trend of habit is not at once evident. It is
even too soon to secure the best view of the conditions in the
subfamily which I have chosen, but sufficient facts are avail-
able to render study and arrangement of interest and perhaps
of importance.

The Encyrtinze of Europe have been carefully monographed
by that learned and able entomologist, Dr. G. Mayr, of Vienna,
(Verh. d. K. K. Zool-Bot. Ges. Wien, 1876). Nearly all of
the European forms have passed beneath his analytical eye
and a model systematic paper has resulted. He has also col-
lated and displayed in an instructive table all biologic facts
known concerning the species of that fauna.

Originally drawn to the study of the group through its econ-
omic importance as containing so many parasites of injurious
Coccidz, the writer has, at unfortunately rare intervals, since
1880 studied the structure of the North American forms with
the unrivalled advantages offered by the collection of the U.
S. National Museum. The European species accepted by
Mayr in 1876 numbered 102, distributed in 25 genera. The
North American species contained in the National Museum,
number about 150. ‘Twenty of the 25 European genera have
been found to have representatives in our fauna while repre-
sentatives of 14 new genera have been found. The 150 species
of the Museum collection have all been carefully studied ge-
nerically and have been generically placed, although only about
50 have received specific description and name. ‘This is our

Correlation of Structure and Host-Relation 179

basis for the first of the prerequisites—that of systematic classi-
fication from structure alone.

For the second, knowledge of host-relations, we have
Mayr’s table and the extensive rearings and notes of the Divi-
sion of Entomology of the U. S. Department of Agriculture,
which my chief, Dr. C. V. Riley, permits me to use for this
purpose, as well as his own personal notes made mainly in
Missouri prior to 1876. In all these comprise more than 200
rearings and of the r50speciesin the National Museum collec-
tion, about 120 have been reared and the host-insect identified

with sufficient accuracy for our present purpose.
Let us see then how far uniformity of habit goes in this
group, by taking up one after another of the described genera :

fehopus Forster.—European :—Coccus racemosus.
American :—Pseudococcus aceris, (Ill.) Dactylopius ephedre (Cal.)
FHlolcothorax Mayr.—European :—Lthocolletis 5 spp., Tischeria com-
planella, Nepticula splendidissimella, Hyponomeuta 4 spp., Plusia
moneta.
Aphycus Mayr.—European :—Coccide 9 spp., nearly all Lecaniine.
American :—Lecanium, 9 spp., (Mo., S.C., Ala., Cal., Va., Oreg. Fla.)
Dactylopius, 2 spp., (Cal.) Ceroplastes, 2 spp., (Ariz., N. Mex.)
Kermes I sp., Pulvinaria innumerabilis, (Ia.) Diaspis rose, (N.
J.) Mytilaspis citricola, (Fla.)
Blastothrix Mayr.—European :—Coccide, 9 spp., mainly Lecaniinz.
American :—Vecanium, 4 spp., (N. Y., Cal., Fla.), Pseudococcus
yuccee (Cal.)
Psilophrys Mayr.—European :—Lecanium sp.
Leptomastix Foerst.—American :—Dactylopius destructor, (D. C.)
Copidosoma Ratz.—European :—Agrotis fumosa, Hadena polyodon, Leu-
cania albipicta, Plusia 5 spp., Catocala electa, Geometra, Cidaria
variata, Eupithecia 4 spp., Tortrix sp., Carpocapsa splendora, Hy-
ponomeuta 2 spp., Cerostoma sp., Depressaria 2 spp., Gelechia fa-
vilaticella, Lita alsinella, Tachyptilia populella, Coleophora, 2 spp.
American :—Papilio turnus, (W. Va.) Celzena renigera, Plusia bras-
sicze, (many states.) Aletia xylina, (Ark.) Acronycta sp., (Mo.)
Unknown Noctuid larve, 3 spp., (Colo., Ont., Quebec.) Sericoris
coruscana, (N. H.) Gelechia gallzesolidaginis, (Mo.) G. pseudaca-
ciella, (D. C.) G. gallaeasterella, (N.J.) G.sp. (Ala.) G. viburnella,
(Mo.) G. epigeeella, (Va.) Tinea granella, (D. C.) Bucculatrix
thuiella, (Mo.) Coleophora sp.,(D.C.) Lithocolletis fitchella, (D.
C.) Unknown Tineid larva, (Mo.)

180 Leland O. Howard

Bothriothorax Ratz.—European :—Syrphus larva, Anthomyia cepa-
rum.

American :—Syrphid larva, (Va.) Syrphid larva feeding on Rose
Aphis, (Cal.) About to oviposit on Syrphid larva, (N. Y.)

Chiloneurus Westw.—European :—Coccide, 4 spp., probably all Le-
caniine.

American :—\,ecanium spp., (Ia., Va., D. C,, Wis,, Mo.) Dactylopi-
us destructor, (D. C.) Dactylopius sp., (Cal.) Kermes sp., (Tex.)
Diaspis rosze, (Cal.) Aspidiotus sp., (Cal.) ,

Comys Forst.—European :—Coccide, lo spp., apparently all Lecaniinz.

American :—lecanium, 5 spp., (D. C., Ala., La., Cal.) Pulvinaria
sp., (no locality.) Kermes sp., (N. Y.)

Hlomalotylus Mayr.—European :—Coccinellid larva, Galeruca calmari-
ensis.

American :—Cycloneda sanguinea, (Fla.) Unknown Coccinellid lar-
vee, (Fla., Ia., N. Y., N. Mex.) Anatis 15-punctata, (Mo.)

Cerchysius Westw.—A merican :—Icerya rose, (Jamaica, B. W. I.)

Isodromus Howard.—A merican :—Chrysopa cocoons, (Cal., N. C., Mo.,
Dr. Tex. Hla. Nv Mex)

Pentacnemus Howard.—A merican :—Bucculatrix thuiella, (Mo.)

Tanaostigma Howard.—A merican :—Larva of Tychea, (Cal.)

Rileya Howard.—A merican :—Dactylopius, (Cal.)

Cerapterocerus Westw.—European :—Coccidee, 5 spp.

Habrolepis Foerst.—European :—Coccide, 4 spp.

Phenodiscus Foerst.—European :—Coccide, 6 spp.

Ericydnus Walk.—European :—VLecanium vitis.

Beocharis Mayr.—European :—Undetermined Coccid.

Dinocarsis Foerst.—A merican:—Thyridopteryx ephemerzeformis, (Fla. )

Encyrtus Dalm.—Huropean :—Eumenes coarctata, Ceuthorrhynchus
assimilis, eggs of Bombyx neustria, eggs of Lasiocampa pini, eggs
of Notodonta, unknown Lepidopterous eggs, larva of Eupithecia 2
spp., Syrphus larva, Cecidomyiid galls, 2 spp., Aphis sp., Coccide,
15 spp.

American :—Cynipid gall on Oak, (Ala.) Nest of Ceratina dupla,
(N. Y.) Ichneumonized cocoon of Artace punctistriga, (Fla.) Eggs
of Buprestid, (Cal.) Eggs of Clisiocampa sp., (?) Larva of Desmia
maculalis, (Mo.) Eupithecia miserulata,(Me.) Bucculatrix pomi-
foliella, (N. Y.) Bucculatrix sp., (D. C.) Laverna sp., (Mo.)
Mesograpta polita, (Fla.) Cecidomyia s.-siliqua, (N. H.) C.s.-
batatas, (Mo.) Eggs Anasatristis, (Fla.) Eggs Prionidus cristatus,
(Tex.) Heteropterous eggs on Pine, (Cal.) Trioza diospyros, (Fla. )
T. magnoliz, (Fla.) Pachypsylla celtidis-gemma, (Mass.) Psyllid
on Arbutus, (Cal.) Psyllid on Amelanchier, (D. C.) Aphis brassicze,
(Fla.) Megoura solani, (Fla.) Glyphina eragrostidis, (Ind.)

Correlation of Structure and Host-Relation 181

Pemphigus spirothecee, (?) Siphonophora avenz, (Ind.) Aphis
pruni, (Ia.) Lecanium, 3 spp., (Cal., Fla., Mo., Neb.) Pulvinaria
innumerabilis, (Mo.) Dactylopius destructor, (Fla.) Kermes,
3 spp., (Cal., N. Y., Mo.) Aspidiotus corticalis, (Fla.) Diaspis
rosz, (D. C., Mo., Cal.)

From this condensed statement certain interesting facts
plainly appear. Rhopus, Holcothorax, Aphycus, Blastothrix,
Psilophrys, Leptomastix, Chiloneurus, Comys, Cerchysius,
Rileya, Cerapterocerus, Habrolepis, Phzenodiscus, Ericydnus
and Beeocharis, or 15 out of the 23 genera of which we know
the habits, are parasitic upon bark lice exclusively. Copido-
soma, Pentacnemus and Dinocarsis are parasitic exclusively
upon lepidopterous larvee. Bothriothorax is parasitic upon
dipterous larve only. Homalotylus is parasitic exclusively
upon coleopterous larvee of the families Coccinellidae and
Chrysomelidz. Isodromus is parasitic exclusively upon
Chrysopa larvee, issuing from their cocoons. Tanaostigma is
parasitic upon the larvee of seed-inhabiting weevils.

Thus far there has been absolute uniformity in host relation
within generic bounds in so far that the host insects of each
particular genus are closely related and of the same general
type. There is one genus remaining, however, which is a
biological complex and, from the uniformity which has existed
among other members of the group, the natural inference that
it is also a morphological complex would be justified. Close
study of the classificatory characters bears out this assertion.
Encyrtus is oue of those unwieldy genera of varying limit,
found in nearly every large family of insects, in which many
species have been lumped, frequently for insufficient reasons,
and really for want of a better place to put them. Up toa
certain stage in the classification of the group, authors have
not felt justified in separating the species generically, since
their characters have not seemed as important as those which
have been considered of generic value, while the subgenus is
an element of convenience or confusion, according as you may
view it, which has not as yet been adopted to any extent in
entomology. Encyrtus is such a genus. Coming at the end
of a synoptic table, by a process of elimination the refuse has

182 Leland O. Howard

been left for this unfortunate group. Its definition lacks that
trenchant clearness characteristic of Mayr’s other generic
characterizations, and what are really diverse types to-day
bear this generic name.

In glancing through the host insects which species of
Encyrtus affect we find in Europe a wasp larva, a beetle larva,
the eggs of noctuid and bombycid moths, the larva of a
micro-lepidopter, the larva of a syrphus fly, dipterous galls,
plant lice and bark lice. We have thus 8 types of host insects.
In America we have also a wasp larva as well as two other
hymenopterous hosts, viz. : an Ichneumon and a cynipid gall.
We have also the eggs of a bombycid moth and of a beetle,
the larva of a micro-lepidopter, larva of a syrphus fly, dipter-
ous gall-makers, plant lice and bark lice, and two new ele-
ments in addition to the beetle eggs and the hymenopterous
insects mentioned above, viz., heteropterous eggs and Psyllide.
We have then 12 quite distinct types of hosts, all told, 8 of
them occurring in Europe and all in America.* With this
view of the biology of the genus it at once becomes important
to make a closer study of the morphological aspect of the in-
dividual forms than has yet been done. One would naturally
expect to find an assemblage of characters grouping together
those species which prey upon a common type of host, and,
such characters being found, shall we not be justified in giv-
ing them greater classificatory weight than parallel separating
characters which are not correlated with important, not to say
vital, biologic facts ?

No attempt has hitherto been made in this direction. To
test provisionally the aptness of the idea, a brief survey of
the synoptic table of European species shows that while no
attempt has been professedly made to form natural groups,
yet the characters hit upon to conveniently analyse the species
have brought into immediate juxtaposition the species para-
sitic upon lepidopterous eggs; those parasitic upon dipterous
larvee are brought into close connection ; the bark-louse para-

*Should the species of Encyrtus described by Girard as coming from
a Psyllid gall prove to belong to this genus, Europe will have represen-
tatives of 9 of the types.

Correlation of Structure and Host-Relation 183

sites are lumped, and those parasitic upon lepidopterous larvze
occur together, although separated widely from those para-
sitic upon the eggs of the same order.

And now as to the results of an examination of our Ameri-
can forms:

It will not be necessary in this paper to go into detail as to
the structural peculiarities which have been found upon this
examination. ‘They will be summarized elsewhere in connec-
tion with the descriptions of the new genera necessitated by
this investigation. The conclusions arrived at, however, are
as follows :

Among the species parasitic upon Coccidz we find three
distinct types two of which will form new genera. The most
abundant is parasitic upon Lecaniinze and Coccinz, the sec-
ond upon Diaspinze while a third and isolated type is reared
from a lecaniine—Pulvinaria innumerabilis.

The species parasitic upon Aphididz possess a common
facies and form an independent type in the group distinguished
by well-marked structural characters.

Among those parasitic upon Psyllidz we find an interesting
state of affairs. Those reared from gall-making Psyllidz be-
long to the same type as that reared from a gall-making ceci-
domyiid, while those parasitic upon nearly free-living Psyllidz
belong to two types, distinct from each other and from the
first, and dividing upon geographical lines, the one being east
coast and the other west coast.

The parasites of the free-living dipterous larvz belong to a
common type distinct from the others, while that reared from
the dipterous gall-maker agrees in facies and in main struc-
tural characters with those just mentioned from psyllid galls.

The species reared from a cynipid gall, however, forms still
another type and the most distinctly marked one of the whole
series.

The species reared from lepidopterous larve belong to a
common type, distinct from the rest, but most closely resem-
bling the forms reared from free-living dipterous larve.

Those reared from heteropterous eggs and those from lepi-
dopterous eggs belong to a common type and while separable

184 Leland O. Howard

from each other by certain structural characters, these seem
unimportant compared with those which we have been using,
and for the present, at least, these parasites must remain con-
generic.

The single species reared from a beetle egg forms an isolated
type in the group as does also the single species reared from
an ichneumon cocoon.

That reared from Ceratina is a single specimen lacking an-
tennze and these organs furnish the principal characters of the
European E. varicornis which we should expect it to resemble
from the fact that the latter was reared from Eumenes. ‘The
other structural characters given are not especially distinctive,
but it is worthy of note that they agree with those of our
Ceratina parasite.

We have then, in summing up, fourteen distinct types of
the genus Encyrtus to the discovery and exact definition of
which we have been led by a knowledge of the host-relations
of the species. Upon thirteen of these types new genera will
be founded, leaving to the fourteenth the old generic name.
Those parasitic upon Aphidide, Cynipide, lepidopterous
larvee, coleopterous eggs, ichneumonid cocoon and bee larva
form each a distinct type. Those parasitic upon Coccidze
form three, two of which are well differentiated biologically
by the character of the host-insects within the family. Those
parasitic upon Psyllidz and Diptera form three and two re-
spectively, one of which is possessed by both in common, the
gall-making habit of the host producing the similarity in the
parasite, as is common in other parasitic groups. And these
parasitic upon heteropterous and lepidopterous eggs form a
single type, as is also occasionally the case with other parasitic
groups.

This little paper then tends to show: (1) Another exempli-
fication of the axiom that structure is dependent upon habit ;
(2) that while the true classification depends entirely upon
structural detail, we may gain ideas as to the relative value of
characters by a knowledge of vital habits; and (3) that as
soon as sufficient records accumulate it will be important to
examine the classificatory bearings of the group-habits, par-

Correlation of Structure and Host-Relation 185

ticularly of the host-relations, with other groups of parasitic
Hymenoptera.

I am perfectly aware that after all I have touched only upon
one side of this important subject. The other side is the
structural differentiation of forms whose host-relations are
identical. Parasites of several genera and even families are
parasitic upon the same host-type and even upon the same in-
dividual. Comparatively widely different factors must here
influence the structure and a wide field of investigation is thus
opened.

WASHINGTON, D. C.,
August 9, 1893.

THE FERMENTATION TUBE WITH SPECIAL REF-
ERENCE TO ANAEROBIOSIS AND GAS PRODUC-
TION AMONG BACTERIA.

By THEOBALD SMITH.

In the study of the microscopic forms known as bacteria we
have what might be fitly called the focal point of the various
branches of biological science. Though their investigation
may require careful morphological researches yet the unmis-
takable monotony of form, combined with aconsiderable vari-
ation of physiological activity, has compelled the bacteriologist
to pay much attention to means by which such physiological
variations may be more or less accurately registered in order
that they may serve asa supplementary basis for classifica-
tion. Again, with unicellular organisms the manifestations
of cell activity become the most important phenomena for
study. These manifestations bring together the fields of
physiology and chemistry and make bacteriology in one sense
a branch of physiological chemistry.

In dealing with bacteria and the results of their activity, one
fact strongly impresses us and that is the necessity of knowing
precisely and unmistakably the organism before us. No mat-
ter how profound the physiological and chemical studies of
bacterial life, unless they are linked to an organism readily
identifiable they have failed to assert their full value. In all
the investigations of bacteria in their relation to the fermenta-
tion industries, to the dairy, to the soil, and to human and
animal diseases now going on, the element of fundamental im-
portance is the organism itself. About this all functions are
grouped, to this every question finally reverts. The necessity
for more accurate means of recognizing species and varieties
has, however, not generally been felt and the methods of diag-
nosis have not kept pace with progress in the more practical

188 Theobald Smith

fields of microbiology. The species studied some years ago
are assuming a more and more hazy outline and questions are
constantly arising concerning the possible identity of old with
new forms. ‘This condition is largely unavoidable in a young
and rapidly growing department of science and is in part due
to the fact that investigators are too prone to attack new prob-
lems before the more orderly work concerning the old ones has
been completed. For this state of affairs they are hardly to
be blamed, for the profound relations of bacteria to other life
on our globe has given the study of them a practical bias
without which the resources now employed in investigations
could never have been wrested from the utilitarianism of our
present social organization.

It is due to considerations such as these that this article is
presented as a contribution to the methods by which bacteria
may be more definitely recognized. A complete differentia-
tion is possible only through a complete knowledge of the bi-
ology of any given organism. ‘This knowledge is only grad-
ually acquired and more or less temporary expedients must
be resorted to to fix the hosts of microdrganisms shading into
one another by almost intangible gradations of form and func-
tion. Among these expedients the fermentation tube occupies
an important place in the differentiation of the more sapro-
phytic forms and in giving usa fairly good conception of their
powers of fermentation. I can do no better therefore in com-
memoration of the present occasion than to offer the observa-
tions which I have made with it during the past four years, as
a connected whole to the biologist.

The fermentation tube appears to be an apparatus of considerable
antiquity. The bent tube closed at one end has been used by chemists
in storing small quantities of gas for qualitative analysis. I have been
unable to determine who was the first to apply it to fermentation pro-
cesses. In Detmer’s Aflanzenphysiologisches Practicum I find it figured
as Kiuhne’sches Gahrungsgefiss. More recently it has been adapted
by Einhorn! for the quantitative determination of sugar in urine and by
Doremus for the quantitative determination of urea in the same fluid.
In 1889 I conceived the idea of using this tube as an ordinary culture
tube in order to determine something more definite concerning the pro-
duction of gases by bacteria without resorting to the complex manipula-
tions of the chemist”. The form of the tube used in the following study

The Fermentation Tube 189

is given half size in the plate (fig. 1). It is essentially a tube bent
at an acute angle, closed at one end and enlarged at the other into
a bulb. At the angle the tube is more or lessconstricted. To it aglass
foot is attached so that the tube may stand upright. For the sake of
uniformity, the closed portion of the tube will be denominated ‘closed
branch,’’ the open portion, ‘‘the bulb,’ the intermediate narrow, bent
portion the ‘‘connecting tube.”’

In the construction of this simple bit of apparatus several points must
be borne in mind. The bulb should be large enough to receive all the
fluid contained in the closed branch, for in some kinds of fermentation,
the gas production drives out all the fluid from the closed branch. The
cotton-wool plug must not be moistened under such circumstances
otherwise the purity of the culture is imperilled. If the bulb is suffici-
ently large this difficulty will not arise. The connecting tube should
not be toosmall, for then the filling and emptying of the closed branch
becomes very tedious. Nor should it be too large, otherwise the anaé-
robic properties of the fluid in the closed branch, to be discussed farther
on, may be lesseffective. Lastly theangle formed by the two branches
of the tube must not be too acute otherwise the tube must be tilted so
much during the transferrence of the fluid from the bulb to the closed
branch that there is danger of its moistening the plug or even running
out of the bulb. Since the closed branch is not accessible to cleansing
with a brush it is advisable to fill the tube after use with the ordinary
cleaning mixture (bichromate of potash and sulphuric acid) and allow it
to stand undisturbed for some days.

The filling of the tube with culture fluid does not give rise to any
difficulty. The fluid is poured into the bulb until this is about half full.
The tube is then tilted until the closed branch is nearly horizontal so
that the air may bubble up through the connecting tube and permit the
fluid to enter the closed branch. When this has been comipletely filled,
enough fluid should be added to cover the lowest expanding portion of
the bulb. If the tubes are likely to remain unused fora month or
longer it is best to add fluid until the bulb is half full to allow for evap-
oration.

The sterilization requires afew suggestions. This is best done ina
steamer like the ‘Arnold’ forthe tubes can be placed directly on the
perforated plate in the bottom of the steam chamber. If a steamer is
not at hand, an ordinary tin or granite-ware pail having a tight cover
may be used. Enough water is poured in to form a shallow layer. To
prevent the upsetting of the tubes by the ebullition I have been in the
habit of placing them, three or four together, into perforated cups
which are placed directly on the bottom of the pail. Steaming or boil-
ing on three consecutive days is sufficient for complete sterilization.
During the boiling the tension of the aqueous vapor in the closed branch

190 Theobald Smith

forces much of the fiuid into the bulb. As soon as the lid is removed
the fluid returns to its former place in the closed branch with the excep-
tion of asmall space at the top which is occupied by air originally dis-
solved in the liquid and driven out by the boiling. This air bubble
should be tilted ont. After the second boiling some air may still be
present. If this be tilted out the fluid will be found entirely free from
air after the third or last boiling.

PHENOMENA OF ANAEROBIOSIS AND REDUCTION.

For the cultivation of bacteria the fermentation tube con-
sists of two quite distinct portions sharply demarcated at the
place indicated by the line xy in fig. 1. The bulb contains
fluid in direct communication with the air while the fluid in
the closed branch is almost entirely shut off from any such
communication. Moreover, during the process of sterilization,
the fluid in the latter has been entirely freed of air, as de-
scribed above. ‘This oxygen-free condition of the fluid is very
clearly demonstrated by the following simple experiment :

If to peptone bouillon be added a few drops of a concen-
trated aqueous solution of litmus, methylene blue or indigo-
carmine, and fermentation tubes be filled with this colored
fluid and sterilized, the fluid will be decolorized during the
boiling by reducing processes due to the organic substances in
the peptone bouillon*. In the open bulb the presence of air
very speedily causes a return of the color. In fact it may not
completely disappear at any time. If the tubes containing
the colorless, reduced litmus or methylene blue be allowed to
stand ina place sheltered from sudden changes of tempera-
ture, the fluid in the closed branch remains free from color
(with perhaps a faint indication of color near the connecting
tube) until the time arrives when the fluid in the bulb has
evaporated and a bubble of air escapes into the closed branch. f

*T at first conceived the reducing action due to the glucose only, but
the same process went on in peptone bouillon free from glucose. It is
not due to simple boiling, however, for litmus or other coloring matter
contained in simple bouillon or in water with or without a little Na,CO,
remains unchanged in the sterilization. It is thus dependent on the
presence of glucose or peptone.

+ This occurrence is like the escape of air into the reservoir of a stu-
dent lamp which brings about the continuous feeding of the wick with

oil.

The Fermentation Tube Ig!

Then the color begins to return and shows itself first at the
very top of the closed branch beneath the air bubble.
Thence it spreads slowly through the liquid as the evapora-
tion continues to bring more air into the closed branch.
These facts make it clear why the connecting tube should be
as narrow as is compatible with the ready filling and emptying
of the closed branch, for the smaller the calibre of this tube
the less the interchange of fluid between open and closed
portion. A

Let us now consider the effect which this oxygen-free state
of the culture fluid has upon the multiplication of bacteria.
There is first of all a class of bacteria which multiply remark-
ably well in the bulb and the connecting tube but the fluid of
the closed branch is shunned by them so thoroughly that it
remains perfectly clear and limpid. The line of demarcation
between the turbid, teeming liquid of the bulb and connect-
ing tube, and that of the closed branch is sharply drawn.
Evidently this class of bacteria are not only unable to multi-
ply in fluids deprived of oxygen but they seem to avoid them
as if influenced by a negative chemotaxis in spite of the
power of motion which many of these forms possess. This
limitation of growth has been observed in case of the same
species from widely different sources as to time and place and
hence stands for a constant character of the species. To this
class belong many spore-bearing bacilli found in nature
(Bacillus subtilis) and other forms (Bacillus fluorescens lique-
faciens), and it corresponds to the class long known as the
obligatory aérobic bacteria. The old test for this class, intro-
duced by R. Koch, was an incapacity to multiply under a mica
plate laid upon the gelatine layer in which the bacteria were
supposed to be multiplying.

A second group of bacteria multiply not only in the open
bulb but also in the closed branch. The fluid becomes uni-
formly clouded but the growth soon subsides for there is in
most cases a decided preference for the open bulb, varying
slightly with different species. In this the density of the
growth always corresponds to that of cultures in ordinary
cotton-plugged test tubes containing the same fluid. ‘To this

192 Theobald Smith

class belong the greater number of the gas-producing bacteria
to be considered farther on. It corresponds to the facultative
anaérobic group, that is, those forms which are capable of
multiplying to a certain extent in media free from oxygen al-
though they flourish best in the presence of this gas.

There is lastly a third group of bacteria, of which I have
examined only a small number in the course of the past four
or five years, which do not multiply in the open bulb but seek
the closed branch. ‘These are the strictly anaerobic forms
which require a medium devoid of oxygen. Many of them
are gas-producing.

The fermentation tube thus informs us at once to which of
these three groups of bacteria any given species belongs.
This determination is especially valuable with the facultative
anaérobic and the aérobic species. The anaérobic nature of
any given form is usually manifested beforehand by its refusal
to multiply inthe ordinary culture tubes. It is needless for
me to go over the various methods and devices which have
been and are still employed in defining the aérobic or anae-
robic character of bacteria. They are given in part in current
text books. ‘The simplicity of the test in the fermentation
tube will at once appeal to all who have striven to produce a
vacuum or substitute for the air an atmosphere of hydrogen.

The possibility of cultivating aérobic and anaérobic bacteria
in the same kind of tube makes more simple certain bacterio-
logical work carried on hitherto under considerable difficulty
and with but partial success. In the determination, both
quantitative and qualitative, of bacteria in the soil or the in-
testinal tract for instance, the aérobes and anaérobes had to
be dealt with separately. In the solution of such problems
the fermentation tube may do good service if the method of
dilution be employed. Since this tube shows no discrimina-
tion between these two physiological groups of bacteria all
would have an opportunity to develop. I am well aware of
the difficulties inherent in the method of dilution,—the diffi-
culty of gauging the dilution beforehand, the large number
of tubes required, the care to be taken in the manipulation of
the fermentation tubes, their size and cost—but these diffi-

The Fermentation Tube 193

culties are not those which threaten the success of the work
and they count for little in important special investigations.

The Reducing Action of Bacteria.—It has been known for
some years that certain bacteria have the power of abstracting
oxygen from compounds which hold it very loosely. It has
been customary among bacteriologists to demonstrate this de-
oxidizing or reducing activity by adding certain substances to
the culture fluid which are colored in the oxidized state but
which lose their color in the reduced state. Among the sub-
stances used are those mentioned above in the discussion of
the anaérobic properties of the tube, and the action of bacteria
correspond precisely to the action of heat in the presence of
glucose or peptone as has been already described. It is not
my intention to discuss this interesting phenomenon of reduc-
tion among bacteria excepting to call attention to the fermen-
tation tube in bringing it out.

It will be remembered that when methylene blue, or indigo
carmine or litmus be added to peptone bouillon with or with-
out glucose so that the fluid becomes distinctly colored, and
the tubes steamed, the fluid in the closed branch becomes de-
colorized. If bubbles of air be tilted into the closed branch
and out again repeatedly, the color returns. Such tubes in-
oculated with any bacteria which are capable of growing in
the closed branch, if only toa slight degree, become within
24 hours completely decolorized, with the exception of a
shallow layer of fluid in the bulb. In the closed branch, for
reasons already given, the fluid remains indefinitely decolor-
ized. Inthe bulb the color returns when for any cause the
growth ceases and subsides. It is interestiug to note that in
an ordinary bouillon culture of B. colz, the phenomena of re-
duction and oxidation could be witnessed for 15 days at the
end of which period the culture was rejected. The methylene
blue would lose its color within half an hour after it had been
re-oxidized by allowing air to bubble up into the closed
branch. If asmall quantity of air was allowed to remain in
the closed branch, a stratum of blue fluid would remain at the
top of the fluid column near the air for some days, then dis-
appear completely, thereby indicating the complete consump-

194 Theobald Smith

tion of the oxygen admitted to the confined space, by the
vital activity of the bacteria. Again in glucose bouillon in-
oculated with hog cholera bacilli, the complete paralysis of
the bacteria after a certain stage in the fermentation is very
clearly demonstrated by a permanent return of the color of
the fluid in the bulb. The contrast between the deep blue
color in the latter and the yellowish hue of the decolorized
fluid of the closed branch is very striking.

THE PRODUCTION OF GAS BY BACTERIA.

Attention has been called to the formation of gas by bacteria
by a number of writers in the past. Thus Escherich® in 1885
demonstrated the fact that B. coli and B. lactis aérogenes, both
bacteria of the intestinal tract described by him for the first
time, produce gas in solutions of glucose and lactose. In
1886, Arloing* called attention to the same subject. The
property of gas production had been long associated with the
pathogenic bacillus of ‘‘ black quarter’’ in cattle (Rauschbrand,
charbon symptomatique) which produces gas in the tissues of
the affected part. Similarly the anaerobic bacilli of tetanus
and of malignant cedema are known as gas producers. Among
these anaérobes the formation of gas was demonstrated by
distributing the bacteria in deep layers of liquid agar contain-
ing glucose and congealing the agar at once. ‘The formation
of numerous gas bubbles throughout the agar and the break-
ing up of the jelly by large quantities of gas is described and
pictured and is now a common sight in bacteriological labora-
tories. A large number of bacteria belonging mainly to the
group of facultative anaérobes, are now known as gas
producers. Nevertheless the production of gas by bacteria
has not thus far been taken as a serious matter by bacteriolo-
gists in the differentiation and fixation of species and varieties.
Many have of late years been in the habit of recording the
presence or absence of gas in cultures, but by methods likely
to mislead. Since the gas test has proved the only final
means ot differentiating two important species, B. colz commu-
nis and B. typhosus, much more attention has been paid to
this function but the methods have not materially improved.

The Fermentation Tube 195

In spite of the fact that I called attention to this matter three
years ago’ by describing a procedure for determining the pro-
duction of gas as simple asthe ordinary cultivation of bacteria,
this procedure has not been generally adopted largely because
the fermentation tube itself seems to be looked upon as some-
thing beyond the range of the ordinary bacteriological outfit.

In referring to gas formation writers have been in the habit
of calling attention to the gas bubbles which make their ap-
pearance under certain conditions in stick (S¢ch-) cultures in
gelatin and agar as well as in inclined or ‘‘slant’’ cultures of
agar if there is condensation water present. These bubbles
appear in the depths of the gelatin, one or more days after
inoculation, as flat, lenticular spaces cleaving the jelly in one
or more directions. In agar stick cultures, kept at 37° C.
they appear frequently within 24 hours after inoculation with-
in the depths of the agar jelly. In slant cultures they are
usually found between the agar and the sides of the tube, im-
prisoned there by the condensation water which fills the gap
between the slightly retracted agar and the glass. These bub-
bles depend for their presence on twothings: 1, The capacity
of the particular species for fermenting glucose with the pro-
duction of gas; and, 2, The presence of glucose in the meat
used in the preparation of the nutrient gelatin or agar. As
I shall point out farther on the meat infusion is in some cases
entirely free from such fermenting substance and if accidently
used the bubbles will not appear. This test is therefore unre-
liable. A much better method and one which should not be
neglected if the fermentation tube is not at handis to adda
definite quantity of glucose (or some other carbohydrate) to
the gelatin or agar. Gas bubbles will invariably appear if
the species is capable of producing gas at all. So far as my
observations have gone they show that all gas production is
linked to the presence of glucose or some other carbohydrate
in the culture medium. Before giving illustrations of this
process among different bacteria a few remarks on the mani-
pulation of the fermentation tube are in order.

The fluid used in all cases, with exceptions to be mentioned,
was peptone bouillon containing either glucose, lactose or

196 Theobald Smith

saccharose. ‘The bouillon was prepared by digesting fresh
beef in water at 60° C. for several hours then filtering and ad-
ding \% per cent. peptone, % per cent. sodium chloride and
about 3cc. of a normal solution of sodium carbonate for every
hundred cc. of the fluid. This suffices to make it feebly alka-
line. ‘To this peptone bouillon 2 per cent. of one or the other
of the three sugars mentioned was added and the resulting
fluid sterilized in the fermentation tubes.

These are kept, after inoculation, in the thermostat at 37° C.
A mark made on the sides of the closed branch at the end of
every 24 hours with a glass pencil furnishes an approximate
record of the rate of gas production. Unless this is done it is
impossible to know precisely when the formation of gas is at
an end and also whether or not the volume of gas has been
diminished by absorption. It is best to wait 4 or 5 days after
the production has ceased before making a final examination.
This is done by noting the condition of the growth, the re-
action of the fluid in the bulb* and the maximum quantity of
gas produced. ‘This is most easily done by laying directly on
the tube a glass millimeter rule and noting the tube length
occupied by gas. The entire length of the closed branch is
also noted, making due allowance for the upper convex ex-
tremity and the lower constriction. This mode of measure-
ment is sufficient since only comparative values are desired.
For the same reason all barometic and thermometric correc-
tions are omitted in these approximate estimations.

The examination of the gas produced was limited to the de-
termination of the quantity of carbon dioxide and of the ex-
plosive character of the gas remaining after the absorption of
CO, by sodium hydrate. These facts are determined by the
following simple manipulations :

The bulb is completely filled with a 2 per cent. solution of
NaHO and closed tightly with the thumb. The fluid is
shaken thoroughly with the gas and allowed to flow back and
forth, from bulb to closed branch and the reverse several times

*The reaction was noted by placing a drop of the fluid on delicate
litmus paper. The cultures were occasionally boiled to drive off any
CO,. In no case did the reaction with the litmus paper change.

The Fermentation Tube 197

to insure intimate contact of the CO, with the alkali. Lastly,
before removing the thumb, all the gas ts allowed to collect in the
closed branch so that none may escape when the thumb is re-
moved. If CO, was present, a partial vacuum in the closed
branch causes the fluid to rise suddenly when the thumb is
removed. After allowing the layer of foam to subside some-
what, the glass scale is again applied to the closed branch and
the amount of CO, absorbed may thus be measured. In all
cultures of this character thus far examined the gas remaining
was explosive in character and probably hydrogen. At any
rate wherever hydrogen is referred to hereafter, it simply
signifies an explosive gas whose analysis must be left to the
chemist. The explosive character of this residue is easily de-
monstrated as follows :—The cotton plug is replaced and the
gas in the closed branch allowed to flow into the bulb and
mix with the air there present. The plug is then removed
anda lighted match inserted into the mouth of the bulb. ‘The
intensity of the explosion varies with the quantity of air pres-
ent in the bulb.

One difficulty with the culture fluid employed needs to be
mentioned at the outset. Itis the presence of a small, but
variable amount of glucose in the beef or other meat employed.
When only glucose is used the difficulty disappears, but when
other sugars are used we are at a loss to know how much of
the gas to ascribe to the glucose originally present in the beef
infusion or even to know whether the other sugars added are
at all attacked by the bacteria. Recently I tested beef broth
as it was prepared from time to time in the laboratory by in-
oculating fermentation. tubes filled with it with a variety of
§as-producing bacteria. In the following table the total
amount of gas is calculated in percentages of the total volume
of the closed branch which is about 20cem. ‘The amount of
CO, absorbed by potash is given in percentages of the total
volume of gas. The gas remaining is explosive.

Theobald Smith

198

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The Fermentation Tube 199

This table shows that of ten samples of beef broth two
were manifestly free from glucose. Hence the advice of Dun-
bar® to use simply beef infusion (Flezschwasser) to test the
gas producing power of bacteria would lead to conflicting re-
sults unless glucose were added. That the sugar contained
in muscular tissue is glucose as affirmed by physiologists
seems to be borne out by the fact that it is attacked by bacteria
which do not ferment lactose or saccharose.

In order to eliminate the source of error introduced by the
muscle sugar I tried a solution of salts reccommended by
Fermi’ and of the following composition :

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In this solution the bacteria experimented with failed to
multiply when peptone was added and the glycerin omitted.
Whien both were present the fluid in the open bulb became
fairly turbid but that in the closed branch remained practically
free from any growth. Evidently the glycerin could serve as
food only in presence of oxygen. When glucose was added
gas appeared, but much more slowly and in much smaller
quantity than in peptone bouillon with glucose. A compari-
son of results obtained with this artificial solution and pep-
tone bouillon was not possible and further trials with it were
abandoned.

It next occurred to me that the sugar in bouillon might be
removed by allowing some gas-producing bacteria to multiply
in the latter fora time. The bouillon might then be resteril-
ized after a certain quantity of some sugar had been added
and the fluid reinocculated with the species to be studied.
This procedure was found successful so far as gas production
is concerned, but it went on more slowly and apparently in a
somewhat different way. Hence this method was given up.

Dunham’s solution (1 per cent. peptone and % per cent.

200 Theobald Smith

sodium chloride in water) was alsotried. Bacteria multiplied
so feebly in it, however, that it also was abandoned.

The method finally settled on was to test each quantity of
bouillon prepared in the laboratory. If any failed to give
rise to gas in the fermentation tube it was set aside to be used
exclusively with these tubes. Unfortunately most of the gas-
production recorded in the tables following, took place in
bouillon containing traces of glucose since the work could not
be delayed. The difficulty has been partly overcome by keep-
ing a record of the quantity of gas formed in the same bouil-
lon to which no sugar was added.

In searching through the literature of this subject I find that
the presence of glucose in bouillon has likewise been noted by
Peré’ and by Pane* in its bearing on the products of bacteria
fermentation. ‘The former considered it mainly in its relation
to the initial acidity of cultures, a relation, to which I had al-
ready called attention in 1890°. Pane sought to determine the
gas produced in peptone bouillon quantitatively by noting the
number and the size of the gas bubbles in bouillon-agar
when B. coli communis was mixed with fluid agar and this
rapidly hardened by cooling. He likewise determined the
amount of acid produced by the fermentation of this carbo-
hydrate.

TYPES OF GAS PRODUCTION.

In my experience with the cultivation of bacteria in the fer-
mentation tube a variety of hitherto unnoticed details have
come to light. In arranging and classifying these I find more
or less difficulty. It seemed perhaps the simplest plan to de-
scribe the gas production of a very common and much dis-
cussed species—Bacillus coli communis—and then to refer
briefly to those species which belong to the same general
group. ‘The observations of others so far as they bear on the
subject before us will be reviewed in a succeeding chapter.

B. coli communis.—It is not my intention to enter into de-
tail concerning the characters of this somewhat notorious in-
testinal species. At present its main differential characters
are accepted to be 1, motility ; 2, prompt coagulation of milk;
and, 3, gas production in nutrient media containing lactose.

The Fermentation Tube 201

As regards motility it is interesting to note thatit is more
easily overlooked in bouillon cultures than when very recent
colonies on gelatin or agar are examined in the hanging drop.
There is moreover a considerable variation among cultures
from different sources as to this property of motility. ‘There
are to be found all gradations from cultures in which a motile
form may be seen only after prolonged searching, to those in
which almost all individuals are in motion. As to the coagu-
lation of milk there is likewise some variation in this function.
Some years ago I isolated an unquestionable colon bacillus
from the feces of an infant, which failed to produce coagula-
tion of milk even after several weeks’ sojourn in the ther-
mostat. ‘The same may be said ofsome cultures from animals.
These facts show that the colon bacillus is by no means a well
characterized species and the question arises how shall the
various races be classified? The same thoughts have been ex-
pressed by other writers especially by Gilbert and Leon'®. I
believe that the properties of these races as manifested in the
fermentation tube will serve as the best basis for a classifica-
tion.

If we take for our culture a bacillus isolated from human
feces and manifesting all the characters usually ascribed to 2.
coli communis we shall observe the following phenomena in
the fermentation tube at 37° C.

In glucose bouillon within twenty-four hours the entire
fluid has become clouded and a certain quantity of gas has ac-
cumulated in the closed branch. At the end of the second
day more gas has formed. At the end ofthe third day a trifle
more is present. After this very little if any is set free. The
cloudiness promptly subsides and all growth is apparently at
anend. The fluid in the bulb will be found markedly acid.
This acidity is undoubtedly the cause of the sudden cessation
of activity, for if it be promptly neutralized with a sterile so-
lution ofsome alkali the fermentation starts again. It should
be stated that in these observations no ‘‘ acid-binding ’’ sub-
stance, such as CaCO, has been added to the fermenting fluid.
The following table gives in percentages of the tube length of
the closed branch (z. ¢., of the volume of the latter) the
amount of gas formed by &. coli from various sources :

Theobald Smith

202

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(‘azye[q JO7 ‘BSIT) “NO'TIINOG HSOONNID NI S7ummuto? 217079 ‘q—'II

From the foregoing table it will be seen that the largest
amount of gas is produced during the first twenty-four hours

and that the gas itself is made up of CO,, one volume, to an

explosive gas, two volumes.

During the past five years I

have examined a large number of cultures of B. cold which I

Is

1ma

ted ani

lated from the intestinal contents of domestica

180

The Fermentation Tube 203

and in every case this ratio of CO, to H was the same. The
somewhat crude method of measuring the gas, the contrac-
tion of its volume when removed from the thermostat, the
fluctuating temperature of the room, the presence of a layer

_—s
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ct “— — — — — ar -t | ct oO
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faxile —_ oc fou °
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of foam on the surface of the liquid in the closed branch after
the CO, has been absorbed, all these factors enter as slightly
disturbing elements and make the values quoted as only ap-
proximately correct. As might be anticipated from the

lated with B.

inocu

Ik

in in mi

Theobald Smith

f the case

ipitation o

colz, this organism acts upon lactose in the same way as upon

prompt prec

204

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Zon cane sugar in peptone bouillon dif-

col:

The action of 2.

bouillon.

The Fermentation Tube 205

fers with rare exceptions, quite markedly from that upon glu-
cose or lactose. The examination of cultures from different
sources has revealed two distinct varieties, one of which pro-
duces a considerable quantity of gas, the other little or none.
With the former variety the type of gas production varies
somewhat from culture to culture. In general the fluid is
driven out very slowly and the gas production may last sev-
eral weeks. These statements are well illustrated in table IV.

When the gas production goes on very slowly the growth
in the open bulb becomes exceedingly abundant. This is
most probably due to the slow neutralization of the bacterial
alkali, formed in the open bulb, by the acid resulting from
the slow fermentation in the closed branch. ‘The gradual en-
trance of this acid fluid into the bulb acts asa continuous
stimulant to the multiplication of bacteria there. When the
gas production is rapid the fluid in the bulb remains acid and
the growth speedily subsides.

What the true significance of the varying behavior of the
B. colt group towards cane sugar is, can be determined only by
more extended investigations. I venture to suggest however,
that the saccharose fermentation may require in the slow fer-
mentation the presence of an inverting ferment while that of
lactose and glucose goes on without it. . This ferment is ap-
parently no longer formed by some bacteria otherwise not dis-
tinguishable from &. colz. ‘The whole subject is very interest-
ing and seems to indicate either that this species may readily
lose the capacity to act on cane sugar or else that it isina
transition stage towards the more pathogenic species of this
large group of bacteria. The peculiarity of the saccharose
fermentation suggests the thought that the presumable ferment
is formed only in the fluid in contact with oxygen and that it
very slowly diffuses thence into the closed branch. A layer
of sterile oil on the fluid of the bulb would perhaps answer
this question. But I have had no opportunity to try this ex-
pedient. We may summarize the facts concerning the gas-
producing power of B. colz communts briefly as follows :—

In feebly alkaline peptone bouillon containing 2 per cent. of
glucose or lactose, about 50 to 60 per cent. of the closed branch
of the fermentation tube will be occupied by gas in 3 or4

206 Theobald Smith

days and the fluid will be strongly acid. The gasis composed
of about 2 volumes of H and 1 volume of CO,. In bouillon
containing 2 per cent. cane sugar the gas production goes on
in cultures of some varieties. It accumulates more or less
slowly and the ratio of CO, to H varies.*

The Hog-cholera Group of Bacilli.—While forms differing
more or less in physiological and cultural features are thrown
together as L. coli communis, pathogenic forms having much
closer affinities, in fact scarcely any points of difference, are
carefully separated and named. ‘This anomaly is due to the
practical importance of pathogenic species. Of the hog
cholera bacillus itself, an organism of considerable economic
importance as well as of marked pathological interest, I have
examined in the course of the past seven years a number of
cultures from widely different regions of our country. Some
of these possessed minor varietal characters, among which
may be included a considerable variation of pathogenic power.
With a few exceptions the gas-producing phenomena are re-
markably uniform. In case of these exceptions, one of them
a culture now seven and a half years old, the gas production
is somewhat reduced quantitatively. Whether this is an
original peculiarity or a result of prolonged cultivation I am
not prepared to state.

They all possess the power of fermenting glucose in pre-
cisely the same manner as &. coli, but they are incapable of
producing gas in bouillon containing cane sugar and milk
sugar. The absence of any action on milk sugar in this
group is correlative with the absence of any power to coagulate
milk. Even after weeks of sojournin the thermostat and sub-
sequent boiling, milk cultures remain fluid. In this group I
also include astill unnamed bacillus from the genital passages
of a mare, 2B. enteriditis, Gartner“, and B. typhi murium,
Loffler’. These are the only ones which I have carefully ex-
amined. There are probably others, found in different
countries, which belong to this group of pathogenic bacteria.

In the following table are included several distinct physio-
logical varieties of the hog cholera bacillus :—

* The products of the fermentation induced by &. coli have been more
or less exhaustively studied by Baginsky'*, Peré’ and Scruel's.

207

The Fermentation Tube

Vv

.—HocG CHOLERA GROUP OF BACILLI IN GLUCOSE BOUILLON.

Gas present after

SPECIES. is

I day. days.

pr ct. | pr ct.
Dr CHOLCVE SULS. Ts eo; 22 35
« « a Ge ee. 35 51
ss a SS TTS 6 Sent oe 45 58
“ “ “ Tes ee a3 43

(Swine pest. )

Bacillus from mare... . . 12 50
B. typhi murium (Loffler,) . 46
B. enteriditis (Gartner,). . : 49

3

days.

pr ct.
37
56
58
45
58
48
52

4 tke me COR ae REMARKS.*
days.
pr ct. pr ct. PL Cty | prict,

40 37 34 66 | Culture 7% years old.

58 54 oy 63 | Culture 3 years old.

58 52 36 64 | Feebly pathogenic variety ; 4

years old.

45 42 ne 67 | Culture probably 6 years old.

61 55 36.5 | 63.5 | Culture 2 years old.

=e | 501(6th) 35 65 | Culture probably 2 years old.
Bn 6 || SOG 0) Culture probably 5-6 years old.

* The age here indicated refers to the time which has elapsed since the species was obtained from a case of disease,
or since it was discovered.

208 Theobald Smith

I have omitted from the above record four additional cult-
ures of B. cholere suits, three of which are identical with II
and III so far as the quantity of gas produced is concerned ;
the fourth corresponds to IV in this respect. In all varieties
of this sub-group the behavior in glucose bouillon is precisely
the same. ‘There is a rapid evolution of gas on the first and
the second day ceasing promptly on the fourth or fifth. The
growth subsides at the same time. Theculture fluid becomes
strongly acid.

The action of this entire group on saccharose and lactose in
bouillon is negative and hence I omit any tabulation of the
records. Unless the bouillon is free from muscle glucose there
may have accumulated, after one or two weeks, a certain
amount of gas corresponding to that developed in the same
bouillon free from any additions. ‘This may amount to 15 or
20 per cent. of the contents of the closed branch. “A glucose-
free bouillon recently tried remained free from any gas. That
there is, in such tubes, no action on the sugar is proven by
the feeble transitory acid reaction when gasis formed toa
slight extent. This soon changes to an alkaline reaction in
the bulb. When glucose is entirely absent the acid reaction
fails to appear.

B. lactis aérogenes Escherich®, The cultures which I
have tested differ from those of &. colin certain minor but
definite characters. "They were non-motile and provided with
more or less zoogloear or intercellular, but not viscid, sub-
stance often recognizable on the border of the hanging drop as
a distinct capsule. When these bacilli are cultivated on solid
media this capsular substance manifests itself by a regular
spacing between the individual bacilli when these are massed
together. The growth on potato is richer and of a paler yel-
low color than that of B. colc. The surface colonies on gelatin
are usually fleshier than those of the latter and frequently re-
semble little pearly drops. In old bouillon cultures there is
noticeable an even stronger fecal odor than that arising from
similar cultures of B. cold. I give the above characterization
mainly because the species does not seem to be any more stable
in its minor characters than B. colz. The following table gives
the gas production of the only culture thoroughly examined.

209

The Fermentation Tube

The gas

It will be noticed that saccharose is not affected.
formed was traced to muscle glucose in the bouillon.

Kind of
Sugar.

Glucose .

Lactose .

Saccharose

2

days.

g*

Gas present after

VI.—B. lactis aérogenes IN SUGAR BOUILLON.
ee SE ee

3 4 5 6
days. | days. | days. | days.
Ae eee ;
61 63 66 68
47 SO 52

9 II 13 :
12 , 15

Total at
Ook

50 (11th)
58 (7th)
62 (11th)
53 (14th)
13 (11th)
17 (13th)

co,

35

38.5

20

H Remarks.

65 Growth subsided ; acid.

“cc “ ia

61.5 «ce ia “e
61.3 “cc e “e
94 | Growth abundant; alkaline.

80 “c c “

* The second trials with the same kind of sugar were made fully half a year after the first.

10n 1S con-

The fermentation in so far as the gas product

B. coli group.

ire

lar to that of the enti

is precisely simi

cerned

One

We probably have a number of

Theobald Smith

Some years ago” I examined comparatively three slightly dif-
saccharose bouillon.

ferent bacteria obtained from the intestines of the pig.
of these corresponded very closely to the species above de-

scribed but differed from it in producing an abundance of gas

210

in

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} asOIBYIIVS

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“WHAN WIGHT 40 SO TINVE— ‘TIA

The Fermentation Tube 2Tt

varieties which may be grouped under the specific name BZ.
lactis aérogenes and which further fermentation studies may
tend to define and separate. There is furthermore good reason
for regarding this species very closely related to B. colt.

The bacillus of Friedlander*. This species has aroused
considerable attention owing to the supposition prevailing at
one time that it was the cause of pneumonia in man. With
reference to both morphological and cultural characters it
seems to bear the same relation to B. lactis aérogenes which
the hog cholera bacillus bears to B. colz. From the above
table it will be seen that this organism acts vigorously upon
glucose and saccharose but only feebly on lactose.

The persistence of the gas-producing function of this species
is well illustrated by the fact that three years ago the same
culture gave the following result” :

Glucose, total gas 44 pr. ct.; CO, 43.4 pr. ct., H=56.6 pr. ct.
aechiamase nh yl gor yy 6 Se aap fy Fe ef H=59 pr. ct.
Lactose, By ea kee aie Serene nny lee atpr ete

B. edematis maligni. Of anaérobic species only a few have
been cultivated in the fermentation tube. Some of these were
derived from the bodies of animals aid represented those
‘post mortem’’ bacilli quite invariably present some time
after death especially in the carcasses of large animals. ‘These
were found gas-producing but no record was kept. In 1890"
I isolated an anaeérobe, probably identical with the bacillus of
malignant cedema, from the organs of a pig. I append asome-
what incomplete record of gas production in the fermentation
tube studied at that time which indicates a close relationship
to the same process in the 2. colz group:

*This bacillus has been studied from the chemical aspect by Frank-
land, Stanley and Frew"’,

212 Theobald Smith

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Proteus vulgaris. This species has certain points of con-
tact as regards morphology with the B. coli group. It differs
in possessing very active peptonizing properties as manifested
in gelatin. Its powerof gas production is peculiar in thata
smaller quantity of gas is formed than in cultures of B. colz.
It likewise is peculiarin being unable to produce gas in lactose
bouillon while its action in glucose and saccharose bouillon is
the same. Repetition of the gas test at intervals and with

213

The Fermentation Tube
subcultures which had lost almost completely the peptonizing

power gave the same result.

IX.—Proteus vulgaris.

Gas present after analog
Sugar Total at of Co; H
used. d I q 2 a 3 4 5 a 7 70° F, bulb
: 5 : : s. :
ay. | days. | days. | days ays. |, 7 sae
PECts| Pr. CL: |Pr Cor Pier Cea preeCtal| mprencts pr. ct. Precte
Glucose. ..|- 4 20 28 aa 35 31 Acid 28 72
2 5 — 8 10 10 Alkaline | Trace |Nearly 100
Lactose. . | |
o* (0) Oo @) — — ce met ==
6 20 30 34 36 a9 Acid 39 61
Saccharose.
—* | 24 | 36 | 32 | 33 (6th) | 32 (6th) - 33% 66%

* Bouillon I of Table I containing no muscle glucose. The rest is bouillon H,
containing a trace.

214 Theobald Smith

The Bacillus-Cloace Type of Gas Production.—The types of
gas production hitherto described present certain underlying
characters which suggest a closerelationship. ‘These I group
together as the B&B. coli type since it differs quite markedly
from the type now to be described.

The species known as B. cloace was first described by E. O.
Jordan” as coming from sewage. ‘The cultures which I have
ranged under this name have been obtained, with one exception,
from water both polluted and unpolluted. The exception was
reputed to have come fromcornstalks. It istherefore a widely
diffused organism whose true habitat I do not know, although
I am strongly of the opinion that it is an organism living on
decaying vegetable matter. If so, its name is unfortunate as
it could not be regarded as a sewage bacterium strictly speak-
ing. It is a small bacillus closely resembling B. cold in form
and size and is actively motile. On gelatin the surface colo-
nies appear at first as thin expansions with slightly irregular
outline. T'wo or three days after the colonies have appeared,
liquefaction sets in. This peculiar retardation of liquefaction
is noteworthy and in general, it may be said, that the rapidity
varies slightly from culture to culture and is gradually weak-
ened during artificial cultivation. Milk I find coagulated
only after seven or eight days. On potato a fleshy, pale yel-
lowish, not characteristic growth appears after one or more
days. I may state here that two varieties of this species have
come under my observation which I designate provisionally
aand B. Fora, the bouillon becomes uniformly turbid, for 8
very feebly so with a tendency of the growth to form flakes
somewhat like the flocculi of anthrax cultures. Evidently
there is in Ba greater tendency towards cohesion of the
bacilli.

The gas production of 2. cloace is very rapid in glucose and
saccharose bouillon and slow in lactose bouillon.

The Fermentation Tube 215

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nian bee 5
a
2]
ht Ww oO et
oh aie CoP shes Crake a5
an > co 2
yo}
on fon) ie) 5 QO
“I aon
Cath Tena eos SE Sicon folic O
n aS fon tad 8

This type of gas production differs from the 2. cold type: 1,
in the much greater accumulation of gas which drives out all
of the fluid from the closed branch in two or three days ; 2, in

the much larger proportion of CO,, the fraction a5 varying

from % to %; 3, the much feebler acid reaction of the fluid
in the open bulb. ‘The lactose fermentation goes on at a slow
steady pace and after one or two weeks a considerable quan-
tity of gas has accumulated in which the relative quantity of
CO, and H varies considerably.

216 Theobald Smith

The behavior of 2. cloace in the fermentation tube reminds
us of the action of ordinary yeast under the same conditions.
There is in both the same rapid evacuation of fluid from the
closed branch. ‘The fundamental difference between the two
processes, however, is the invariable presence of H in cultures
of the bacterium.

eo
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~ n (3)
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Ay so} Ay
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. ~~ [asf +e [oe]
a ‘s CMAs:
See ei pa Res
& x In a7 Oo 6
“< a ss] uw pa wy
a) 3 Lio} Py
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s 5 = 4 a oO
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8 ow a 3
re)
yy oO CON i Oi renee
S cv eu
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w
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12)
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129)

The Fermentation Tube 217

Among the more important bacteria which have been tested
in the fermentation tube and which fail to set free any gas
may be mentioned the following :

Staphylocci.

Streptococci.

Septicemia hemorrhagica (rabbit septicaemia, swine plague,

fowl cholera, W2zldseuche, etc.)

B. typhi abdominals.

The various comma bacilli (Spzrillum chol. Asiat. ; Sp.

Deneke, Finkler and Prior, Smith.)

B. anthracis.

Many aérobic spore-bearing bacilli.

B. mallet.

Concerning that strictly aerobic species, B. subtzlis, Vande-
velde’® finds,contrary to earlier determinations of Prazmowski”,
CO, and H given off in varying quantities. Obviously the
former worked with impure cultures. The absence of gas
production in cultures of B anthracis was pointed out by Ar-
loing* in 1886.

SOME GENERAL OBSERVATIONS ON THE PRODUCTION OF GAS
BY BACTERIA AND ITS RELATION TO THE FORMATION OF
ACIDS IN THE CULTURE FLUID.

A consideration of the results obtained with the fermenta-
tion tube develops a number of interesting phases of bacterial
life. Perhaps the most important fact to be gathered is the
fundamental character of gas production not only in distin-
guishing species but groups of species. The phenomenon of
fermentation as expressed by gas production may in fact be
called a group reaction. It is, for example a common charac-
ter of a large group of motile bacteria which we may desig-
nate the B. coli group. While it is absent in other equally
large and important groups such as Septicemia hemorrhagica
and the comma bacilli. I regard, therefore, the production
of gas not as one of the large number of minor differential
characters by which we are in the habit of fixing a species
but as one of fundamental importance, associated with groups
of bacteria having perhaps a common phylogenetic origin.

218 Theobald Smith

In view of the presumable importance of gas production*
the question may be asked as to the permanence of this func-
tion. The permanent or temporary character, under cultiva-
tion, must largely decide for or against the position taken
above as to the fundamental importance of kinds of fermenta-
tion in the grouping of bacteria. The facts which I have col-
lected are necessarily meager since I have employed the fer-
mentation tube only for four years, and no other person has
thus far paid any attention to this subject. A few facts, how-
ever, bear on this point. J have not yet encountered any bac-
teria which have either gained or lost the gas-forming func-
tion under cultivation. In the colon group it does not appear
to vary at all from year to year. The same persistence was
observed in Proteus vulgaris. Of two varieties originally de-
scended from the same colony, one still actively liquefying gel-
atin, the other having lost this power almost absolutely,
both produce the same amount of gas in glucose and saccha-
rose bouillon. Recently I have noticed in one of the cultures
of B. cloace, over a year old, a slight diminuition in the total
quantity of gas set free in saccharose bouillon. In glucose
bouillon the function seems to be intact. While, therefore,
the power of gas production may be slightly reduced quanti-
tatively it does not disappear. It likewise is, at least for
Proteus vulgaris, a much more permanent function than that
of secreting a liquefying ferment.

More or less related to an enfeeblement of the fermenting
power observed in the space of months and years in the same
culture, is an incapacity probably the result of an adaptation
to a parasitic existence. This is very well illustrated by the

*I simply use this word as standing for types of fermentation which
need more careful examination by chemists than they have hitherto
received.

{In opposition to my observations is one recorded by Arloing’, A
micrococcus septicus puerperalis (probably a streptococcus or a staphy-
lococcus) produces no gas when fluids containing sugar are inoculated
from old cultures. When, however, young cultures twenty-four to
thirty-six hours old are used for inocculation, CO, and H are given off
abundantly. Such a remarkable change of function must rest upon
some experimental error of the author.

The Fermentation Tube 219

colon group which may be divided into a saprophytic and a
parasitic sub-group as follows :

A. Saprophytic sub-group.
ta. Ferment all three sugars with same rapidity.
Bacillus of grouse disease and some colon bacilli.
tb. Ferment glucose and lactose rapidly, saccharose

slowly.) Vous. 2. col a (ra andsrb):
2. Ferment glucose and lactose rapidly, saccharose not
Aa eae soe, ene COLE ae

B. Parasitic sub-group. ;
1. Ferment glucose rapidly, saccharose and lactose not
at alin. 4. all pathorenic forms:

Iam inclined to associate this loss of functional activity in
the pathogenic group B with an adaptation to a more para-
sitic existence and the development of certain other powers—
the formation of toxic substances perhaps—which enables them
to live in competition with living tissues while they have
largely forfeited their power to compete with the more sapro-
phytic forms from which they may have originally sprung.

It might be claimed that the phylogenetic loss of gas pro-
duction is simply a change in the kind of fermentation, from
the butyric to the lactic for example. That this is not true
can be readily demonstrated, for in saccharose and lactose
bouillon, when muscle glucose is absent and no gas appears
in consequence, the reaction of the bouillon does not become
acid. Among those bacteria which act upon sugars without
the development of gas, a strongly acid reaction appears with-
in twenty-four hours. .The failure of the group B to act upon
lactose is furthermore shown by their inability to produce
coagulation of milk. We have, therefore, no ground for as-
suming a change in the type of fermentation. It is an abso-
lute loss of function and not a modification.

In bringing together the more detailed observations on gas
production a certain number of interesting facts claim our at-
tention. We note that in the 2. colz type of gas production in
glucose only a certain quantity of gas collects—45 to 60 per
cent. of the capacity of the closed branch—while in the 2.

220 Theobald Smith

cloace type fully 100 per cent. is formed. Again the fraction
H*
Co,
yor. The reaction of the fluid in cultures of the latter is
feebly acid while for the 2. coli group it is always strongly
acid. Grimbert” in his studies of an anaérobic organism
ascribes the greater production of CO, to a greater formation
of alcohol and the more abundant production of H to a greater
formation of acid in accordance with the following formule :

for B. cold is approximately # while that for B. cloace is

OH O=CO 44co.2 ar eee

iCOR ee

Rees | fe)
C,H,,.0;=C BO 2CO4- 1.0); ==
CO; tea

This would agree well with the feebly acid reaction of cult-
ures of B. cloace and the strongly acid condition of those of B.
colt,

Another phenomenon constantly observed is the great pre-
dominance of H over CO, in either type when only a little gas
has been formed as in peptone bouillon containing traces of
muscle sugar. The same phenomenon is noticeable when the
gas at different stages of the process is examined. This may
be illustrated by the three following stages in the gas produc-
tion by 2. cloace.

After 22 hours 37.5 per cent. gas has accumulated; CO,,
46.6 per cent. ; H, 53.4 per cent.

After 22 hourst 73 per cent. gas has accumulated ; CO,, 61
Percent. 5H, 2o"per’cent.

After 96 hours 95 per cent. gas has accumulated ; CO,, 70
per cent. ; H, 30 per’ cent:

* We should not ascribe more than a comparative value to this frac-
tion for the reason that Co,is much more soluble in water than H.
Thus at 20° C. one volume of water takes up 0.9014 volumes of CO, and
only .or93 volumes of H. If we bear in mind that at the beginning of
fermentation a comparatively large quantity of CO, may become ab-
sorbed in the bouillon the relation of CO, to H in the fermentation tube
will be understood to be entirely different from the ratio obtained by
exact analytical methods.

ft Asecond tube inoculated with the first but having produced gas
more promptly.

The Fermentation Tube 221

I have been inclined to ascribe this to the absorption of CO,
by the bouillon but Grimbert™ as well as Frankland” finds by
exact quantitative determinations of the gases the same in-
crease of CO, as the fermentation progresses. ‘The former ex-
plains it by assuming a greater production of alcohol in the
later course of the process in accordance with the formule
given above. According to this explanation the type of fer-
mentation of 2. cloace may differ from that of B. coli simply by
an increased production of some alcohol at the expense of an
acid. If we goa step farther and bring within the range of
comparison another type of gas production, that of ordinary
yeast by which only CO, and ethyl alcohol are produced (if
we neglect traces of succinic acid) we have eliminatcd both
the hydrogen and the acid element which seem to go to-
gether.

A farther point of interest is the constant presence in all
cultures examined of an inflammable, explosive gas which I
have assumed to be hydrogen. Most observers, including Ar-
loing*, Escherich’, Frankland”, Peré’, Scruel, Grimbert”,
and others report only CO, and H. Baginsky” on the other
hand claims the presence of CH, as well. It would be interest-
ing to determine whether bacterial fermentation ever goes on
without the evolution of both CO, and H at the same time.

In examining the action of bacteria on the three sugars
used, we note that the gas production in glucose bouillon is
always rapid though it may be slow or absent in lactose and
saccharose bouillon. Glucose is thus the sugar most easily
acted upon. A curious preference is shown by certain species
for certain sugars. Thus 2. colz produces gas rapidly in lac-
tose and slowly or not at all in saccharose bouillon. Fried-
lander’s bacillus on the other hand, acts vigorously upon
saccharose and very slightly upon lactose. The latter is not
touched by Proteus vulgaris at all. By pushing such com-
parative inquiries still farther and including other carbo-hy-
drates, as has been done by most of the authorities cited above
from a slightly different point of view, still finer lines of dis-
tinction might be drawn. Owing to lack of time I have not

222 Theobald Smith

gone beyond the three sugars noted excepting to test some
species in potato starch suspensions several years ago.*""

The source of the two gases CO, and H may be explained
by the old formula of the text-books which splits one mole-
cule of grape sugar into two of lactic acid and these into one
of butyric acid and two each of CO, and H. This formula
demands equal volumes of these gases. Scruel holds that the
molecule of glucose breaks up into one of formic, of acetic,
and of lactic acid with fixation of one atom of O. The gases
he derives from the direct decomposition of the newly formed
molecule of formic acid :

CH,0O,= CO, + H,.

As has been recently emphasized by Grimbert and stated
above, the process of fermentation varies from beginning to
end so that no single equation can express more than what is
going on at any one time. The same author ascribes this
continual change toa modification of the vitality of the fer-
ment organism brought about by the accumulation of harm-
ful products in the fluid.

The rapid evolution of gas in the presence of one kind of
sugar and its slow accumulation in the presence of another
brings up the question whether or not an inverting ferment
comes into play in the slow fermentation. This question is
not approachable by the simple methods I have employed.
It is certainly a curious fact that one bacterium may produce
gas with almost equal rapidity in three sugars, another in two
and that these two may be, with one species, glucose and sac-
charose, with another, glucose and lactose. Thus the bacillus
of grouse disease produces gas in glucose, lactose and saccha-
rose with equal rapidity.

Bacillus coli produces gas in glucose and lactose with equal
rapidity. Action on saccharose variable.

*The action of bacteria on potato starch may be demonstrated by
cutting potatoes so that they fit rather snugly into test tubes. The film
of water between them and the glass imprisons any gas bubbles that
may be set free. In this way I noted the evolution of gas in several
species, among them Friedlander’s bacillus.

The Fermentation Tube 223

The bacillus of Friedlander produces gas in glucose and sac-
charose with equal rapidity. Very slight action on lactose.

Proteus vulgaris produces gas in glucose and saccharose
with equal rapidity. No action on lactose.

Bacillus cloace produces gas in glucose and saccharose with
equal rapidity. Action on lactose slow.

The probability of the direct breaking up of the molocule
of saccharose and lactose’ without inversion, has been affirmed
by nearly all recent authorities and seems plausible when gas
accumulates very rapidly as in cultures of B. cloace, It is
evident that the observatious made with the fermentation tube
open some very interesting problems, the solution of which
must be left to others.

In connection with the selective action on sugars manifest-
ed by different species seemingly related to each other the
thought has occurred to me that a clue to the habitat of bac-
teria might be obtained by an investigation of their predilec-
tions. Inasmuch as there are certain products such as lactose
peculiar to animals, and certain others, such as saccharose
peculiar to plants an adaptation to one or the other carbo-
hydrate wou'd indicate a saprophytic existence on animal or
vegetable products. This hypothesis however needs a larger
array of facts than I am able to put together, to prove or dis-
prove its correctness.

The production of CO, and H together with other gases
during the decomposition of proteid substances has been af-
firmed by Kerry* and Bovet’*. The former used carefully
prepared serum-albumin, the other serum-albumin and yolk
ofeggs. In the accurate determination of the source of gas
production in putrefactive processes, it is evident that carbo-
hydrates must be carefully eliminated since the fermentation
of these substances with evolution of CO, and H seems to be
such a wide spread function among bacteria.

There is one other phase of the subject of fermentation
which has an important bearing upon bacteriology. I refer
to the formation of acids * which seems to be clearly traceable

* Thus in milk cultures of ZB. colz, Baginsky! found formic, acetic,
aud lactic acids. The same were found by Scruel. Peré’7 detected ace-
tic and lactic acid. Frankland, Stanley and Frew” determined, in cul-

224 Theobald Smith

to the presence of carbo-hydrates. Some years ago, Petru-
schky”™ examined the acid and alkali-producing functions
of bacteria by using as a culture medium specially pre-
pared whey from milk. I called attention to the fact that
such classification had only a limited value since it depended
entirely on the composition of the culture fluid’. The whey,
having as an important ingredient, lactose, would prove only
such bacteria acid-producing which were able to cause fermen-
tation of the milk sugar while those which could not do this
would show themselves as alkali producers. Bearing on this
subject are the statements made by bacteriologists in the early
days of this branch of biology that cultures of many bacteria
are at first slightly acid before becoming alkaline. I suggest-
ed that this was probably due to traces of sugar in the culture
fluid and I was able to prove this by causing an oscillation
from an acid to an alkaline reaction and back again by adding
at intervals small quantities of glucose to the bouillon. The
alkali formed during the multiplication of bacteria was neu-
tralized by the acid derived from the fermentation of the glu-
cose. If this was small in quantity the acid or acids were
formed in correspondingly small quantities and the alkaline
reaction soon reappeared. I was able to show furthermore
that the addition of small quantities of fermentescible sugar
greatly favored the multiplication of bacteria by keeping
down the alkaline reaction.. After I began testing peptone
bouillon for muscle glucose with gas-producing bacteria, I
found that in bouillon free from sugar the multiplication of
various acid producing bacteria such as streptococci, staphylo-
cocci, B. typhosus, B. diphtheria, B. coli, and B. cholere suisisnot
attended with any acid reaction, either temporary or permanent.

So far as my observations have gone they show that all bac-
teria are alkali producers in bouillon free from carbo-hydrates,
and that when one or the other of this group is present a very
large number of the most easily cultivated bacteria are acid
producers. This two-fold activity probably serves a useful
purpose in keeping the medium in which they live more or

tures of the bacillus of Friedlander ethyl alcohol, acetic acid and a little
formic and succinic acid. Grimbert?’ detected among the products of
B. orthobutylicus normal butyric alcohol, butyric and acetic acid.

The Fermentation Tube 225

less neutral and therefore favorable to their continued multi-
plication. A good illustration of this fact is afforded by the
growth of &. co/7 in saccharose bouillon. The gas production
goes on (with most varieties) very slowly. The fluid in the
bulb in contact with the air becomes alkaline and very turbid
with growth. The fluid in the closed branch becomes acid
under the influence of the slow fermentation and remains so.
As it is gradually pushed out into the bulb by the slow accu-
mulation of gas it tends to reduce, by degrees, the alkalinity
of the fluid therein contained and thus favors step by step, the
growth which finally becomes very dense.

The employment of sugar as a constituent of culture media
is therefore, a matter of considerable importance. For certain
species, like &. coli for instance, the addition of 1 per cent.
glucose or lactose would be a decided detriment to the culture
and soon lead to its destruction. Cane sugar on the other
hand, added in the same proportion, would favor the growth
owing to its much slower decomposition. Again the addition
of very small quantities of glucose from time to time is favor-
able as stated above. In fact, bouillon, entirely free from
muscle glucose, is less desirable than that containing traces,
and in general it would be well to add glucose to bouillon.
The limit may safely be put at o.1 per cent. These remarks
apply equally well to the large group of bacteria which pro-
duce acids in sugar solutions without the evolution of gas and
in searching for the most favorable media for any species its
behavior toward the more common carbo-hydrates should be
carefully looked into.

APPLICATION OF THE FERMENTATION TUBE TO PROBLEMS
IN PRACTICAL SANITATION. THE GAS TEST IN THE DIF-
FERENTIATION OF B. TYPHOSUS FROM THE B. COLI GROUP
OF BACTERIA.

The use of the fermentation tube as an important differen-
tial test in bacteriology led me in 1889 to compare the fre-
quently confounded species, B. typhosus and B. colt communis.
A sharp distinction was at once detected between them which
manifested itself by a total lack of gas production on the part

226 Theobald Smith

of the typhoid bacillus. Ina brief article on the uses of the
fermentation tube published in 1890’, I incidentally called at-
tention to this difference asa valuable means of diagnosis.
The fact, however, remained unnoticed and in 1891 Chante-
messe and Widal” brought forth the same test as new, using
lactose in place of glucose in the bouillon. ‘Their method
consisted in observing gas bubbles rising and forming a light
froth on the surface of the culture fluid in ordinary flasks.
This publication induced me to defend my priority in a sécond
article in which I quoted the original announcement of the
test”. But even this has been largely overlooked by subse-
quent writers.

The publication of Chantemesse and Widal first called gen-
eral attention to the gas test as the older differential characters
were melting away and something more definite was urgently
needed in this very practical field. They were opposed at
once by Dubief” who regarded the differences between these
species as merely quantitative. Recently a number of writers
(Tavel”, G. W. Fuller”, W. Dunbar’, Germano and Maurea”,
Ferrati”, and Pane”,) have contributed long articles on this
subject and all of them confirm the gas test and give it the
most important place among the means of diagnosis between
B. typhosus and the colon group. Dunbar in ignorance of my
second article * naively recommends the bent tube, closed at
one end, as the simplest means of determining gas production.
The same thing had been suggested by G. W. Fuller in a
prior publication as a substitute for the more expensive fer-
mentation tube. Dunbar further recommends ‘simple bouillon
(Fleischwasser), a recommendation likely to lead astray as I
have pointed out above. Since gas production in bouillon de-
pends solely on the muscle glucose the test would fail when
this is absent. The use of lactose, as suggested by Chante-
messe and Widal is not so trustworthy as that of glucose, for
we have a large group of pathogenic bacilli, the hog cholera
group, easily confounded with &. typhosus because neither act
on lactose and hence do not coagulate milk. The use of glu-
cose bouillon would clear up the difficulty at once.

* This must have appeared before the conclusion of his work for he
refers to a publication subsequent to mine.

The Fermentation Tube 227

The fundamental differences between 2. tyfhosus and the
colon group of bacteria need further elucidation by a thorough
study of all the products of fermentation, as has been done by
Dubief* and Peré,’ but without concordant results as yet.
For the typhoid bacillus likewise has a definite action on glu-
cose, as has been shown by Brieger and recently by Peré.
The latter has shown that when glucose is added to milk, it
subsequently coagulates when inoculated by this organism.
The action on glucose is moreover readily revealed by the
markedly acid reaction of cultures in glucose bouillon. All
that the gas test tells us definitely is that the colon bacteria
act on glucose with evolution of a certain volume of gas, and
that the typhoid bacillus acts upon glucose without the evolu-
tion of gas.

There is one question called up by the fermentation test
which will require some attention. The evolution of gas with
the simultaneous appearance of acids in the culture fluid might
lead us to assume that at least some gas may have been set
free from the Na,CO, used to neutralize the bouillon. Yet by
adding increasing quantities of sterile Na,CO, solution to a
series of fermentation tubes, I was unable to evolve any gas
with the typhoid bacillus. It is not unlikely, however, that
bacteria capable of setting free much acid may lead to the ac-
cumulation of a trifle of gas, not the product of fermentation, in
strongly alkaline bouillon. In all cultures in which only
small quantities of gas appear this possibility should be borne
in mind.

THE QUANTITATIVE DETERMINATION OF FECAL BACTERIA IN WATER.*

The bacteriological examination of water in the interest of
practical hygiene, has thus far suffered from the difficulty that
the kinds of bacteria present are recognizable only when a
disproportionate amount of labor is spent in isolating them.
Occasionally bacteriological water analysis has taken a certain

* See the forthcoming Annual Report of the State Board of Health of
New York for 1892, for a more detailed statement of this method.

228 Theobald Smith

definite direction, as in the search for typhoid bacilli and
Asiatic cholera spirilla. For general purposes, however, the
bacteriologist had to fall back upon the numerical estimation
with no regard to any qualitative determination. The nu-
merical estimate, taken by itself, is not satisfactory. Itis true
that in large surface waters, such as rivers, the number of bac-
teria is a very good index of the organic matter present, yet
here one remains in doubt whether the bacteria are in the
main from sewage or from decaying vegetable matter. Hence
in the few instances in which I have had occasion to determine
the hygienic character of a given water, I have endeavored to
get some idea of the fecal bacteria present, in other words, the
large group of colon bacteria which are such regular inhabi-
tants of the intestines of man and of the domesticated animals
and which are as good an index of sewage pollution as we
can desire.

There are methods which enable us to isolate fecal bacteria
from water, but they either do not give us any information
concerning the number of such bacteria, or else this knoledge
is obtainable only after much labor. Passing by these meth-
ods as not bearing on our subject, I will briefly refer to one
which is an outgrowth of the observations on gas production
in the fermentation tube.

If a series of such tubes containing glucose bouillon be in-
oculated, each with an equal but very small quantity of water
and placed at once in the thermostat at 37° C., it will be no-
ticed after one or more days, if the water is much polluted,
that some contain gas. If, for example, one ccm. of water is
distributed equally among ten tubes and of these, four subse-
quently contain gas, we may conclude that in one ccm. of this
water there were four gas-producing bacteria. All gas-produc-
ing bacteria are not intestinal species, however. Hence we must
try to eliminate those that are not fecal by the amount of gas
present. Bringing together all the information obtained by
cultivating a variety of bacteria in the fermentation tube, I
have come to the conclusion that all tubes containing less than
forty and more than seventy per cent. of gas are to be elimin-
ated. The lowest limit drawn excludes Proteus vulgaris,

The Fermentation Tube 229

probably a putrefactive organism, pure and simple. The up-
per limit excludes B. cloace, which, in spite of its name, I can-
not range among fecal bacteria. Between the limits of forty
and seventy per cent. of gas are included all varteties of B.
coli, the hog cholera group, ZB. lactis aérogenes and Friedland-
er’s bacillus.

There are several objections which may be urged against
this as against any approximative method. In the first place
it does not include a large number of pathogenic species,
among them #. typhosus and Sp. cholere Asiatice. But, it may
be answered, the object of the method is not to reveal all pos-
sible disease germs but to use the colon group as an index of
pollution because, as I maintain, they must come directly
from the digestive tract. The presence of 2. colz even in
small numbers is amply sufficient to make any water sus-
pected.

In the second place it may be claimed that the evolution of
gas may be either checked or augmented in the presence of a
number of species in the same tube. This objection involves
the rather broad subject of antagonism among bacteria, which
cannot be discussed here. There are, however, a few facts
which show the objection to be in the main pointless. In the
thermostat only very few bacteria from water develop owing
to the high temperature, so that rarely more than one species
survive and multiply in the fermentation tube if the quantity
of water added be not too great. Again, the presence of two
gas-producing bacteria in the same tube is not likely to occur
owing to their relative scarcity. To test their mutual behav-
ior, however, I inoculated a number of tubes simultaneously
with two different gas-producing species. In general B. colz
produced the quantity of gas peculiar to it, unless B. cloace
was inoculated with it. In one out of three trials B. clo-
ace triumphed and drove out all fluid from the closed branch,
in the other two &. cold conquered. There may, therefore, be
an occasional masking of the presence of 2. coli by B. cloace.
This error will not occur if small quantities of water be used
or if the experiment be repeated in the event that more than
half the tubes inoculated show gas production.

230 Theobald Smith

The concurrence of the many aerobic bacteria with the colon
group in the fermentation tube even if they should be able
to multiply at the temperature of the thermostat is made neg-
ative by the fact that the former are unable to multiply at
all in the closed branch.

WASHINGTON, D. C.,
July 28, 1893.

INDEX TO PUBLICATIONS REFERRED TO IN THE TEXT.

Lon)

10.

II.

i225

£3.

14.

15.

. M. Einhorn. Archiv f. pathol. Anatomie, CII. S. 263.
. Theobald Smith. Das Gahrungskdlbchen in der Bakteriologie.

Centralblatt f. Bakteriologie u. Parasitenkunde, VII, (1890). S.
502.

. Th. Escherich. Die Darmbacterien des Sauglings. 1885.
. S. Arloing. Propriétés zymotiques de certain virus. Compt. rendus

des seances de 1’ Académie des Sciences, CI, (1885-11). p. 819.

. Wm. Dunbar. Untersuchungen iiber den Typhus bacillus and den

B. colicommunis. Zeitschrift fiir Hygiene, XII, (1892). S. 485.

. Claudio Fermi. Weitere Mittheilungen iiber die tryptischen

Enzyme der Mikroorganismen. Archiv f. Hygiene, XIV, (1892).
p21.

. Peré. Contribution a4 la biologie du bactérium coli commune et du

bacille typhique. Annales de l’Institut Pasteur, 1892. p. 512.

. N. Pane. Sulla diversa quantita di glucosio che si trova nel brodo

in rapporto al diverso grado di fermentazione di alcuni batteri.
Rivisti clin. e terapeut, 1892, (October). pp. 577-581.

. Theobald Smith. Einige Bermerkungen iiber Saure- und Alkali-

bildung bei Bakterien. Centralblatt fur Bakteriologie, VIII,
(1890). S. 389.

Gilbert et Leon. Contribution a l’étude des bactéries intestinales
(memoire). Compt. rend. hebd. de la Soc. de Biologie, 1893.
No. II, p. 55.

E. Klein. Ueber sine akute infektidse Krankheit des schottischen
Moorhuhnes. Centralblatt f. Bakteriologie, VI. pp. 36, 593.

A. Baginsky. Zur Biologie der normalen Milchkothbacterien, II.
Zeitschrift fiir physiol. Chemie, XIII. S. 352.

Seruel. Contribution 4 l’étude de la fermentation du bacille com-
mun de l’intestin. Archives méd. belges. 1892-11, pp. 362-367;
1893-1, pp. 9-33, 83-96.

Gartner. Ueber die Fleischvergiftung in Frankenhausen am kyffh.
u. den Erreger derselben. Correspondenzblatt d. allg. arztl.
Vereins von Thiringen. 1888.

Fr. Loffler. Ueber Epidemien unter den im hygienischen Institute
zu Greifswald gehaltenen Mausen und uber die Bekampfung der
Feldmausplage. Centralblatt f. Bakteriologie, XI, (1892). S.
129.

232 Theobald Smith

16.

17/6

18.

19.

20.

21.

22.

23:

24.

25.

26.

27.

28.

29.

30.

cus

aD:

33:

Theobald Smith. Kleine bakteriologische Mittheilungen. Central-
blatt fir Bakteriologie, X, (1891). p. 180.

Frankland, Stanley, and Frew. Fermentations induced by the
pneumococcus of Friedlander. Journal of the Chemical Society
of London, LIX. pp. 253-270.

Theobald Smith. Special report on the cause and prevention of
swine plague. Washington, 1891. p. 81.

E. O. Jordan. Experimental Investigations by the. State Board of
Health of Massachusetts upon the Purification of Sewage, etc.
Part II, p. 824.

G. Vandevelde. Studien zur Chemie des Bacillus subtilis. Zeit-
schrift fiir physiologische Chemie, VIII. S. 367.

A. Prazmowski. Untersuchungen uber die Entwicklungsgeschichte
und Fermentwirkung einiger Bakterienarten. 1880.

I. Grimbert. Fermentation anaérobie produite par le Bacillus
orthobutylicus, ses variations sous certaines influences biologiques.
Annales de |’Institut Pasteur, VII, (1893). pp. 353-402.

Kerry. Ueber die Zersetzung des Eiweisses durch die Bacillen des
malignen Oedems. Sitzungsber. d. Kaiserl. Akademie d. Wis-
senschaften in Wien. 1889.

Bovet. Des gaz produits par la fermentation anaérobienne. An-
nales de Micrographie, II. p. 322.

J. Petruschky. Bakterio-chemische Untersuchungen. Centralblatt
f. Bakteriologie, VII, (1890). S. 49.

Chantemesse et Widal. Differentiation du bacille typhique et du
bact. colicommune. Compt. rend. Soc. Biologie, 1891. p. 747.
Theobald Smith. Zur Unterscheidung zwischen Typhus und

Kolonbacillen. Centralblatt f. Bakteriologie, XI, (1892). S. 367.

H. Dubief. Sur la biologie comparée du bacille typhique (bacille
d’Eberth-Gaffky) et du Bacillus coli communis—Leur action sur
les sucres. Compt. rend. Soc. Biologie, 1891. p. 675.

HE. Tavel. Caractéres differentiels du bacterium coli commune et
du bacille typhique. La Semaine méd., 1892. p. 52.

Geo. W. Fuller. The differentiation of the bacillus of typhoid
fever. Boston Med. and Surg. Journal. 1892, Sept. 1.

E. Germano u. Giorgio Maurea. Vergleichende Untersuchungen
tuber den Typhusbacillus und ahnliche Bacillen. Beitrage z.
pathol. Anatomie, XII, (1893). S. 494.

Ferrati. Zur Unterscheidung des Typhusbacillus vom Bakterium
colicommune. Archiv f. Hygiene, XVI, (1893). S. 1.

Nicola Pane.. Sulla proprieta de dacillus coli communis di svilup-
pare gas, et sua importanza diagnostica per distinguerlo dal
bacillo del tifo in rapporto ad altri caratteri. Gazetta delle
Cliniche, III, (1892). p. 369.

FERMENTATION TUBES—THEOBALD SMITH.

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

DESCRIPTION OF PLATE.

(All figures reduced one-half.)

1. The fermentation tube as used in the foregoing investigations.
a, The bulb freely exposed to the air filtering through the cotton
wool plug; 4, the closed branch; c¢, the connecting tube; d, the
foot. The tube used in the foregoing investigations requires
about 25 cc. of bouillon, 20 of which belong to the closed branch.
The line ay divides the aérobic from the anaérobic portion of the
tube. This line is very sharply drawn by aérobic bacteria. The
turbidity on the one side bounds absolute clearness on the other.
In facultative anaérobic cultures there exists at this line a sud-
den marked change from turbidity to mere cloudiness.

2-8. Graphic representation of gas production by different bacteria
in different sugar solutions. The short lines on the left margin
of the tube show the rapidity with which gas accumulates and
serve as a means of comparing different types. The volume of
CO, and H found at the close of the period of gas production is
indicated by brackets on the right margin of the tube.

2. B. coli communis in glucose bouillon.

3. The same bacillus in lactose bouillon.

4. The same bacillus in saccharose bouillon.

5. &. cloace in glucose or saccharose bouillon.

6. BL. cloace in lactose bouillon.

7. Saccharomyces cerevisie (isolated from compressed yeast) in
glucose or saccharose bouillon.

8. B. coli in peptone bouillon. The gas formed indicates the
presence of considerable muscle glucose.

AO TONG

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Pishit Mien
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rine nh) ;

MUSCULAR ATROPHY CONSIDERED AS A
SYMPTOM.

By WILLIAM CHRISTOPHER KRAUSS.

Atrophy, or wasting of the muscular fibers, whether occur-
ring insidiously or ez masse may or may not be indicative of
disease of the nerve centers. Although not of such serious
import that its recognition demands early therapeutic pro-
cedures, nevertheless, it is necessary to detect the cause of
this retrogression in order to render a correct prognosis and to
plan the proper treatment. Diseases of the brain and spinal
cord are, asarule, sub-acute or chronic, run a long course,
manifest themselves by vague, indifferent symptoms and
yield grudgingly to the resources at the neurologist’s com-
mand. Wasting of the muscles is one of the most prominent of
the objective symptoms of brain and cord disease, and if proper-
ly considered and appreciated may give us important clues for
the location and detection of the neural lesion with which we
are confronted. It is by no means pathognomonic, but when
associated with other groupings of subjective and objective
symptoms, becomes at once characteristic of definite lesions
in the brain, cord, peripheral nerves or muscle itself.

The premise must not be inferred, however, that all muscle
degeneration is pathological or dependent upon some initial le-
sion in the nerve centers, for it is a fact that wasting of muscles
occurs independently of any nerve or muscle lesion, but is due
to purely physiological changes, or the active cell growth is
no longer predominant, and has been succeeded by a period of
involution or cell decay. This we call senile wasting or
acute atrophy. Another form of atrophy, or lack of develop-
ment, which must not beconfounded with either physiological
or pathological wasting,is aplasia and hypoplasia of the extrem-
ities, conditions arising in utero due to the arrested develop-
ment of the embryo asa whole or in part. These developmental

236 William Christopher Krauss

defects are the result probably of some constriction or pressure
from folds or bands of the foetal membranes, or by loops of the
umbilical cord. Cases of this kind are by no means rare but
have been carefully studied by Foerster, Voight, Gruber and
others. The different classes are distinguished according to
the degree of malformation as follows :

(1) Amelus. Limbs entirely wanting or replaced by wart-
like stumps.

(2) Peromelus. All four extremities stunted.

(3) Phocomelus. Limbs consisting merely of hands and
feet sessile upon the shoulders and pelvis.

(4) Micromelus. Limbs regular in form but abnormally
small.

(5) Abrachius and Apus. Absence of upper limbs, while
the lower are well formed, and v7ce versa.

(6) Perobrachius and Peropus. Arms and thighs normal ;
forearms and hands, legs and feet malformed.

(7) Monobrachius and Monopus. Absence of a single upper
or lower limb.

(8) Sympus apus and Sympus opus. Absence of feet; or
they may be represented by single toes, or by one foot as in
siren monsters.

(g) Achirus and Perochirus. Absence or stunted growth
of the entire hand or foot. (Ziegler.)

It is not the purpose of this paper to invade the field of ter-
atology, but to study another morbid process which also ends
in defect of structure, not, however, through interference of
growth, but through the destruction and degeneration of
muscles once able to perform work measured by their develop-
ment and vitality. This process is more properly termed re-
gression or retrogression, and the designation muscular
atrophy as commonly employed has reference only to a retro-
grade metamorphosis of a fully developed muscle.

Inasmuch as there are atrophies due to physiological and
also others due to pathological processes it is of the utmost
importance to distinguish between them. Generally speak-
ing, physiological atrophy occurs as the result of the decadence
of the vital powers due to senile changes. It is not attribut-

Muscular Atrophy Considered as a Symptom 237

able to any direct appreciable lesion and the atrophy is con-
sidered as active. Another class, bordering closely upon physi-
ological atrophies, is caused by derangements in whole or in
part of the constructive organs, febrile processes, etc. ‘These
latter are considered as passive, and the atrophy is unlimited
in its extent. Local atrophies, due to mechanical hindrances,
injury to the tissues, through interference of the circulation,
and overwork are also examples of passive atrophies.

Pathological atrophies on the other hand, are the results of
demonstrable organic lesions either in the brain, cord, peri-
pheral nerves or muscles, follow certain laws in their distribu-
tion, and are accompanied by subjective and objective symp-
toms characteristic of the focal lesion.

Subjective signs.—’The advent of progressive muscular
atrophy in many cases, and especially in those other forms of
atrophy not dependent upon acute inflammatory processes,
is ushered in by some localized, deep-seated, aching pain, to
which little attention is paid. In others, some slight sensory
disturbance, as a feeling of numbness, heaviness or sharp lan-
cinating pains as in neuritis, may precede the atrophy, while
in many no warning whatever is given of the enfeeblement
which is soon tooccur. Generally, the first thing that attracts
the patient’s attention is the inability to execute certain move-
ments, which, but a short time ago, he was able to carry out
with ease and dexterity. If he be an artisan, and the atrophy
begins in the muscles of the hand, as it so often does, the
weakness will soon incapacitate him for his work ; if a laborer
and the atrophy first affects the shoulder muscles, or muscles
of the back, or if a pedestrian and the peroneal muscles suc-
cumb early, he is soon made cognizant of some loss of power,
which to him remains for some time unaccountable. This
weakness is often ascribed to overwork, exhaustion or fatigue,
and the usual remedy—rest—fails to restore to the former con-
dition. I have met patients in clinics, especially females, in
whom atrophy of the muscles of the hand and arm had existed
for years, and attention was first called to it by the physician
while examining for some other ailment. Instruments have
been devised for measuring approximately the strength of the

238 William Christopher Krauss

arm and leg muscles, and although the figures may vary
somewhat at each trial, still they are accurate enough to indi-
cate the progress of the wasting. The dynamometer is per-
haps the best instrument for estimating the power of the
flexors of the fingers and hand muscles. It consists of an
oval steel spring with a dial and index in the center. Com-
pression of the spring is indicated on the dial in pounds and
kilograms. ‘This instrument is by no means accurate or per-
fect as each succeeding trial may give a different reading ac-
cording to the strength exerted by the patient. It is my prac-
tice to take the average of two or three compressions and this
result I consider approximately correct.

For estimating the strength of the
legs several appliances have been
suggested by Dana, Birdsall, Féré,
and d’Onimus, but none have en-
joyed universal adaptation among
neurologists. An apparatus which I
have recently described * approaches,
in my opinion, the solution of this
problem, and has received the appel-
lation, Pedo-dynamometer. It con-
sists of a wide, heavy belt (@), its
inner surface padded so that its ad-
justment around the waist will not
be uncomfortable. A heavy web-
bing (4), is looped through the belt
passing over the shoulders, which
helps to retain the belt in its proper
position. A common Mathieu dyna-
mometer (c), is connected with the
belt (a), by means of a strong ad-
si : justable strap, permitting it to be

FIG. I. lengthened or shortened according to

the stature of the patient. Con-

nected to the dynamometer (c), is a stirrup (@), the base of
which is padded for receiving the foot. Pressure exerted

*Neurologisches Centralblatt, June 1, 1893.

Muscular Atrophy Considered as a Symptom 239

upon the stirrup will be registered upon the dial of the dyna--
mometer and the approximate strength of the extensors of
the leg can be ascertained. By lengthening the strap which
connects the dynamometer with the belt (@), and flex-
ing the foot on the leg as much as possible then allowing the
patient to push, the power of the extensors of the foot can be
also determined. In applying the Pedo-dynamometer, the
thigh should be flexed upon the pelvis to an angle of
135 degrees, the leg flexed upon the thigh to an angle
of go degrees at the knee. It may be adjusted in the stand-
ing or recumbent position. By using snaps the dynamometer
can be quickly removed and used to measure the power of the
hands.

In advanced cases the patient is very susceptible to changes
of temperature, particularly from warm to cold, and in win-
ter the atrophied members must be heavily padded to insure
comfort. In those cases where rheumatic pains have pre-
ceded the atrophy, and also in those cases of neuritic and
spinal origin, there is some loss of sensation and other dis-
turbances, but in the great majority of cases the eat
sensibility is unimpaired.

As a rule, pain is absent in muscular wasting except in
cases of neuritic and spinal origin, and here the pain is a
neural pain and not a muscle pain. Pressure over the course
of the inflamed nerves or on the spine will call forth sharp,
shooting pains, whereas pressure applied to the muscle will
elicit no complaint.

The objective signs offer the physician an important and
interesting field for study and observation. His attention, as
was that of his patient, is directed at once to the wasting or
atrophy of the different muscles. The natural effect of this
is to rob those portions of the body of their normal contour
and beauty, and bring into prominence the underlying hard
structures. This wasting may be limited to a single mus-
cle, to a group or system of muscles, may be unilateral or
bilateral, general or localized, according to the cause and seat
of the primary lesion. In estimating the extent of the
atrophy, some more definite means are necessary than merely
the sight or touch—and the tape measure is called into service.

240 William Christopher Krauss

A tape measure which seems to answer every purpose and
which has been cordially received by many neurologists, was
described by me in the Journal of Nervous and Mental
Diseases, 1890, page 128. It consists of a tape (1) one meter
long and one centimeter wide. The English scale is gradu-
ated on one side and the metric scale on the other. The head
is supplied with a swivel (3), through which passes the free
end of the tape, permitting of uniform tension, greater accu-
racy in reading, and of its being held with one hand.

The second tape (2) is one-half meter long and one-half
centimeter wide, and is provided with a sliding head, through
which the first tape passes. ‘This tape is, therefore, at right
angles to, and movable upon, the first tape. It is also gradu-
ated after the English and metric scales. The object of this
tape is to ascertain at what distauce from a certain fixed, bony
point the first tape has been applied, so that on succeeding
occasions the measurement may be taken at the same point.
To illustrate: If the tape (1) be applied to the arm at a dis-
tance of seven and one-half centimeters from the internal
condyle of the humerus (reckoned by means of tape 2), it is
obvious that on succeeding occasions, or in comparison of the
two extremities, the tape (1) must be applied at exactly the
same point, thus excluding all possible chance of error.

Muscular Atrophy Considered as a Symptom 241

My manner of using the tape is as follows: For the upper
arm, I select the internal condyle of the humerus as the
fixed point. Then measure off seven and one-half centi-
meters with tape No. 2. At this point the circumference of
the arm is taken by means of tape No. 1. In like manner the
circumference of the arm is noted at distances of fifteen, and
twenty-two and one-half centimeters from the fixed point.
For the lower arm exactly the same procedure is followed be-
ginning at the proximal end and taking the circumference at
seven and one-half, fifteen, and twenty-two and one-half centi-
meters from the internal condyle. For the hand a distance of
ten centimeters is measured from the tip of the middle finger
and the circumference taken at this point.

For measuring the circumference of the leg, I employ the
internal condyle of the femur as the fixed point and take
measurements at seven and one-half, fifteen, twenty-two and
one-half, and thirty centimeters respectively from the internal
condyle. In taking the circumference of the abdomen or
thorax I choose the umbilicus as the fixed point.

The atrophy of muscular fibers and the hyperplasia of the
connective tissue lead to contraction of the latter, and perma-
nent contractions and distortions of the body and extremities
result ; the same is produced if a system of muscles becomes
affected and the opponents, remaining intact, predominate.
The peculiar shape of the hand in the Duchenne-Aran type,
sometimes called ‘‘ main en griffe,’’ the ‘‘turkey gait’’ in the
myopathic forms, etc., are examples of this kind.

The integument of the atrophied members has a shrivelled,
purplish appearance, and the finger nails lose their pinkish
tint. Other trophic disturbances, except in atrophies due to
a neuritis, are wanting.

In many cases a fibrillary contraction, wave-like in appear-
ance, propogated in the direction of the fibers may be ob-
served occurring either spontaneously or by gently tapping
the muscle. This fibrillation, as it is termed, is of short
duration, returns after an interval of a few seconds, may be
limited to a muscle, or part of a muscle, or may extend over
the whole of the affected part or member. It is not pathog-

242 William Christopher Krauss

nomonic of progressive muscular atrophy, as was formerly
supposed, but has been observed in other affections of the
muscular system, and even in the healthy muscle.

Loss of Myotatic Irritability. Tapping a healthy muscle
produces a slight contraction of the fibers, which calls forth
the performance of its function. In the diseased muscle the
reflex arc is broken, the centripetal-sensory path remaining
undisturbed, while the centrifugal-motor path is broken.
The loss of tendon reflexes, in some forms, occurs quite early,
even before any serious damage has taken place in the mus-
cular fibers. The patellar and elbow reflexes are the ones
most generally tested.*

Electrical Trritability.-To Duchenne (de Boulogne) must
be given the credit of having first employed electricity asa
diagnostic and therapeutic agent. His method of localizing
the electrical current, published in 1850, has served as the
foundation for all later electrical researches in medicine. The
elder Remak appeared against him, disputing some of his
conclusions, particularly as to whether the contraction of the
muscle was produced by irritating the bulk of the muscle, or
the entrance of the motor nerve into the muscle. Von Ziems-
sen, taking advantage of this breach, made experiments upon
dying patients, and, by careful dissection afterward, discov-
ered that the motor points were those points where the motor
nerve approached nearest the surface (1857). The natural
law of muscular contraction under the influence of the gal-
vanic or faradic current, shows the superiority of the cathode
over the anode, the contractions being short, sharp and
quick. ‘The wasted muscle presents changes of electrical irri-
tability dependent upon the degree and extent of the degener-
ation. Erb and V. Ziemssen conducted a series of experi-
ments upon diseased muscles, and arrived at practically the
same conclusions at exactly the same time—1868.

Their law, called the Extartungs Reaction, reaction of de-
generation, is as follows: First degree, or partial reaction ;

* See author’s paper on Tendon Reflexes, Buffalo Medical and Surgi-
cal Journal, December, 1892.

Muscular Atrophy Considered as a Symptom 243

faradic and galvanic nerve irritability preserved, but weak-
ened ; faradic and galvanic muscle irritability preserved, but
the contractions, instead of being short, sharp and quick, are
slow and vermiform. In the second degree, or complete de-
generative reaction, the galvanic and faradic nerve irritability
and faradic muscle irritability are lost, but the galvanic muscle
irritability is increased. The action of the poles is, however,
reversed, the anode closure contraction being greater than the
cathode closure, and thirdly, the contractions are slow and
vermiform. In the third degree, or severe type, there is entire
loss of galvanic and faradic nerve and muscle irritability.
Any one of these three degrees may be present, according to
the seat and character of the primary lesion. Of these symp-
toms, the wasting and weakness are the only ones which are
truly pathognomonic. ‘The others, which are characteristic,
are present in some forms of muscular atrophy, and absent in
others.

Diagnosis.—To diagnose a case correctly, two essentials are
necessary: First, a thorough knowledge of the symptoms,
and second, a good working classification in which each par-
ticular variety has its only and proper place. One of the best
lessons taught us by our esteemed teacher whom we delight
to honor to-day, was to properly classify and arrange all facts
so that they could be most readily consulted. If this is good
practice in the scientific laboratory, it certainly must apply to
the human laboratory with even greater force. The study of
the tumors was vague and unscientific until Virchow proposed
his peerless classification. Charcot’s classification of the dif-
ferent forms and symptoms of hysteria has brought order out
of chaos, and the study of hysterical affections is to-day more
advanced and scientific than many of the longer recognized dis-
eases. Therefore, I hold that to be able to diagnose correctly
the different forms of muscular atrophy, symptomatically con-
sidered, one must have at command a classification based
upon the underlying pathology. A classification which has
served me well, was described by mein the Buffalo Medical
and Surgical Journal for April, 1891, and is here appended,
with but one or two slight changes.

244 William Christopher Krauss

Aplasia.
[ Developmental. { Hepeplasiat
Active. 4 Senile Wasting.
{ Diminished Nutrition.
Physio- 4 Passive. | Defective Assimilation.
logical. ee Processes.

(Dire Traumatism, etc.
Anchyloses.
pune, {gure Appliances.
Hysterical Contractures, etc.
Spontanic, Secondary, Traumatic, etc,
Toxic.
Neuropathic. Infective Processes.
Arthritic.

Scapulo-Humeral. (Erh’s Juvenile Form.)
Facio-Scapulo-Humeral. (Landouzy-
Dejerine.

Paralysis Pseudo-Hypertrophic.

MUSCULAR dies {Fotiomyeitis acuta Infantilis.

Myopathic.

Poliomyelitis acuta Adultorum,
ATROPHY. Hand ‘Type. (Du-
chenne-Aran.
Peroneal Type.
(Charcot-Tooth,)
Amyotrophic Lateral
Sclerosis.

Myelopathic. | Syrin lia.
Chronic. { Whe.

Patho- J Protopathic.
logical.

Heatenonee Gliomatous Growths.
thic. Locomotor Ataxia.
Multiple Sclerosis.
Diffuse Myelitis.
l a Mee Myelitis, etc.
: i onoplegia
ares { cerebral Patsies. Hemiplegia
L : Diplegia.

The different forms of developmental defects have been suf-
ficiently considered in another part of this paper. Under the
head of physiological atrophies are placed two forms, the
active and the passive. With the active atrophy is classed
senile wasting or the retrogression of old age. This form is
more or less general, affects all organs and tissues and has but
one termination, the result of all decay—death.

Belonging to the passive atrophies, or those processes which
are the result of disorders of the constructive organs may be
mentioned the wasting of the tissues following diminished
nutrition, defective assimilation, febrile processes, constitu-
tional diseases, malignant growths, etc. The atrophy is gen-
eral, attacks no particular group of muscles, tissue waste is
greater than tissue repair, and the atrophy continues until a
reaction sets in when the primary affection either goes on to
recovery or to a fatal termination. The diagnosis of this
group issimply the diagnosis of the fundamental disease. No

Muscular Atrophy Considered as a Symptom 245

attempt need be made to treat the functional atrophies fer se,
as in the great majority of cases they are passive, dependent
upon disorders of the system, which when relieved permit the
atrophies to disappear.

Pathological atrophies are either atrophy of inaction,
(functio lesio) or tropho-neurotic. The former can hardly be
classed as pathological, less physiological. They result when
the functional activity of the cells is interfered with, and the
nutritive changes are therefore diminished or abolished. As
a result the member grows smaller and weaker and continues
so until the cells regain their normal activity. Under this
head we meet atrophies due to anchyloses, surgical appliances,
hysterical contractures, etc. I have seen the arm reduced to
skin and bone incases of hysterical contracture, and, although
the rest of the body was well nourished and developed, still
the unused extremity was ina state of extreme atrophy. It
is a simple matter to diagnose such muscular wasting because
it is local, the cause is so very apparent and symptoms
pointing to complication are generally absent. No patho-
logical lesion can be found except a diminution in the bulk of
the muscle fibers. The treatment of these cases is very satis-
factory. ;

The tropho-neurotic atrophies are pathological and their
causes may be sought for insome disturbance along the course
of the peripheral nerves, spinal cord, brain or muscles. These
atrophies have a distinct and clearly definable pathology, and
are accompanied by symptoms indicative of an organic lesion
permitting of accurate diagnosis.

Neuropathic Atrophies.—Inflammatory conditions of the
peripheral nerves are productive of muscular wasting along
the course of the nerves. This class of atrophies may be
termed neuritic or neuropathic. If the atrophy follows a neu-
ritis, as in acute simple neuritis, multiple neuritis, endemic
neuritis, hemiatrophia-facialis, or a neuritis consequent to
trauma, pressure, chemical or thermal irritation, or secondary
to some inflammation of a neighboring organ, it is always

accompanied by the general symptoms characteristic of nerve
inflammation.

246 William Christopher Krauss

Toxic Atrophies. Agents which have been instrumental
in setting up a neuritic process and a consequent wasting of
the muscles are—alcohol, lead, arsenic, mercury and bisul-
phide of carbon. ‘The atrophy is generally limited to the ex-
tensor muscles, as seen in alcoholic paralysis, lead palsy,
arsenical pseudo-tabes, and on eliminating the poison from the
system, the atrophy sometimes disappears.

After Infective Processes. Following upon an acute attack
of diphtheria, variola, typhoid, typhus, cerebro-spinal menin-
gitis, etc., atrophic changes may take place in some of the
muscles of the body. ‘The lesion is generally neuritic, the
atrophy either the simple or hyaline degenerative, the latter
especially in typhoid, variola and cerebro-spinal meningitis.
In typhoid fever, typical hyaline degeneration of the rectus
abdominis and adductors of the thigh may frequently be met
with.

Arthritic Atrophies. Following injury to joints, atrophy
of the muscles moving that joint, but more especially the ex-
tensors, is often observed. If the hip joint is the seat of in-
jury, there is atrophy of the glutei; if the knee, the rectus
femoris ; if the ankle, the gastrocnemius and soleus. The
wasting is quite often pronounced and persistent, with little,
if any changein the electrical irritability, and increased tendon
reflexes. Theseat of the lesion is purely hypothetical. Vul-
pian, Charcot and others believe that the articular centripetal
nerves convey the irritation to the gray matter and particularly
to the motor cells of the ventral cornua, thence to the mus-
cles of the joint through the efferent nerves.

The diagnosis of these neuritic atrophies is not difficult in-
asmuch as they are always accompanied by pain over the
course of the nerves, trophic and vasomotor disturbances. The
wasting is local, limited, generally of a severe type with
marked electrical reactions, and, being dependent upon a
neuritic process, generally subsides upon cessation of the in-
flammation.

Of late there seems to bea disposition to classify another
form of muscular atrophy under this head, namely, the pero-
neal type, commonly called the Charcot-Tooth type. Erb and

Muscular Atrophy Considered as a Symptom 247

Hoffman have recently published cases in which neuritic
symptoms were present, such as sensory disturbances, marked
electrical reactions, local distribution, appearance after in-
fectious diseases, etc. Hoffman believes that this neuritis is
secondary to changes in the ventral cornua. If this is really
the case I see no reason why this type of atrophy should not
be considered under the myelopathic forms. Sachs who has
studied this form of atrophy very thoroughly, is disinclined
to accept Hoffman’s ideas as to its pathology and relegates it
to the spinal form of muscular atrophy.

The primary lesion in these neuropathic forms is to be
sought for in the nerves supplying the affected muscles. ‘The
neuritis may be either interstitial, parenchymatous or degen-
erative. In the interstitial form the medullary sheath is
broken into fine granules of fat and debrisand absorbed. The
axis cylinder is swollen, degenerated, and may be likewise
absorbed. The nuclei of the sheath of Schwann become
swollen and proliferate, leading to the formation of new con-
nective tissue, which, after the period of regeneration, consti-

248 William Christopher Krauss

tutes the bulk of the nerve fiber. ‘The perineurium and en-
doneurium also take part in this process and become converted
into thick layers of connective tissue.

The neuritic processes following the infectious diseases,
especially diphtheria, afford good examples of the parenchy-
matous form of neuritis. Fig. 3 shows the oculo-motorius
nerve in a case of diphtheria, the seat of marked degenerative
changes.* Many of the axis cylinders have disappeared, while
others are smaller and have lost their sharpness of contour.
The white substance of Schwann has absorbed the staining
fluid indicating some changes in regard to chemical com-
position.

In discussing the various forms of muscular atrophy, we
have only described diseases and conditions in which wasting
of the muscles was a prominent symptom not by any means
characteristic or pathognomonic. Other symptoms were always
present which denoted more forcibly than the atrophy the
seat of the disease or cause of the wasting. In the following
types the atrophy of the muscles is the predominant sign, so
much so that these affections have been designated pro-
gressive muscular atrophy and progressive muscular dys-
trophy.

Myopathic Atrophies.—The myopathic forms of muscular
atrophy are universally designated as progressive muscular
dystrophy, after the recommendation of Erb of Heidelberg.
They include several analogous types clinically and perhaps
pathologically, although the focal lesion has not been ulti-
mately determined. ‘They develop in the young, are relative-
ly rare and as yet the exact pathology is undetermined. Erb
is of the opinion, recently expressed, that there may be some
slight changes in the ventral cornua as yet undiscovered, and
that the myositis or lipomatosis is really secondary to organic
changes in the nervous system.

Erb’s juvenile form is the most prominent type of the

* See Author’s paper on Diphtheritic Paralysis in Neurologisches Cen-
tralblatt, No. 17, 1888.

SE =

Muscular Atrophy Considered as a Symptom 249

myopathic forms of muscular atrophy. It usually begins in
the muscles about the shoulder girdle, upper arm and back.
The pectoralis major and minor, biceps, brachialis anticus,
supinator longus, serratus magnus, rhomboidei, trapezius,
sacrolumbalis, latissimus dorsi and longissimus dorsi are the
muscles most often atrophied. The sterno-cleido mastoid,
levator anguli scapulae, coracobrachialis, teres, deltoid,
supra and infraspinati, rectus abdominis and the small
muscles of the hand remain undisturbed. ‘The muscles of
the lower extremities which are at times affected are the
glutei, the quadriceps, the adductors, the peronei and the
tibialis anticus. The sartorius, gastrocnemius and soleus
remain as a rule unaffected. Occasionally hypertrophy of
some of the muscles is observed, notably the deltoid, in-
fraspinati, triceps, tensor fascii and muscles of the calf.

This type of atrophy affects several members of the same
family, appears generally before the twentieth year, and has
a decided preference for females. It is not accompanied by
fibrillary twitchings, reaction of degeneration is not present,
and the tendon reflexes are unimpaired.

Analogous to this type is the facio-scapulo-humeral type,
first described by Duchenne as the forme héréditaire; but
later more fuller and minutely by Landouzy and Dejerine, in
1885. The wasting of some of the muscles of the face and
hypertrophy of the lips gives a peculiar tapir-mouth appear-
ance to the patient, ‘‘ facies myopathique.’’ With this excep-
tion, this type of atrophy corresponds exactly with Erb’s form,
and is regarded by many as one and the same.

Another form is the pseudo-hypertrophic paralysis of Du-
chenne. Although hinted at years before by Bell, Meryon,
Oppenheimer and Partridge, it remained for Duchenne, in
1861, to interpret correctly its clinical importance and estab-
lish it firmly in our nosology. It is no doubt hereditary, and
occurs more frequently in boys than in girls. The important
symptoms are weakness in the muscles of the leg and back, a
waddling gait, an apparent increase in the size of the muscles of
the calf,and sometimes of the thigh and calf. Furthermore, there
is lumbar lordosis brought about by wasting of the muscles of

250 William Christopher Krauss

the back and extensors of the thigh, some contractures, and a
peculiar difficulty in rising from the ground. Repeated ex-
aminations of the nerves and cord have been unsuccessful, and
hence the inference that the muscle itself is the seat of the
lesion, although the notion is gaining ground that the real
lesion may be located in the nerve centers, perhaps in the
spinal cord.

To understand better the pathological changes occurring in
the muscles, it may be desirable to review briefly the histology
of amuscular fiber. A striated muscle is composed of a num-
ber of bundles, surrounded by a layer of areolar tissue, the
external perimysium. Each bundle or fasiculus, enveloped
by a thin, delicate membrane, the internal perimysium, is
composed of bundles of fibres, separated from each other by
a delicate connective tissue, the endomysium. ‘These fibers
are arranged parallel to each other, are from two to four centi-
meters in length, and are united either to the tendons or apo-
neuroses, or else connected with the adjacent fibers.

Each fiber is composed of a number of filaments or fibrillee,
inclosed in a transparent homogenous membrane, designated
by Bowman, the sarcolemma. In the mammalia, elongated
nuclei are present on the internal surface of this membrane.
The primitive fibers are cylindrical or prismatic in form,
about sixty-five microus in breadth, and their length
depends not so much on the length of the muscle, as upon the
arrangement of the tendons. They are marked by transverse
and longitudinal lines or strize, giving them a characteristic,
striated or striped appearance. I will not take up the histo-
logy of the primitive fibrillee, but will limit myself to the
primitive fiber. (See Plate, fig. 1).

Each fiber has a vascular and nervous supply, the former
being furnished by the ramifications of the capillaries, run-
ning parallel between the fibers. The nervous supply is from
the moter nerves, and their termination in the muscle has
been the subject of much controversy. The motorial end-
plates of Kiithne or nerve hillocks of Doyére are generally
recognized by most recent observers. The nerve terminates
below the sarcolemma, where the medullary sheath becomes

Muscular Atrophy Considered as a Symptom 251

blended with it, forming a plate or plaque which is raised
somewhat from the fibers, but never encircles it. The axis
cylinder is distributed to this plaque, but does not penetrate
the interior of the fiber. The origin of the efferent or senso-
ry nerve fibers in the muscle is still a matter of uncertainty.

Fatty infiltration and degeneration of the muscular fiber, as
occurring in the myopathic form of atrophy has been desig-
nated as myositis or lipomatosis. Here hyperplasia of the in-
terstitial connective tissue and fatty infiltration follow closely
upon the wasting of the muscle, and cause either no apparent
change or else a slight increase in its volume. The muscle
appears pale, yellowish, has a greasy feel, and resembles
closely, not only macroscopically, but also microscopically, a
lipoma, or, better, a myo-lipoma. Under the microscope, the
large, round, yellowish cells, with dark borders, make up the
greater portion of the tissue. Here and there a muscular
fiber, with its transverse and longitudinal striation still intact
may be observed. (See Plate, fig. 3.)

The interstitial connective tissue is much increased in vol-
ume, with proliferation of its nuclei. The substitution of fat
may be so pronounced as to give the muscle an hypertrophied
appearance, and hence the denomination pseudo-hypertrophy,
given this affection by Duchenne in 1861. In some forms of
dystrophia, the muscular fiber may be even increased in vol-
ume, giving rise to real hypertrophy, a condition sometimes
met with in idiopathic muscular atrophy.

Myelopathic Atrophies, or Atrophies dependent upon Lesions
in the Spinal Cord.—They may be acute or chronic. The
acute forms are poliomyelitis acuta infantilis (infantile para-
lysis) and poliomyelitis acuta adultorum. Although not con-
clusively proven, still it is generally supposed that the onset
of this type of inflammation is due to some infection. Cases
are very common, both in the infantile and adult forms, where
an infectious disease preceded the attack. I have reported a
case occurring in aman forty-three years of age where the
poliomyelitis was undoubtedly the result of measles.

The acute stage is ushered in by general malaise, headaches,
pains in the back and limbs, fever, rapid pulse, somnolence,

252 William Christopher Krauss

delirum, convulsions, and in a short space of time a general
or partial paralysis sets in. After the decadence of the acute
stage, the paralysis confines itself to one, rarely several, of
the extremities. The muscles waste rapidly and show degen-
erative electrical reactions, the tendon reflexes are absent,
trophic changes are present, but no disorder of sensation. If
one of the legs be affected, the gait becomes very characteris-
tic owing to the atrophy and weakening of the peroneal
muscles. ‘The patient is obliged to throw the foot far for-
ward, the toes striking the ground first. Charcot calls these
patients ‘‘steppeurs.”’

In the adult form the disease is not so liable to recede and
the affected members remain often permanently powerless.

The chronic forms comprise most of the chronic affections
of the cord. ‘They are divided by Charcot, according to the
seat of the lesion, into protopathic, where the lesions are
solely and alone in the gray matter ; and deuteropathic, where
the gray matter is only secondarily affected. Under the first
head we have the Duchenne-Aran, or hand type, character-
ized by wasting beginning in the small muscles of the hand,
as the interossei, superficial and deep muscles of the thenar
and hypothenar, then extending to the flexors and extensors
of the fingers, biceps, brachialis anticus, supinator longus,
pectoralis major, trapezius, infraspinatus, supraspinatus,
rhomboid, serratus magnus, latissimus dorsi and sometimes,
though rarely, the flexors and extensors of the hip. The ten-
don reflexes are absent, fibrillary twitchings and altered elec-
trical reactions are present. There are no symptoms indica-
tive of trophic changes or disorders of sensation. This type
of atrophy is the original form of progressive muscular
atrophy described by Duchenne and Aran in 1848 and 1850.

In 1886 there appeared simultaneously from Charcot and
Marie in France, and Tooth in England, the description of an-
other form of atrophy. Its mode of onset is by attacking the
muscles of the lower extremities, the extensors of the toes
and the small muscles of the feet. Asa result there develops
a double club foot which is quite characteristic of this type.
The peronei, the calf muscles and later on the muscles of the

Muscular Atrophy Considered as a Symptom 253

thigh become affected. The muscles of the hand and fore-
arm may become involved after a lapse of years, producing
the peculiar ‘‘main en griffe’’ so characteristic of the Du-
chenne-Aran type. ‘This form of atrophy begins as a rule in
early life, isa family disease, attacks and progresses uniformly
on both sides, produces a double club foot, is attended at
times with slight disturbances of sensation and vasomotor
changes, and retains the tendon reflexes to a late stage.

The pathology of these forms has been the subject of long
and earnest controversy. The peripheral or myopathic origin
was stubbornly held by Friedreich and the German school,
while Cruveilhier, Charcot, Lockhart Clarke and others clung
to the central or spinal origin theory. The latter is now the
one universally accepted.

The ventral cornua of gray matter present the results of a
subacute inflammatory process leading to complete or partial
destruction of the ganglion cells, sclerotic changes in the
neuroglia, blood-vessel changes, cell proliferation, etc. The
contraction of the newly formed connective tissue may even
lead to the formation of cavities in the gray matter. (See
Plate, fig. 4.) The ventral spinal roots are affected second-
arily, likewise some of the efferent nerve fibres. Charcot’s
theory, then, is as follows: Atrophy of the muscular fibers is
the direct result of irritation, which, beginning in the gang-
lion cells of the ventral cornua, is propagated through the
ventral spinal roots and efferent nerves to the muscular fiber,
Friedreich’s theory was that the primary insult was a myositis
with secondary changes as ascending neuritis of the peripheral
nerve trunks, which terminated in a chronic myelitis.

The pathology of the Charcot-Tooth or peroneal type is still
sub judice. Woffman of Heidelberg has studied this form very
carefully and has declared it to be of neuritic origin. He,
therefore, has proposed to designate it ‘‘ progressive neurotic
muscular atrophy.’ Other observers still cling to the spinal
theory, and until definitely proven by careful microscopical
examination that it is primarily a disease of the peripheral
nerves it may be classed among the atrophies of spinal origin.

I have under observation a case of this type of atrophy in

254 William Christopher Krauss

which all the symptoms point to disease of the ventral cornua
of the spinalcord. Sensory disturbances and vasomotor troub-
les, symptoms of neuritic processes, are entirely wanting.

The pathological changes found in the atrophied muscles
in the myelopathic forms correspond to simple degenerative
atrophy. ‘To the naked eye there is little to be seen save the
diminution in size, and the pale, pinkish hue of the fibers;
to the touch, a soft, spongy feel, with occasional cord-like
prominences, instead of a firm, resistant mass. ‘The entire
muscle, if carefully removed, will be found shorter than nor-
mal owing to the contraction of the interstitial connective
tissue. Under the microscope the condition is as follows: If
the atrophy is not too far advanced, the fibers retain their
normal appearance —transverse and longitudinal striation—
but are somewhat narrower. As the process advances, the
fibers split up into longitudinal fibrillee, or transversely into
discoid masses and then gradually disappear. In other cases
fatty and vitreous degeneration may occur, and the fiber then
has the appearance of a sheath containing a clear material
with some fat globules. The intensity of this process is not
the same throughout the muscle, patches of healthy fibers
may be found surrounded by others in different stages of
atrophy. Proliferative changes occur in the nuclei of the
muscular fibers, and may lead to a new cell growth within
the sarcolemma, replacing the contractile substance. Prolif-
eration of the interstitial tissue also occurs and to such an ex-
tent as to separate the neighboring fibers, ‘The entire muscle
may, in fact, be converted into bands of connective tissue
with some fat globules interposed between the separate layers.
(See Plate, fig. 2.)

The true designation of muscular atrophy considered asa
morbid entity applies only to those affections in which pro-
gressive wasting of the muscles is the reigning symptom. As
such Erb’s juvenile form may be taken as a type of those
atrophies in which no focal lesion has as yet been discovered
in the nerve centers, but the muscle has been regarded as the
seat of the disease. As varieties, or deviations, may be men-
tioned the facio-scapulo-humeral type of Landouzy and De-
jerine, and the pseudo-hypertrophic paralysis of Duchenne.

Muscular Atrophy Considered as a Symptom 255

Secondly, those forms of myopathy due to a chronic anterior
poliomyelitis such as the Duchenne-Aran or hand type and
perhaps the Charcot Tooth or peroneal type.

The deuteropathic form comprises those affections in which
the involvement of the gray matter of the cordissecondary. The
atrophy following may be quite pronounced as in amyotrophic
lateral sclerosis, syringomyelia, and bulbar paralysis. A care-
ful examination is necessary at times to distinguish between
the atrophy of these affections and progressive muscular atro-
phy ; especially is this true of amyotrophic lateral sclerosis
and syringomyelia. These affections stand in close relation
to progressive muscular atrophy clinically and pathologically ;
nevertheless they can be diagnosed by symptoms which are
more or less pathognomonic. Inamyotrophic lateral sclerosis
the atrophy affects the muscles of the hand, arm, shoulder
and back simulating closely the Duchenne-Aran type of mus-
cular atrophy. In exceptional cases the lower limbs become
implicated. Contractures develop especially in the terminal
stage. The tendon reflexes are markedly exaggerated, loco-
motion is difficult and, what is very characteristic, the disease
runs its course in two to three years. In regard to the dura-
tion and course of progressive muscular atrophy and amyo-
trophic lateral sclerosis there is difference enough to convince
any observer that the two affections are distinct from each
other. In regard to syringomyelia, although the atrophy re-
sembles the distribution in the Duchenne-Aran type, still it is
not so uniformly advanced on both sides, and the sensory and
trophic disturbances which are always present enable one to
make a differential diagnosis. In bulbar paralysis the focal
lesion is of the same general character as in progressive mus-
cular atrophy, but limited to the ganglion cells in the medulla
and pons. Atrophy of the parts innervated by the cranial
nerves will be the result ; in rare cases this process may ex-
tend caudad affecting the ganglia of the spinal nerves.

In locomotor ataxia, multiple sclerosis, neoplasms of the
cord, diffuse myelitis and myelo-myelitis, the atrophy is less
pronounced, inconstant, and variable in its seat and intensity.

Lastly, cerebropathic atrophies, generally observed in the

256 William Christopher Krauss

spastic paralysis of children and adults. The atrophy is lim-
ited to the paralyzed members, as in monoplegia, hemiplegia
and diplegia. In the majority of these cases the atrophy is
slight, due more to the inactivity of the paralyzed member.
The reaction formula is normal, sensory disturbances are ab-
sent. In exceptional cases a high degree of atrophy may be
present due in all probability, not to the functio lesio, but to
the lesions in the trophic centers of the cortex, the exact seat
of which is as yet undetermined.

BUFFALO, N. Y.
JuLy 1893.

ILLUSTRATION OF MUSCULAR ATROPHIES—KRAUSS.

EXPLANATION OF PLATE.*

Fic. I. Cross-section of anormal muscle. Zeiss’ E objective, No. 1
eyepiece.

Fic. II. Simple degenerative atrophy of a muscular fiber. Zeiss E,
No. I eyepiece.

Fic. III. Fatty infiltration and degeneration of a muscular fiber.
Zeiss E, No. I eyepiece.

Fic. IV. Destruction of the antero-lateral group of ganglion cells,
ventral-cornua gray matter, spinal cord. The ganglion cells to the left
(antero-median) are intact, while the antero-lateral have been replaced
by cicatricial tissue. Zeiss E, No. 1.

* See author’s paper on Muscular Atrophies, Buffalo Medical and Surgical Journal,
April, 1891.

Sp IPs GAGs.

THE BRAIN OF DIEMYCTYLUS VIRIDESCENS,
FROM LARVAL TO ADULT LIFE AND COMPARI-
SONS WITH THE BRAIN OF AMIA AND PETRO-

MYZON.
SUSANNA PHELPS GAGE.

The remarkable changes in habits, appearance, structure
and physiology which occur at two distinct crises in the life
history of Diemyctylus viridescens, Raf.,* suggest the ques-
tion whether any corresponding changes in the brain occur at
these periods. Part I is a partial answer to this question.

In order better to understand and homologize certain parts
and regions of the diemyctylus-brain comparisons were made
with the brain of amia and of larval lampreys. ‘The second
part of this article deals with these comparisons and the gen-
eral conclusions drawn from them.

PART I.

THE BRAIN OF DIEMYCTYLUS.

In order to answer the question stated above the brain ot
diemyctylus has been studied in its various stages of develop-
ment (16).t A few ova were prepared—effort was mainly di-
rected, however, to the stages following hatching ;—the very
young larve (Fig. 12); older gilled larvee which are half
grown and ready to transform ; the gill-less red form in three
stages of growth, and finally the adult viridescent form
(Fig. 11), male and female of various sizes.

The investigation has been confined almost exclusively to
parts which in larger brains can be studied more or less per-
fectly by macroscopic sections and dissections. The purely

* Spotted triton or newt, vermilion spotted salamander (16).
+ The numbers in parenthesis refer to the bibliography.

260 Susanna Phelps Gage

histological studies necessary for a complete investigation have

not been made.
METHODS.

As the brain is small—6-7 mm. long in the adult—only a
few general facts can be arrived at by its study as a whole.
The skull is extremely hard, and the removal of a fresh brain
is difficult, hence specimens in which bone was developed
were decalcified and sectioned through the entire head (17).

The specimens were killed by chloroform or strong alcohol,
put immediately into picric alcohol, hardened in 67 and 82
per cent. alcohol, dehydrated and cut in collodion. Heemat-
oxylin and a variety of carmine stains were used. The nerves
and larger nerve tracts are well marked, and in some series
the deep origin of nerves can be traced with great distinctness,
while the natural relation of parts to each other and to the
membranes is left undisturbed.

Only young larvee needed no decalcification. A few brains
were removed and prepared by a modification of Golgi’s
method. Embryos were hardened in Perenyi’s fluid after re-
moval from the egg capsule.

About 70 series of sections of the head were made. Groups
of three specimens agreeing as nearly as possible in size and
development, were cut in the three planes, transverse, sagittal
and frontal, in order to correct errors due to loss of substance
in cutting and to ensure the natural arrangement of parts in
drawing.

The photographic reproductions in Plate 1 show the char-
acter of the material, the eye only, of the macroscopic parts,
is imperfect, the lens being so hard that its removal was nec-
essary. Cilia, when present, were perfectly preserved in the
mouth and nasal cavities, but were not found within the brain
cavities. Whether this is due to their absence or the re-
tarded penetration of the hardening agents is not known ;
other details of structure are clear. ’

HISTORY.

The brain of diemyctylus has been little studied. Mason
(32) shows by a photographic process a transection through

The Brain of Diemyctylus Viridescens 261

the geminums and a fragment of the cerebrum to illus-
trate histological structure. Burckhardt (6) in compar-
ing the brain of Ichthyophis with Triton, bases his main con-
clusions upon the European forms of triton, but records a few
observations upon the American form, diemyctylus. His
adult material was hardened and decalcified in a mixture of
chromic and nitric acids and cut through the entire head.
His general conclusion with regard to the urodeles may be
summarized as follows (p. 400): They are uniform in the
non-existence of a neck-flexure, and in having a small pons-
flexure. The mesencephal appears like the myel in section.
The diencephal loses its connection with the epiphysis which
becomes functionless. The olfactory lobes are not distinct
from the cerebrum and the latter has no temporal lobe. The
double root of the olfactory nerve he considers of small phy-
logenetic moment. He considers that in this group a reci-
procity exists between the size of the united rhinen- and pros-
encephal and the united dien- and mesencephal. In the only
specific references to diemyctylus (p. 372), he says that the
two former equal in volume the two latter, that the mesence-
phal swells out into two corpora bigemina, and that, as in all
tritons, the mesencephal has a sulcus dorsalis (p. 377).
With regard to the general statements given above the obser-
vations in this article in the main agree. Neither of these
authors have touched upon the problem stated above, and
‘a number of matters are described and illustrated in this
article which have hitherto not been recorded.

A preliminary paper containing some of the points here
given was presented at the American Association for the
Advancement of Science (18).

BRAIN OF THE ADULT. PL. II-V.

In general outline and proportion of parts the brain of die-
myctylus differs little from the other urodeles as shown
by Osborn and others. The united hemicerebrums and olfac-
tory lobes form the most conspicuous part of the brain and
overlap the diencephal which with the mesencephal forms
a rounded body. This in turn overlaps the metencephal,

262 Susanna Phelps Gage

the cerebellum being nowhere visible from the surface. The
metaplexus forms a conspicuous object on the dorsal side.
The supraplexus is not very large and lies between the caudal
angles of the hemicerebrums ; immediately behind it are the
habenz and the small epiphysis. On the ventral side, the
diencephal with its connected infundibulum and hypophysis,
covers the floor of the mesencephal.

In the mesal view, the cerebellum appears ; the thickness
of the parietes, the relations of commissures, cavities and plex-
uses are also seen.

In the figures, interrupted lines indicate the extent of the
cavities which are wide, especially in the dorso-ventral direc-
tion, as seen in sections (Pl. III). The constrictions of the
cavities are so great, that sections, which like those of Pl. I
show them as continuous from cephalic to caudal extremity,
are rare.

Rhinencephal.—As in other urodeles the olfactory lobes
are entirely separate from each other. From the ectal surface
there is little appearance of constriction separating the olfac-
tory lobes from the hemicerebrums. ‘The cavities show a slight
dorso-lateral constriction (Fig. 5,) in frontal view seen in fig-
ure 37. A decided angle exists at the caudal boundary of
the rhinoccele (Fig. 35, 41), which corresponds almost precise-
ly with the caudal boundary of the second olfactory nerve
root. Hence it is seen that the rhinencephal is nearly equal
in length to the prosencephal.

The paraplexus intrudes slightly into the rhinoccele. The
extensive area occupied by the external origin of the olfactory
nerve roots is noticeable and the fact that a fold of pia in-
trudes between the two roots.

Cinerea covers nearly the entire surface of the olfactory
lobes. But it is a remarkable fact that at certain points the
ectal cinerea is continuous with the ental (Fig. 14-15, 35-37,
41) as though the embryonic condition were preserved.

Prosencephal.—The hemicerebrums have a decided though
short caudal projection (Fig. 19-22), beyond the portze, contain-
ing a spur of cinerea (Fig. 36, 42) which corresponds in position
with a similar spur which Edinger (11, p. 20) has found in rep-

The Brain of Diemyctylus Vtridescens 263

tiles. This he calls Ammon’s horn as it connects with
olfactory nerve fibers and represents the cortical olfactory cen-
ter of higher forms. Whether a similar connection and func-
tion can be demonstrated in diemyctylus is not known.

The paracceles open by wide porte into the aula (Fig. 17,
36, 37). ‘The cavity of the latter is nearly filled by a plexus,
auliplexus (p. 265), so that the portee are not visible from the
meson (Fig. 6).

The caudal limit of the aula is defined by a band of alba or
white matter rising from the floor of the brain, in the terma.
Thisis formed by the cerebral commissures. ‘The more dorsal
portion is the callosum (38, 42), which in the form of a horse-
shoe sends lateral columns dorsad (Fig. 6, 18, 19, 42, 51) into
the mesal walls of the hemicerebrums (Fig. 35-37)-

These mesal walls of the hemicerebrums as they bulge into the
cavity of the paracceles have sometimes been called striatums,
in amphibia. Osborn (38, Fig. 9) shows the fibers of the
callosum distributed in this region of the frog to ‘‘ the upper
median cell area,’’ while in reptiles and birds he found in this
region a ‘‘sulcus’’ or fissure, the hippocampal. Nakagawa
(35) considers the cells of this region in spelerpes to be a rudi-
mentary cortex. In diemyctylus this region is clearly defined,
contains numerous, but well separated cells in large peri-
cellular spaces (Fig. 41, ce.), extends from the rhinoccele to
the porte (Fig. 36) and caudad over the portze to near the tip
of the cerebrum (Fig. 21, 35). The fibers of the callosum
spread out between these cells. There is ‘no indication of a fis-
sure but it seems proper to use the term cadlosal eminence to in-
dicate this ridge pushing into the paraccele, as it corresponds
in position to that eminence as shown by Wilder (55, Fig.
4748) in a human fcetus.

In figures 17-19, 51, angles in the paracceles are seen asso-
ciated with projections of cinerea which form two horns curving
outward and toward each other. This enclosed, lateral region
of the cerebrum, through which the fibers of the precommissure
pass, may be considered as a very undeveloped form of s¢vzatum
—inasmuch as in other forms this region has been so homol-
ogized.

264 Susanna Phelps Gage

The precommissure, as seen upon the meson (Fig. 6), is
closely associated with the callosum, but a little distance on
either side three bands of alba appear (Fig. 51), the dorsal, the
callosum, the other two, parts of the precommissure (38).

Diencephal.—Caudad of these cerebral commissures and
partly underlying them is the preoptic recess (Fig. 18), aslight
pocket in the endyma of the terma, which is continuous cau-
dad with the small recesses extending slightly into the roots
of the optic nerves. The cinerea about these processes is
continuous in the center of the nerve-to its entrance into the
eye (Fig. 40), though no lumen is visible.

The chiasma (Fig. 6) projects into the diaccele and does not
project below the general level of the ventralsurface. Whether
the part marked chiasma also includes an inferior commissure
is not certain, but seems probable, as it has been found in
Triton alpestris and other urodeles.

The zzfundibular region is large as in other low forms, and
has wide lateral processes of the cavity which underlie the
saccus. ‘The saccus is formed by an irregular tubular arrange-
ment of cells, corresponding in appearance to the endymal cells
of the vicinity. The continuity with endymal cells is probable,
and isso represented in figure 23, but is not an absolutely
established fact. Among the tubules are capillaries. The
saccus is small in comparison with other amphibia and fishes
(cf. Fig. 93). In other series than those represented, no such
tubular arrangement was found, the roof of the infundibulum
being composed of a single, simple layer as though not thrown
into folds to form a saccus.

The hypophysis is distinctly tubular and appears to be en-
closed by pia which separates it from the infundibulum, as
Osborn (37, p. 264)found in Cryptobranchus. Pigment cells
from the dura are also seen to intrude between them in frontal
sections (Fig. 50). In one heavily pigmented specimen such
cells completely separate the hypophysis from the infundi-
bulum. The floor of the infundibulum dorsad of the hypo-
physis is wide and composed of asingle layer of endymal cells.
No indications of hypoaria as in fishes (Fig. 93) were found.

The thalamus (Fig. 19-22, 37-38) is not sharply defined

The Brain of Dientyctylus Viridescens 265

from the striatum; its endymal surface is marked by sulci,
one of which extends from the porta to the infundibulum—
another continues caudad as the widest part of the mesoccele,
another lies ventrad of the enlargement of the habena (Fig.
20-22).

The roof of the diencephal (Fig. 52) is separated caudad
from the mesencephal by the postcommissure. Cephalad of
this are, (1) the simple layer of endyma which underlies (2)
the epiphysis, (3) the supracommissure connecting the habenze
(Fig. 59-60), and (4) a layer of flattened cells passing ceph-
alo-ventrad from the supracommissure and reflected over the
diaplexus. This order agrees with that now usually accepted
and not with that mentioned by Edinger (10, p. 37)
which he places the connection of the epiphysis with the roof
cephalad of the supracommissure.

The epiphysis is insignificant (see p. 285). The supracom-
missure (Fig. 52) is traversed by processes of the endymal
cells covering it.

Plexuses.—The supraplexus is seen on the dorsal surface of
the brain (Fig. 4). It isa complicated coil of blood vessels
connected with the blood supply of most of the cephalic part
of the brain. Vessels lying in the intercerebral pia (Fig. 6, 7),
and vessels extending between the cerebrum and thalami
unite with it (Fig. 21), and from it are supplied the two plex-
uses entering the brain at this point. Within its coils lies the
paraphysis (Fig. 6, 52, 59), (see p. 286). The opening of
the paraphysis indicates the division between two plexuses
which are here named from the place at which they enter the
cavities the aw/iplexus and the dzaplexus, in preference to the
terms of Burckhardt (6). He calls the same things in Ich-
thyophis, superior, inferior and medius, making three divis-
ions instead of two.

Figure 6 shows these two plexuses from the meson. The dia-
plexus extends sometimes to the cerebellum or even farther,
or sometimes is found with its tip pressed close to the post-
commissure. Its blood supply is from the caudal side of the
opening of the paraphysis, while the auliplexus receives its
supply from the cephalic side (Fig. 7).. The latter at its en-

266 Susanna Phelps Gage

trance to the aula dips ventrad, separating the porte (Fig.
17), and gives off from its dorsal part the two paraplexuses
(Fig. 42) which extend even into the rhinocceles. Dorsad of
the callosum it is constricted but continues caudad into the
diaccele (Fig 22) where it becomes much expanded and falls
into the infundibulum.

Mesencephal.—There is no marked stricture between the
mesoccele and the diaccele though the postcommissure and
the origin of the 3d nerve may be considered as approximately
determining the division.

Ventrad of the postcommissure are seen cells differing in
character from any others of the endyma, having a wide clear
margin, and together forming in section, a lunular mass on.
either side (Fig. 59, 60, 9, 10). From these cells fibers appear
to take origin which become incorporated in the postcom-
missure. Sections prepared by the silver method were de-
fective in this region and hence proof of the connection of
the fibers with the cells is not positive.

In lamprey (Fig. 110), similar cells are found but the masses
are farther separated by the postcommissure. To the cells
similar in appearance, but underlying the habenz, Edinger
(10, p. 20) ascribes asecretory function, while Rabl-Ruckhard
(41) homologizes such cells in some amphibia, reptiles and
birds with the torus longitudinalis of bony fishes (see Fig.
100). In section, the mesencephal is oval with such a slight
depression on the dorsimeson (Fig. 25) as hardly to justify call-
ing it a sulcus, as does Burckhardt (see p. 261), and except for
uniformity the term geminums does not seem applicable. The
cavity is oval except at its caudal part (Fig. 26) where it be-
comes a mere slit. There is no special lateral expansion at
either cephalic or caudal part, and hence no indication, in the
adult of lateral recesses. ‘The dorsal union of the geminums
is wide, the cinerea occupying the ventral half, with more
scattered cells in the alba of the more dorsal portion. These
cells extend to the extreme dorsal limit, but only upon a mesal
plane: (Fig. (25, \\26); (see psiieg3).) (rom) theseseelisi¢iaa
cinerea extends on either side in three somewhat illy de-
fined concentric layers (Fig. 24-26) as Nakagawa (35) de-

The Brain of Diemyctylus Viridescens 267

scribes in Spelerpes, not in the clearly separated layers of
cinerea found in the frog (Osborn).

LE-pencephal.—Projecting far cephalad under the mesencephal
is seen the cerebellum, with bands of white matter crossing
the meson (Fig. 6, 26, 36, 37). The origin of the 4th nerve at
this point is the only indication of a valvada. Laterally the cere-
bellum is larger than on the meson (Fig. 26) and projects into
lateral recesses which are continuous with the metaccele. "The
origin of the 5th nerve from the floor of the recess indicates
that its more cephalic portion at least may be counted as
belonging to the epencephalic segment and perhaps it rep-
resents the lateral recess (parepiccele) of the epencephal of
higher forms.

Metencephal.—All of the nerve roots belonging to this seg-
ment from the 6th to the 12th, were found and their ectal
origin is indicated on figure 5. For a further consideration
see p. 273.

The metaplexus forming the roof of the segment is large,
and for convenience will be considered in two parts, as the
appearance changes. The cephalic part is wide and has a
mesal fold dipping into the metaccele. On either side of the
fold is a series of pockets lined by endyma and connected with
the metaccele (Fig. 27, 35). The pockets radiate from the
mesal fold of this portion of the plexus. A blood vessel lies
in the median fold, and connects with others between the
pockets. The spongy portion of the plexus thus formed is
bounded caudally by a spicule of bone which crosses the
meson (Fig. 6, 28). Ventrad of the bone and in the region
of the origin of the 1oth nerve, the dorsal walls of the meten-
cephal become approximated and the plexus narrow and sim-
ple (Fig. 28). This is a strong reminder of the fish-like con-
dition where in a corresponding region the walls touch or act-
ually unite across the meson (Fig. 93 of amia). The caudal
portion of the metaplexus extending from this point again
widens (Fig. 29), and retains its simple character. Just ceph-
alad of the closure of the myel, the endyma and pia of the
metaplexus are absent across the meson, thus forming a true
metapore (see p. 279).

268 Susanna Phelps Gage

Membranes.—The pia forms a complete investment for the
brain, but does not in all places follow the outline closely,
frequently lying nearer the dura than the brain (Fig. 16).
Between the hemicerebrums the two folds unite to form a single
membrane within which the blood vessels run (Fig. 19). The
pia invests the hypophysis separating it from infundibulum
(Fig. 6), and is continuous over the epiphysis (Fig. 22).
The blood vessels in the pia are numerous, as are also the capil-
laries penetrating the brain. ‘The latter usually enter the
brain and return by the same path (Fig. 51), thus forming a
close loop, which extends deep into the alba, as at the cal-
losum (Fig. 51). The capillaries extend to but not into the
entocinerea, passing between cells of an incipient ectocinerea
as in the olfactory lobes and the callosal eminence (Fig. 17).
Plate III shows the number and extent of the loops accurately.

Whenever the pia is separated from the brain, it is seen that
upon the surface of the latter nuclei indicating cells occur at
some little distance from one another, and that the surface is
clothed with filaments extending toward the pia (Fig. 51).
Stieda (47) found such filaments in the frog. Examination of
sections stained by Golgi’s method, from the mesencephal,
where this condition is clearly defined, shows that cells lie at
frequent intervals among the bases of these filaments (Fig. 61).
The cells give off processes extending at least to the cinerea,
while other cells scattered in the alba give off processes
toward the endymal cells. In some sections the processes
from two cells in these different situations unite or at least
touch. In the larve (Fig. 62) similar filaments are seen
bridging the space between the brain surface and the pia.

The arachnoid is represented by connective tissue cells lin-
ing the dura, and forming a spongework in the larger spaces
existing between the dura and pia, notably in the triangular
dorsal and ventral spaces existing between the pia of the two
hemicerebrums (Fig. 6, 14) ; in the large spaces laterad of the
mesencephal (Fig. 22), and in the region of the metapore
(Fig. 29).

The dura is a membrane, containing numerous large pig-
ment cells (Fig. 52, 55), lining the cranial cavity ; sending

The Brain of Diemyctylus Viridescens 269

off an almost complete investment for the supraplexus (Fig.
51, 53), a somewhat partial one for the hypophysis (Fig. 50,
23); filling a large space (Fig. 28) caudad of the more spongy
part of the metaplexus ; surrounding the protrusion of the
endolymphatic sacs into the cranial cavity (Fig. 8) ; following
out the nerves from the cranial cavity (Fig. 40, II) and sur-
rounding their ganglia (Fig. 24, 39).

The endolymphatic sacs (Fig. 8) unite by a tube with the ear,
appearing as Norris (36) has shown in amblystoma. They
extend cephalad each side of the mesencephal (Fig. 35-37,
23-27), with diverticulums passing caudad of the mesence-
phal approaching each other over the metaplexus where the
cavities of these sacs and of the brain are brought into very
close contact (Fig. 37). In one specimen the sacs unite
over the meson (Fig. 34) as they are said to in the frog. By
injection methods Rex (43) has studied the grosser vascular
supply of the brain of Zyiton cristatus, and as far as the die-
myctylus has been studied it agrees closely with his results.

Intermaxillary gland.—Cephalad of the brain, between the
nostrils, with its tubules very close to the nasal epithelium is
the intermaxillary gland with its duct opening into the mouth
between the choanz (Fig. 6, 35-40). Wiedersheim (49) at-
tributes the discovery of this gland to Leydig, and gives a
full account of it. In the urodeles it extends farther’ caudad
than in the anura, but he shows no such close apposition to the
brain as occurs in diemyctylus. Here the tubules ramify very
close to the brain not being separated from it by a bony
wall for some distance on either side of the meson. The com-
bined meninges in this situation are delicate. In fact its sepa-
tion from the brain is only slightly more pronounced than that
of the hypophysis. Its nervous supply is apparently from a
branch of the 5th which crosses the olfactory nerve (Fig. 41).
In young larvee the gland does not appear, but before the end
of the gilled larval stage it is well developed. In the red
forms it reaches its maximum development in correlation with
the greatly exaggerated glandular growths in the skin. In
this stage its greatest usefulness would be expected as the se-
cretion in other species is said to aid in securing food by mak-

270 Susanna Phelps Gage

ing the tongue viscid. In aquatic forms such a viscid secre-
tion naturally would not seem of much use, at least the ap-
pearance of the gland in the adult seems to justify this con-
clusion for its tubules are more shrunken and its cells have
less the appearance of activity. A further comparison of this
gland in the different groups of amphibia seems desirable.

BRAIN OF YOUNG LARV#. PL. I. VI, VII.

The larve, the brains of which are figured, were about 1
cm. long—were only a few days from the egg, had lost the
“‘balancers;’’ the eyes were large, the pectoral limbs formed;
they were active and responded promptly to any jar of the
water. Food was found in the stomach and a thoroughly in-
dependent existence was established.

The description of Plate I serves to compare the adult and
larval brain as seen in frontal section. A comparison of fig-
ures 4 and 64 shows the marked differences in external form.
The olfactory lobes and cerebrum together are relatively short,
and the cerebrum is overhung by the diencephal with the
habene. The united dien-and mesencephal form a more
marked feature of the brain; the mesencephal still farther
overlaps the metencephal ; large as the infundibular region is,
it is almost enclosed by the cephalic extension of the lateral
wings of the epencephal which project far laterad also (Fig.
64-65). In general the argreement of the larval diemyctylus
with amphiuma as described by Kingsley (30) is very close.

The cells composing the cinerea are much larger than in
the adult, and in many places are distinctly arranged in rows
radiating fromthe endyma (Pl. VII). This arrangement exists
in the adult (Fig. 51) but does not show with low magnifica-
tion. The alba of the larva is small in quantity relatively—
being massed at the sides—with a small amount crossing the
meson (Fig. 6, 67).

Rhinencephal.—The olfactory lobes are less separated from
the hemicerebrums than in the adult, though the caudal limit
of the former may be determined by the position of the second
olfactory nerve root which is present. Cinerea occupies a
large portion of the lobes and the continuity of ectal with
ental cinerea is extensive.

The Brain of Diemyctylus Viridescens 271

Prosencephal.—The cerebrum is markedly undeveloped,
especially in the region of the callosal eminence (compare
Fig. 35, 69; 36, 2; 37, 71; 16, 76). Owing to this the terma
and hence the porte have their cephalic boundary at a level
with the caudal portion of the olfactory lobes. ‘The lack of
development of the callosal eminence is correlated with the
fact that barely a trace of the callosum is seen (Fig. 91), a
few fibers appearing on each side and even fewer crossing the
meson. ‘The combined callosum and precommissure do not
rise much from the general level of the floor of the cavity
(Fig. 67). The precommissure is foreshadowed by the two
small white areas crossing the meson, while the striatum (Fig.
16, 78) shows one lamina of cinerea instead of two as in the
adult.

Diencephal.—The chiasma and optic nerves are well de-
veloped as would be expected from the condition of the eyes.

The infundibulum is much compressed cephalo-caudad and
no alba is developed in it (Fig. 81, 22). A saccus is not
formed, and the hypophysis is minute (Fig. 82). The roof of
the diencephal presents the same relations asin the adult, but
the opening between the supra- and postcommissures into the
epiphysis can be traced (Fig. 68). The epiphysis is relatively
larger than in the adult but its cavity is much depressed.

The habene are relatively very large (Fig. 4, 64), they ex-
tend far cephalad and partly overhang the paraphysis (Fig.
78, 91), and except for intervening pia they present a large
area upon the meson (Fig. 67).

Plexuses.--'The paraphysis is an almost straight tube with
an enlarged end (Fig. 67, 78, 79), surrounded by a few cells
and small vessels which constitute the rudimentary supraplex-
us, and have the same relation to the other plexuses as in the
adult (Fig. 66,67). The dia- and auliplexuses have the same
relative position and extent as in the adult, but the endyma
with which they are covered is undifferentiated from other
endyma and the contained blood vessels are minute. ‘The
paraplexuses arising from the auliplexus are small (Fig. 78),
and do not extend into the caudal part of the paracceles as in
the adult (Fig. 21).

272 Susanna Phelps Gage

Mesencephal.—This differs considerably from the adult.
From the dorsal aspect (Fig. 64) a broad band of cinerea is
visible, while in the adult only a very limited area at the cau-
dal end is seen (Fig. 4). Thisis part of the ental cinerea
which has not yet been covered by the growth of alba. The
cavity also differs in form, since at the caudal end a very wide
lateral expansion exists (Fig. 84) which later entirely disap-
pears (Fig. 26). This early character resembles the post-optic
expansion of the frog, reptiles and birds.

The middle and cephalic portion of the cavity (Fig. 81-
83), shows a narrow extension to the roof. The extent of
this narrow portion is shown by the more lightly shaded por-
tion of the mesoccele in figure 67. The roof in this part con-
sists of a single layer of endymal cells, but it is evident that
the closely approximated sides are in process of union. ‘This
process is complete in the adult, a mere trace of the past his-
tory being retained in the scattered cells which hold their
place in the alba (Fig. 26).

E:pencephal.—The cerebellum upon the meson is very small
(Fig. 67) and shows only a trace of alba (Fig. 84), yet lat-
erad it is larger (Fig. 83). ‘The lateral recesses of the epiccele
extend far cephalad. The relations of the cavity and the 5th
nerve shown in figure 82 seem to confirm the conclusion that
this cavity with its lateral recesses must be assigned to this
segment rather than to the metencephal, though the relations
are more obscure in the adult. The lateral wing of cinerea
seen (Fig. 25) in the adult apparently indicates the partial
closure of the cephalic portion of the epiccele. Figures by
Herrick (24) of the sturgeon’s brain in this region show clear-
ly the relations which in amphibia are very obscure, and are
confirmatory of the above conclusion.

Metencephal.—From the dorsal side, this segment shows a
broad band of cinerea (Fig. 64) upon either side of the plexus.
This almost disappears in the adult (Fig. 4).

The metaplexus is wholly undifferentiated being formed of
a simple layer of cells not much different from the other endy-
mal cells, and over it a few mesodermal cells which probably
belong to the pia (Fig. 86-88). There is no indication of a
metapore.

The Brain of Diemyctylus Viridescens 273

Membranes.—The pia is a very delicate membrane, in many
places clinging closely tothe dura. Its relations are the same,
as far as traced, as in the adult, it supplies comparatively very
few blood vessels to the brain; a few in the olfactory region
(Fig. 75); in the region between the mesen- and epencephal
(Fig. 82); and to the medulla (Fig. 85). Contrast the capil-
laries of Plates III and IV with VII.

The arachnoid is represented by a few connective tissue
cells, and can be clearly seen only in the cephalic region in
the triangular spaces between pia and dura (Fig. 75).

The dura is thin, and in the dorsal part where the cartilage
of the skull is not developed, lies in close contact with the epi-
dermis. In this part a few pigment cells exist.

The endolymphatic sacs are slightly developed and appear
in only a few sections (Fig. 83, 84), they are closely applied to
the lateral recesses of the epiccele but do not extend over the
metaplexus. The canal connects it with the ear more directly
than in the adult.

Nerves.—The methods, as stated, are not especially adapted
to the study of nerve tracts, hence little beyond the external
origin is mentioned. The relations in the larve are often
clearer than in the adult.

I. The olfactory nerve in both young and adult has two
lateral roots; in the latter a whorl-like arrangement of cells
is seen in the lobe and more proximal part of the roots, that
is not present in the larva. The roots unite to form one
trunk which divides, sending branches to surround the nasal
epithelium and to Jacobson’s organ. These observations
agree with Burckhardt (6) rather than with Kingsley (30),
who found only one root in larval amphiuma.

II. The optic nerve is similar in larva and adult; the
central cells of the larva occupy a much larger proportion of
the nerve. In both, at the exit from the brain there are no
fibers on the dorsal side of the nerve (Fig. 20); the fibers
twist dorsad and soon form a complete tubular investment for
the cells. The chiasma is well developed.

III. As shown in figures 23, 44, 38, 81, this has the usual
place of origin. Inthe larva the commissure across the meson
is cut off from other alba by cinerea (Fig. 67).

274 Susanna Phelps Gage

IV. Though small in the adult, this nerve is clearly seen
(Fig. 26). Inthe larva a few cells (Fig. 84), probably indi-
cate its rudiment, for in the next older stages it can be found.
In the adult, the 3d and 4th nerves escape from the skull by
separate forameus (Fig. 3). In the larva only one foramen
through the cartilage is seen, and through this the 3d leaves
the brain. Kingsley (30) did not find this nerve in larval am-
phiuma.

V. This has its origin at the usual place ventrad of the
lateral recess of the epencephal (Fig. 39, 40, 25). Figure 44
shows fibers arising near the origin of the 3d, which extend
to and unite with the fibers of the 5th. In the larva this
nerve and the lateral recesses are far cephalad (Fig. 6, 82).

VI. The origin of this nerve is caudad of the 8th and upon
the ventral side (Fig. 63). It is very small even in the adult
(Fig. 25), but can be traced latero-cephalad to its union with
the gasserian ganglion. In the larva only a mere trace of it
was distinguished (Fig. 85) at its origin. This nerve is in
amphibia so small as to escape observation, or it is variable in
position. Kingsley (30) says it is not found in larval am-
phiuma; Reissner (42) shows it in the frog; Ecker (9, p.
149) figures it at the level of the 1oth in the frog ; Fischer (13)
in siredon near the 7th; Osborn omits it entirely from some
of his figures.

VII, VIII. In the adult these two nerves are very closely
connected, as are their ganglia. The 8th, however can be
said to be cephalo-ventrad of the 7th at its origin (Fig. 3-5),
and comprises fibers only (Fig. 26), some of which cross the
meson, ‘The 7th at its origin has a great dorso-ventral
extent, the more dorsal part extends from the sulcus (p. 291)
(Rautenlippe of His), existing between the solid and mem-
branous portion of the metencephal, and is cellular in character.
The more ventral part consists of fibers (Fig. 8). There is no
space between the fibers of the 7th and 8th, which pass
into the united ganglion. In the larva the origin of the 7th
and 8th are quite separate; the cellular portion of the 7th
is continuous with the cinerea about the sulcus on
the one hand and the ganglion on the other; while the

The Brain of Diemyctylus Viridescens 275

ganglia of the 7th and 8th are distinct (Fig. 83, 84, 92), the
latter being more ventrad. In the adult, from the 7th a
branch extends to the gasserian ganglion (Fig. 3, 4), and
from the united ganglion a branch, said to be a part of the 7th,
extends through the cephalic part of the ear, and branches
are distributed to the sensory epithelium of the ear (Fig. 40).
The observations recorded seem to agree with Ayers’ studies
(2). Strong (48) says that in amblystoma a branch of the 7th
which innervates the lateral line, disappears when the animal
adopts a terrestrial life. In diemyctylus, with the return to
aquatic life, in the adult male, pockets are formed at the side
of the head (Fig. 40, II) which receive branches of the 7th.
There has not been time to study the changes of the nerve in-
volved, but it is possible that here is a fruitful line of work
upon the post-embryonic changes in a nerve.

Gasserian ganglion. In the adult two branches of the 5th
and a branch of the 7th can be traced into and through this
ganglion which lies within the skull and close to the endolym-
phatic sac (Fig. 3, 23,39). Inthe larva the ganglion is deeply
lobed (Fig. 63), the two cephalic portions are connected with
branches of the 5th, the more caudal with the branch of the
7th.

IX, X, XI, XII. (Fig. 5, 65). The ectal origins of these
nerves form a series each arising at a more ventral level than
the preceding. The goth is associated with a sulcus at the
dorsal edge of the medulla, and the t1oth with a more
ventrally placed extension of cells, which according to
His (26) would represent another sulcus which has been
obscured by growth. This is clearly seen in the larva (Fig.
86). In the adult the 11th is seen to be an offshoot from
a deep-lying bundle of fibers arising in the myel, part of
which pass to the 11th and part extend further cephalad as the
solitary bundle (Fig. 43). The origin of the 12th is far ventrad
(Fig. 88). In the larva is an indication of a dorsal root (x
in Fig. 65), such as is mentioned by Kingsley in amphiuma
(30) and Froriep (14) in an embryo ruminant.

276 Susanna Phelps Gage
THE BRAIN IN EMBRYOS.

The incubation of ova in the laboratory lasted about one
month. Within seven days, the optic and otic vesicles are
formed. At twelve days the eyes, lens and rudiment of a
nasal pit are formed and the brain in reconstructed mesal view
agrees well with a figure of a newt shown by Misses Johnson
and Sheldon (29). The partition between the prosen- and
diencephal is formed and from this extends the dorsal division
between the hemicerebrums. At fifteen days a protuberance of
the diencephal (epiphysis) is formed and the infundibular re-
gion is partially constricted. No alba has appeared, the walls
being purely cellular. A mesal view is similar to one by His
(27) of Ambhystoma punctatum. At or near the time of
hatching the eyes are large; the muscular development is ex-
cellent and suited to the quick darting motions. ‘The yolk sac
is large and the mouth not yet perforated. Balancers exist
and the nasal pit is formed. The cephalic curvature still re-
mains so that a transection in the cephalic region still shows
the structures found in frontal sections of older forms. The
united cerebrum and olfactory lobes are short, extend ventrad
from the diencephal, which with the mesencephal forms the
most cephalic and the most prominent portion of the brain.
In the wall between the hemicerebrums, is the rudiment of the
paraphysis (Fig. 73) and into the diaccele projects a rudiment
of the diaplexus. In figure 74 the aula is seen to reach
nearly to the tip of the rhinencephal. The mesoccele is a wide
cavity, the lateral recesses of the epiccele are formed, and the
' ljateral masses of alba are considerable, while, except in the
medulla, little alba is seen on the meson. Within two days
after hatching the cranial flexure has nearly disappeared.

BRAIN OF OLDER LARVA AND OF RED FORMS.

Before the end of aquatic larval life the general longitudi-
nal proportions of the adult brain are attained, but the parts
are more depressed dorso-ventrally while the cavities are
large. ‘This appearance increases until the middle red stage
and corresponds with the general appearance of loose struc-

The Brain of Diemyctylus Viridescens 277

ture and growing spaces of this period. With continued
growth the structures become more compact.

The growth of the mesal walls of the cerebrum is slow,
the cells and alba forming the callosal eminence being gradu-
ally added until, before the adult stage is reached, it is fully
formed. The callosum and precommissure continue to be sep-
arated by cinerea up to adult life, and even in some small
adults the condition persists.

The compressed form of the ¢zfundibulum is lost by the
middle red stage. The saccus is sometimes quite convoluted
by the end of terrestrial life but this is apparently a variable
condition. "The hypophysis in the late red forms shows the
tubules widely open, but the large relative size of the organ
is not attained until adult life, though in the latter the tub-
ules again are more compressed. The original close approxi-
mation of the zofochord to the hypophysis (Fig. 67) is lost by
the middle red stage. The paraphysis is nearly as convo-
luted in the small red forms as in the adult owing to the ex-
tensive development of blood vessels in the supraplexus
which takes place at this stage.

By the end of aquatic larval life the roof of the mecencephal
has coalesced, the broad dorsal band of cinerea remains
through this stage, and fully grown red forms show a line of
cinerea on the dorsal side where the union took place. (See
p. 293). In the middle red stage the layers of cinerea are
forming while in late red forms the layers are more clearly
separated than in the adult—especially is the endyma separate
from the next cellular layer. ‘Traces of the caudal expansion
of the mesoccele remain until late red stages (Fig. 8).

The cerebellum is as large proportionally by the middle red
stage as in the adult, and at that time the extreme latero-
cephalic projection of the lateral recesses of the epiccele has
disappeared.

The metaplexus shows a median fold in a 16 mm. larva
while a mere trace of the metapore has appeared and consists
in the abrogation of a few cells of endyma (Fig. 57). In the
large aquatic larvee the metapore has not increased in size but
the metaplexus is as complex as in the adult. By the middle

278 Susanna Phelps Gage

red stage the metapore is larger and by the end of terrestrial
life the condition is practically the same as in the adult.

The pia and arachnoid are more clearly defined in the red
stages than in others, as owing to the more rapid growth of
the skull, the brain does not fill the cavity, and appears hung
in sheets of pia and supported by a spongework of arachnoid.

In early stages the dura has only a few pigment cells where
it is in contact with the epidermis on the dorsal side, these in-
crease gradually ventrad but even in the large red forms where
the pigment is scattered throughout the dura, it is small in
amount and of a browncolor. The great increase of pigment
in the dura seems to be associated with large size in the adult,
and in one very marked case, with a shrunken condition of the
brain.

The endolymphatic sacs in the larval forms are small, in
the red forms the relations of the parts are clearer than in the
adult (Fig. 8) because the sacs apparently are not so convo-
luted.

Between the brains of the adult male and female there ap-
pears to be no difference other than occurs between individuals
of the same sex.

SUMMARY.

From the above detailed description it isseen that the brain
of Diemyctylus resembles, in its embryonic, young larval and
adult stages, the brain in corresponding stages of other Uro-
deles ; and that there are no marked changes in the mor-
phology of the brain corresponding to the crises of develop-
ment and change in structure and function of the animal.
After the earliest stages of larval life, the parts of the brain
develop gradually, one after the other acquiring its mature
form, at periods which have no exact relation to those crises.
There is, however, a marked general growth at about the time
of final transformation so that the brain much more nearly fills
the skull than in the late red forms.

The grosser morphological plan was laid out before hatch-
ing, the details are added by gradual growth. It is possible
that in the finer structure of nerve cells, in the path of nerve

a

The Brain of Diemyctylus Viridescens 279

tracts, and their exact processes of growth, determined by
finer methods, a more complete correlation of brain structure
with these crises may be found.

PART II, PLATE VIE.
COMPARISONS WITH AMIA AND LAMPREY.

MATERIAL.

The brain in the skull of Ada calva was prepared, sectioned
and drawn by methods described for diemyctylus. Twelve
series of larval Petromyzon* were cut, some after hardening in
picric alcohol, but the more successful preparations were
hardened in mercuric chlorid.

The sections made agree in most particulars with the fig-
ures of Ahlborn (1) of lamprey and Goronowitsch (21) of the
amia. ‘The drawings presented add certain details, show
somewhat different structure or are necessary to illustrate the
comparisons here made. The reconstructed mesal views show
certain features not before noted.

A detailed account of the figures is given in the explanation
of Plate VIII, hence a consideration of special points will be
at once entered upon.

METAPORE.

Wilder (54) has demonstrated that in the adult man and
certain apes, in the caudal region of the metaplexus, there is
a lack of continuity in the endyma and pia, thus placing the
cavities of the brain in communication with subarachnoid
spaces. In lower forms such an opening has been considered,
from an embryological standpoint, as highly improbable, no
such break being found in early stages. In the amia (Fig.
93) a pocket of endyma extends caudad from the metaplexus

*It is impossible to state whether these were larvee of Petromyzon
marinus or of Ammocztes (Petromyzon) branchialis, since both lay
their eggs in the same streams and even the same nests, as shown in an
article by S. H. Gage in this volume.

280 Susanna Phelps Gage

over the cephalic end of the myel. In transection it hasa
considerable lateral extent. ‘The lamprey may be considered
to have a very small sac in a corresponding position (Fig. 111)
as, just cephalad of the closure of the myel, the walls ap-
proximate closely, the endyma being in contact except at the
dorsal limit where it swells out into a minute sac. In neither
lamprey nor amia was any lack of continuity in the endyma
seen. Rex (43) in this region of the elasmobranchs shows
that the vessels leave a little space at this point, though all
around they form a close meshwork, and Burckhardt (8) shows
a sac similar to amia in protopterus.

In diemyctylus such a pocket was not found nor, in the
earliest stages, any lack of continuity of the endyma. Ina
half grown aquatic larva the last section before the closure of
the myel shows that the endyma of the plexus is not complete
and the pia does not cross the meson, though in the section on
either side these conditions do not exist. This same condi-
tion was found in various series up to a full sized red form.
In a large red form and all the adults examined which were
perfect in this region the opening was inuch more pronounced,
and was observed in sections cut in different planes (Fig. 54-
56). Here the pia with its vessels extends toward the open-
ing but not across it, and the endymaisrecurved at the lateral
and caudal margins, but suddenly ceases, leaving a free com-
munication of the cavity with a subarachnoid space. It may
be objected that the cells lining the pigmented dura are en-
dymal cells, but they do not have the size nor appearance of
endymal cells and furthermore form a continuous layer lining
the dura in its whole circumference and are united by con-
nective-tissue like cells with the pia at frequent intervals as
in figure 55, av. ‘The recurved endyma may represent the
remnant of a stage like the amia.

After the most careful study of the sections, which show no
indication of tearing, delicate connective tissue cells and pro-
cesses retaining their position, the conclusion is unavoidable
that a true metapore exists in the adult diemyctylus, and that
its beginning or initial form arises in the larva.

The Brain of Diemyctylus Viridescens 281
INFUNDIBULUM.

Since the investigations of Miller in 1871, not much of fun-
damental importance has been added to the knowledge of this
region. It is thought desirable here to compare the extreme
variation in position of homolgous parts and to contrast the
simple and complex character of the region in different forms.
It seems that to give these parts collectively the name of a
lobe as has been done is misleading, but that the term, infun-
dibulum, long employed, may be used, apart from its strict
etymological significance, with reference to the whole region
and its appendages.

In the amia a cephalic projection of the cavity is associated
with the hypophysis (Fig. 93, 98) as is also the case with
lamprey (Fig. 103). In diemyctylus the whole infundibulum
extends caudad but the hypophysis is associated with the part
next the chiasma (Fig. 6).

In amia from the caudal part are four projections of the
cavity (Fig. 93, 100); the two dorsal are symmetrical, and
extend into the hypoaria; next a mesal cavity, short in ex-
tent; ventrad a longer extension, the saccus, with walls of
different structure, apparently non-nervous. In lamprey only
one caudal process exists (Fig. 103, 108), while in diemycty-
lus the relations are obscure. ‘There is a small lobular process
which in position corresponds with the saccus but the mem-
branous wall dorsad of it more nearly in structure resembles
the saccus (Fig. 6, 50).

CEREBRAI, COMMISSURES.

The variations in position of these commisures both with re-
lation to the brain masses and to each other seem to present one
of the most puzzling problems to be solved in comparative neu-
rology. The work of Reissner (42) and especially of Osborn
(38) in determining the existence and relations of the callosum
in im-mamuialia clearly showed these variations, the position
of the callosum and precommissure in urodeles being much
more like that in fishes than in anura. In the latter the con-
ditions are not dissimilar to those shown by Marchand (31) as

282 Susanna Phelps Gage

existing in the early human embryo, and also found in the
lower mammals. ‘Transitional forms must be looked for be-
tween the urodele and anurous conditions probably in em-
bryonic forms.

In the larval diemyctylus the position of these commissures
(Fig. 6, 91) even more than in the adult (Fig. 6) differs from
the frog in relation to the terma. In this and other urodeles
and in fishes (Fig. 93) the commissures are at the caudal
boundary of the large aula, the terma not rising directly from
them as in higher forms to the dorsal part of the porte, but
again dipping ventrad and curving around the large porte.
This is a modification of the embryonic condition in which
the aula extends, as the common cavity of the cerebrum, to
the cephalic extremity of the brain. It is as though the pro-
gress of the caudal development of the mesal walls of the cere-
brum, carrying the terma with them, were arrested in the
urodeles. Evidence of such a history is found in the larva
and the adult in the cinerea which reaches the mesal surface,
cephalad of the terma. In the young larva this consists
(Fig. 67, 76) of a single layer of endyma, which before the
end of larval life becomes several layered and in the adult
through a large part of its extent is a mass Of scattered cells
(Fig. 6, 15) reaching to the mesal surface.

In fishes the lateral and ventral curvature of the walls of
the cerebrum (p. 295) introduces another element of differ-
ence. In amia no commissure was found cephalad of the
compound one (cm. Fig. 93, 97) representing the callosum
and precommisure. Herrick (22, 24), however, in certain
teleosts and possibly in lepidosteus has found such a cephalic
commissure which he believes to be the callosum. Ahlborn
(1) shows a commissure which connects the olfactory lobes
directly, the precommissure (Fig. 103, 104). In the present
study of the lamprey brain, another band of alba in a position
easily overlooked, as it lies ventrad of a deep projection, was
found (Fig. 103, 105, cm.). This is more comparable in posi-
tion with the commissures of amia and diemyctylus than is
the precommissure, but it connects parts which seem homo-
logous with the striatums rather than with the callosal emi-

The Brain of Diemyctylus Viridescens 283

nence. With regard to the position of these commissures ;
the lamprey brain is in closer relationship with the anurous
than the urodele or fish type of brain, though, as was sug-
gested by Wilder (52) from other considerations, the brain of
lamprey is much like that of urodeles. It is hoped that the
facts now known with regard to these commissures may be
brought into harmony by further embryological study.

CRISTA.

In diemyctylus an object which, in comparison to the size
of the brain, is large, projects on the meson, freely into the
cavity of the aula, as shown both in transections and in
frontal sections. In the section cephalad of the porte (Fig.
16), it is seen that the endyma is reflected over a rounded
surface, the crista, to form the last remnant of the partition be-
tween the hemicerebrums. In frontal sections its base (Fig. 45)
joins the floor of the aula, but then projects into the aula and
toward the cerebral commissures. It contains white fibers,
apparently non-nervous, with a herring-bone arrangement on
either side of a loop of pia which extends far into it (Fig. 46).
Its dorsal side (Fig. 47) showing endymal cells in face view,
retreats to the general level of the terma, except that a slight
ridge extends dorsad from it (Fig. 37), and this ridge (Fig.
36) is the point from which the endyma is reflected to form
the auliplexus and (Fig. 35) the mesal walls of the cerebrum.

In the larva (Fig. 71, 72) a trace of this structure is visi-
ble. Here, owing to the large aula, it is relatively farther
cephalad. In the twelve-day embryos it is far cephalad, be-
ing the first indication of the restriction of the aula. In later
embryos it still is far cephalad (Fig. 73, 74). In all these
cases this projection bears the same relation to the rudi-
mentary mesal walls of the cerebrum as in the adult, though,
in the embryos, the auliplexus is not yet developed. Hence,
morphologically it is the dorsal limit of the terma, a kind of
fixed point beyond which the olfactory lobes and the cere-
brum project in their growth and from which the auliplexus
is reflected.

In the amia a structure which agrees in position with the

284 Susanna Phelps Gage

above is seen to rise between the hemicerebrums (Fig. 95,
96), and is the ridge over which the endyma is reflected to
form the partition between the hemicerebrums, this partition
being in reality a plexus in the aula—auliplexus. Caudad of
the reflection of the auliplexus it projects as a ridge into the
aula, gradually becoming lower, and contains fibers probably
of connective tissue, which are directed toward a mesal blood
vessel (Fig 96), extending into it as in diemyctylus. Rabl-
Rtickhard shows a ridge in this situation in a bony fish (40).
No such structure was detected in the lamprey.

The discussion of this apparently insignificant part of the
brain has been introduced under the name crista, since that
term has been used by Wilder (53) to designate a small,
rounded body, seen from the aula resting upon the fornix and
dorsad of the precommissure, in the adult cat and sheep and
human embryos. At his suggestion, sections of this region
in the cat have been made. Figures 48, 49, are through
the columns of the fornix. The only noticeable fea-
ture in the structure is the fact that it contains rows
of cells which are arranged at right angles to those of the
fornix and that pia is found between the columns of the
fornix extending almost to the crista. If, as in the fornix
and other situations, these rows of cells indicate arrangement
of fibers, it is not improbable that fibers may be present here
which represent those seen in diemyctylus. The pia is cut
off from actual entrance into the crista by the close union of
the fornicolumns, but the appearance is very suggestive of
that in diemyctylus, though there is no complete likeness of
‘structure. In position it seems comparable to that body in
diemyctylus, as it lies in the primitive terma which is dis-
guised by the growth of the callosum and fornix, between the
porte, near the point where the auliplexus is reflected, and
in the same morphological relation to the precommissure ;
hence the term crista is used to designate the part in diemyc-
tylus and amia, and if found in other forms will be a valuable
landmark in determining the relations of aula and commissures.

The Brain of Diemyctylus Viridescens 285
EPIPHYSIS AND PARAPHYSIS.

In the roof of the brain two outgrowths from the cavities
have been found in embryos of all groups, the epiphysis
arising from the diencephal between the supra- and postcom-
missures, the paraphysis farther cephalad and variously said
to belong to the prosen- and diencephal. From a morpholog-
ical standpoint the importance of these organs has been con-
sidered great, hence many special articles have been devoted
tothem. ‘The history and present state of knowledge con-
cerning them has recently been discussed by Béraneck (5) and
His (27). In brief, the epiphysis is said to develop variously
in different groups, becoming the pineal or parietal eye of
lizards and lamprey, the conarium of mammals, while in am-
phibia it is very degenerate and was first discovered by Gotte
(20). The fate of the paraphysis in the adult has been very
uncertain. Observations of Hoffmann (28) are very suggestive
with reference to the possible relation of the neuropore with
the paraphysis.

Epiphysis.—As seen in the figures the epiphysis of diemyc-
tylus like that of other urodeles is insignificant. In embryos
it is prominent, in the early larval stages a remnant of its
connection with the brain remains (Fig. 68) occuring as usual
between the supra- and postcommissures. In the adult this
connection has disappeared and its cavity is nearly obliterated.
Figure 58 shows a few lacunz in it and the fact that it is in a
region of numerous blood vessels. From its caudal enda few
fibers pass toward the roof of the mesencephal forming a pic-
ture (Fig. 52) which resembles the condition in the frog as
shown by Osborn (37). From the degenerate condition it
would probably be impossible to determine whether these are
nervous or connective tissue elements.

In the amia as in other ganoids, the epiphysis lies to the
left of the meson, owing to the greater development of the
right habena (Fig. 97-99). In this specimen figured, which
is nearly adult, the stalk can be traced to its union with the
brain. This union is by a tortuous path owing to the crowd-
ing of the habene.

286 Susanna Phelps Gage

Since the researches of Ahlborn (1) showed the nature
of the pineal eye or epiphysis in lamprey, it has been settled
that its stalk retains its connection with the brain at least
through larval life. This connection is very clear in the spec-
imens studied (Fig. 103), but the nerve which Béraneck (5)
claims to have found connecting the epiphysis to the mesen-
encephal, was not seen. The pigment of the organ agrees
with the condition said to belong to this stage of develop-
ment by Beard (4), that is, it is white by reflected light. He
says that in both earlier and later stages black pigment is
found. The white pigment extends from the floor of the
epiphysis into the hollow stalk for some little distance (Fig.
104, 105) then the stalk becomes inconspicuous and passes be-
tween the two habene, to its union with the brain at the left
of the middle, but on a morphological meson (Fig. 103, 109).

Paraphysis.—In diemyctylus before hatching, a cross parti-
tion divides the prosen- from the diencephal and from this ‘is
another dividing the prosencephal into right and left hemicere-
brums. ‘This TI’ shaped partition so formed is permanent.
Into the space where the two bars join is developed from the
brain cavity the first trace of the paraphysis (Fig. 73). This,
from the curvature of the brain, is a cephalic structure.
When the flexure is lost the paraphysis retains its relative po-
sition but becomes a dorsal structure (Fig. 67), the stem of the
T is represented by the mesal walls of the hemicerebrums with
intervening pia, the cross bar is the fold cephalad of the di-
encephal in which the supraplexus and paraphysis occur. In
the larva the tube has an enlarged bulbous end (Fig. 66) and
is composed of a single layer of cubical epithelium. Around
this tube are a few small vessels and scattered cells, the begin-
nings of the supraplexus. Eycleshymer (12) identified and
has given an excellent account of the paraphysis in amblys-
toma up to this point of development, but in 14 mm. larvee
he says its proximal cavity is obliterated. This is not the
case in diemyctylus, for in the adult the connection with the
brain cavity still exists though it is constricted. The cavity
continues to increase in size but by the beginning red stage
it is convoluted by the growth of blood vessels which press

Se

The Brain of Diemyctylus Viridescens 287

upon it, and in the adult it is a very irregular sac lying in
the midst of the supraplexus (Fig. 51, 53, 59,60). The open-
ing is upon the meson at a point between the blood vessels
supplying the dia- and auliplexuses. (See p. 265). This
opening cannot be said to be into either diaccele or aula but
rather, anomolous as it may seem, to mark the boundary be-
tween the two, for the cells next it on the caudal side belong
to the diencephal, on the cephalic side, tothe aula. As Eycles-
hymer noted, the paraphysis is separated from the epiphysis for
some distance, the precommissure, habenz and a stretch of
endyma and a plexus intervening between their openings
(Fig. 6, 52).

The dorsal sac of fishes is a well known structure, it is large
and conspicuous, and the pallium, the membranous roof of the
prosencephal, is beneath, and united with it.

In the amia the pallium (Fig. 93) is a membrane overlying
which are great numbers of blood vessels, with branches into
the intercerebral plexus (auliplexus) and the intercerebral pia
in a way perfectly comparable to the arrangement of vessels
from the supraplexus of diemyctylus (p. 265). Partly thrust
into this mass of blood vessles and convoluted by them—partly
overlying them, is the dorsal sac, which as seen from the meson
has a narrow connection with the cavity (Fig. 93, par.), but in
transection has a wide orifice (Fig. 98). It is a pocket or sac
of endyma reflected from the supracommissure with a diver-
ticulum extending caudad over the supracommissure and
habenz (Fig. 99). The stalk of the epiphysis arising as it
does caudad of the supracommissure is thus brought into con-
tact with the dorsal sac and continues cephalad upon it or
partly enclosed in it (Fig. 98) and from this arrangement the
term second vesicle of the Epiphysis has been applied (Zzrébel-
polster of German writers).

As in amia and lamprey there is no partition dipping ven-
trad, between the prosen- and diencephal in which the para-
physis may be sought, the essential relations of the above parts
must be considered. The pallium with regard to its vessels is
comparable to the supraplexus, and its endyma to the mem-
brane from which the paraphysis rises in the diemyctylus, (see

288 Susanna Phelps Gage

p. 293 and compare Fig. 93, 6). The caudal diverticulum
of the sac many be compared to the thin layer in diemyctylus
forming the cephalic boundary of the diencephal (Fig. 6, 68,
52) then the remainder of the sac meets the requirements
of homology with the paraphysis of amphibia,—a thin
walled diverticulum from the caudal part of the pallium,
partly surrounded by bloodvessels and having the same rela-
tion to supracommissure and habenee.

Balfour and Parker (3, p. 377) described in lepidosteus a
large sac which they say is homologous with Stannius’ sac in
the sturgeon ; a similar one was described by Wiedersheim
in protopterus. Goronowitsch (21) has made the relations of
this sac very clear in the ganoid, and Burckhardt (8) in the
dipnoan brain. ‘The conclusion with regard to the homology
of this sac, above deduced in the amia, is confirmed by the
figures and description of the former, while from Burckhardt’s
results it may be concluded that the dipnoan brain agrees
even more closely in this respect with the amphibian.
He shows a dorsal sac divided into a part which is
cephalad of the supracommissure, and may be compared with
the caudal diverticulum in amia (Fig. 99), and the layer of
epithelium cephalad of the diencephal in diemyctylus (Fig.
68); and a so-called conarium separated from the above by a
velum. His conarium, the Adergeflectknoten of other Ger-
man authors—the supraplexus—is a-large sac with blood ves-
sels aroundit. The velum, though small, exactly corresponds
in position with the diaplexus of diemyctylus, while from its
cephalic border are given off the paraplexuses. Whether a
true auliplexus exists cannot be determined from his figures,
but in its essential relations his conarium seems to be the
paraphysis of amphibia.

This second vesicle of the epiphysis as it is some-
times called, is a marked feature of the lamprey’s brain,
as of the reptile’s. Ahlborn (1) shows it in lamprey lying
ventrad of the epiphysis or pineal eye. He considers that the
cavity of the epiphysis opens into the cavity of the second
vesicle ; that the left habena which extends as a white band
far beyond the right to the second vesicle, forms the nervous

The Brain of Diemyctylus Viridescens 289

connection of the pineal eye with the brain. He says (p. 282)
that some of his sections seem to indicate that an opening
exists between the second vesicle and the brain cavity. Gas-
kell (19, p. 433) considers that the left habena serves as the
nerve for this sac and the right as a nerve for the epiphysis.

From the present investigation no indication of the opening
of the cavity of the epiphysis into the sac lying ventrad of it
is found, in fact the two are separated by a connective tissue
cushion and a blood vessel (Fig. 104, 105). Nor is there in-
dication that the habenz serve as nerves for either the epi-
physis or this sac, though there may be a correlation of their
unequal size with the comparatively developed condition of
the epiphysis. The left habena (Fig. 105) extends under the
epiphysis. At the right is seen a small cavity opening into
the general cavity. This is the second vesicle and probably
the opening which Alhborn considered as possible. Figure
104 shows a more cephalic section in which the tip of the left
habena, covered by endyma, extends into the same cavity
but maintains its lateral position with regard toit. The re-
construction of the cavity is shown in figure 103, where it is
represented upon the meson though its opening is not
exactly at the middle of the section. This is because an
organ, the left habena, which is admitted to be morphologi-
cally a lateral organ, has, from unequal growth, assumed a
mesal position and pushed aside a small mesal structure.

From the relation of this second vesicle to the habena, and the
supracommissure, from its morphologically mesal position, and
its relation to a blood vessel dorsad of it, I conclude that it is
the paraphysis, even though no plexuses in the brain serve
further to determine itsidentity. This is in consonance with
the statement of Scott (46) that in the earlier stages of petro-
myzon, the two dorsal vesicles are soon pushed to the left of
the meson ; and of Goronowitsch (21) that in Acipenser ruth-
enus the habenz and dorsal sac are asymmetrical.

In the adult of mammals the remains of the second and
more cephalic of the two mesal outgrowths observed in the
embryo has not been identified. The caudal is the cona-
rium. In man and very markedly in the sheep, as shown by

290 Susanna Phelps Gage

Wilder (55, Fig. 4711, 57, Fig. 25) there is a mesal pocket
of endyma which is reflected from the supracommissure over
the cephalic aspect of the conarium. Cephalad it is contin-
uous with the endyma covering the plexuses which lie in the
elongated interval between this point and the porta. Whether
this sac with its cephalic extension to the porta, and its
intimate relation to the large vessels and plexuses which lie
dorsad of it can be identified with the paraphysis of amphibia
is not known but certainly a strong resemblance to the facts in
diemyctylus can be seen. As the roof of the cavities in this
region is a mere membrane it does not seem improbable that a
structure, in lower forms closer to the porte, might be drawn,
with the great vessels with which it is associated, to a distant
point by the growth of the callosum, around the caudal end of
which those great vessels effect their entrance to the brain
plexuses.

Burckhardt (7, p. 398) suggests that the caudal border of the
supraplexus rather than the supracommissure be considered
as the boundary between the prosen-and diencephal. From
the preceding studies it would appear that the opening of the
paraphysis would be a more exact demarcation in the groups
in which it has been identified especially if the form found in
amphibia be considered from its exact definiteness, the typical
condition. The embryonic form (Fig. 73) with the open-
ing of the paraphysis in a partition between the two segments
would be the point of departure, on the one hand, toward
those forms in which the segments are not divided by a parti-
tion and which have no plexuses, on the other toward those
in which the plexuses are well developed and the segments
distinct.

In fishes this. would be a convenient landmark, as in am-
phibia. In lamprey the part in which the left habena lies
must be conceded to belong to the diencephal hence the ex-
treme cephalic position of the part here called paraphysis need
not be a bar to considering its opening as the dorsal limit be-
tween the prosen-and diencephal. Among the mammals,
should the inference made above as to the paraphysis be cor-
rect, the case is more difficult because much, or perhaps all of

The Brain of Diemyctylus Viridescens 291

the long plexus between the portee and conarium would be-
long to the prosencephal. The relations of the plexuses in
man as shown by Wilder (55, Figs. 4743, 4711) are very dif-
ferent from those found in amphibia, unless some new light
shall be thrown upon them by the study of sections by the
microscope. Upon such a study must depend the determina-
tion of the homologies of the plexuses and consequently
the dorsal limit between the segments.

The cells of the paraphysis of diemyctylus are cubical and
not flattened as over the plexuses. Jeffries Wyman (59) ac-
curately described and figured cells in the frog, which were
taken from the midst of the vascular mass (supraplexus) and
surmised that they were part of the brain wall proper. This
is the earliest reference which I have found to this structure
(the paraphysis) but it has been overlooked in the extensive
bibliographies upon the epiphysis and paraphysis in which the
discovery has been assigned to much later investigators.

The original use of this organ has been by some considered
as an eye (19) by others (45) as an auditory organ. Another
surmise may be ventured. From its origin in the embryo be-
fore the plexuses are formed, in a region, which by later
growth as shown by its extensive vascular supply, has need of
a means of repairing waste; from the character of the one
layered endyma in the amphibia, it is suggested that it is con-
nected, at least in early stages, with the nourishment of the

brain.
SULCI.

In the mentencephal of human embryos, His (26) has very
carefully worked out the relation of the origin of nerve roots to
certain folds in the brain wall which become the center of cell
proliferation. ‘These arise at a margin between the solid and
membranous portion of the wall (see Fig. 86, 92, which show
such folds at the origin of the 9th and 7th nerves), and may be
gradually overgrown by a new fold; thus pushed together,
they may coalesce and apparently disappear as true folds. (See
wing of cinerea with which the roth is connected in Fig. 86).
These folds he calls Rautenlippen. ‘The relation of such folds
with nerve roots is clearly shown by Goronowitsch (21) in

292 Susanna Phelps Gage

acipenser and amia. In figure 93 is a representation of the
position and length of these folds as seen from the meson.
It is proposed to call these depressions, sz/cz, in analogy with
the term sulcus of Monro which is considered as a feature
of great morphological significance, and to differentiate these
endymal depressions from the fissures of the ectal surface.
To a ridge between two sulci the term Jophius, Gr. Aodos,
ridge, is proposed. ‘‘ Rautenlippe’’ is ill adapted to English
and French, while furrow and ridge are not capable of univer-
sal application.

In man, His has recognized that one sulcus, the sulcus of
Monro, has a morphological significance, indicating the bound-
ary in the cephalic region between the dorsal and ventral
zones (34). Inthe present investigation it has become evi-
dent that not only this and those of the metencephal but also
other sulci in the cephalic parts of the brain may be looked
upon as occurring at definite places with definite relations in
the three forms studied. In the region of the metencephal the
sulci are most clearly defined. In the larval diemyctylus the
mesen-and diencephal show sulci clearly. Inthe adult some of
these have become nearly obliterated on the endymal surface
but can be clearly seen in section by the bulging of the cine-
rea (p. 275). In lamprey the endymal surface is not much
thrown into folds and the cinerea is not clearly defined as in
the diemyctylus, but from definite points the cinerea is seen
to be continuous with the endyma, the cells, so to speak,
streaming off in definite channels. In the amia the sulci ap-
pear, but the indefinite arrangement of the cells does not as
yet help in the solution of the question.

It is hoped soon to make a comparative study of these sulci '
in different forms and to bring them into correlation, but cer-
tain of them are now definite enough to be used in the follow-
ing discussion. ;

MESENCEPHAL,.

The lobes of the mesencephal in the urodeles unite by a
broad band and form a slight depression, at least in diemycty-
lus, upon the dorsimeson (Fig. 24). In fishes, reptiles, etc.,

The Brain of Diemyctylus Viridescens 293

the parts unite and a distinct commissural band is present
while there is a great depression on the dorsimeson separat-
ing the parts into two lateral lobes (geminums Fig. 100). In
larval diemyctylus, though the walls approximate each other,
they unite across the meson merely by a layer of endymal
cells (Fig. 81). In the lamprey the solid parietes show a
bend, or sulcus, similar to that of the amia but the flexure is
not as great, nor do the parts unite across the meson except by
a wide membrane (Fig. 108). The membrane is plexiform
with a mesal fold, while at the union of the membrane with
the solid wall the endyma is reflected over a ridge or lophius
comparable to those of the metencephal. ‘These different
forms arise from a common embryonic one where the walls are
thin and uniform.

This recapitulation and comparison of figures is introduced
to recall the fact, that in parts which are homologized without
hesitation, the mere condition of a more or less upright posi-
tion and the closer or more remote union by a well organized
commissural band or a mere membrane are not considered
bars to such homologizing.

PALLIUM.

Since Rabl-Rtickhard’s (40) memorable work on the brain
of fishes, the pallium has been known as a membrane which
represents and takes the place morphologically of the dorsal
and mesal walls of the cerebrum of other groups. A recent
work of Herrick upon the ganoids (24, p. 153), shows that he
considers the portee of other forms to be represented by the space
between the proplexus [auliplexus] dividing the hemicere-
brums and the floor of the prosencephal. They are elongated
siitss)) | Phese changes.) ). 1. and the backward revolu-
tion of the mantle portion of the cerebrums make all the diffi-
culties disappear, and we seek the commissures of the mantle
far cephalad in front of the thin membranous portion, which
seems to be homologous, in part at least, with the velum cere-
bri supporting the proplexus.’’ Here isa hint that he has
seen a new interpretation of the pallium though in other parts
of the article he seems to accept in full the idea of Rabl-
Rtickhard.

294 Susanna Phelps Gage

A reconsideration of the exact relation of parts seems de-
sirable. At its middle, the pallium extends over the cere-
brum (Fig. 97) and far around to the lateral aspect. Farther
cephalad it is divided by a mesal partition into two parts.
The cavities so enclosed are sometimes called lateral ventri-
cles. ‘The partition extends caudad soon, however, ceasing
to form a complete separation but hanging as a plexus into
the common cavity of the prosencephal, the auliplexus. Cau-
dad the pallium opens into the dorsal sac, paraphysis (Fig.
98). At the level of this figure it is seen to be reflected
laterad over a rounded ridge which, in tracing caudad, is seen
to be directly ventrad of the knob known as the habena (Fig.
99). The little sulcus s/ is the caudal extension of the lateral
pocket formed by the pallium (Fig. 98 s/7), and the outer border
of this pocket z, corresponds to the union of pallium and cere-
brum (Fig. 97 2).

In the lamprey a section (Fig. 106) which cuts the habenze
as does figure 99 in amia, shows that ventrad of the habena
on the left is a sulcus, on the right a membranous exten-
sion of endyma. Following these cephalad (Fig. 105) the
supporting columns of the habenze disappear and the lateral
pockets of endyma extend beyond the cerebrum, while be-
tween them arises the small sac here called the paraphysis.
At the side these sacs are reflected over the lip of the cere-
brum. Imagine the dorsal limb of the cerebrum (Fig. 105)
revolved laterad and then in their essential relations these
sacs are an exact counterpart of the pallium of fishes, though
the great ceplialic extension of the left habena disguises the
fact somewhat.

In amphibia and higher forms is it possible to recognize
such a membrane? In figure 22 are seen sulci ventrad of the
habenze. These traced cephalad become the slight lateral
recesses seen at each side of the opening into the paraphysis
(Fig. 21, 53, 20, p/.). In figure 19 the membrane is divided by
the intrusion of the auliplexus. Cephalad of the opening of
the porte the union of the membrane with the cerebrum is
characterized by a reflection of endyma over a rounded ridge
(Fig. 18, 101 2), at the ventral end of the mesal wall of the

The Brain of Diemyctylus Viridescens 295

cerebrum. Small as these parts are, from the exact coinci-
dence with the essential points in the topography of the pal-
lium of amia, I think they can be safely homologized there-
‘with, provided that it is admitted that the mesal wall of the
cerebrum in amphibia corresponds with an extreme lateral
point in fishes, that is, if the points at which the membrane
attaches to the cerebrum are homologous.

The figures by Mihalkovics (33) of the brain of an embryo
rabbit show relations of the membranes much like those of
diemyctylus.

CEREBRUM.

In figures 97, Io1, 105 are shown sections through the
brain of amia, diemyctylus and lamprey respectively in
regions as accurately corresponding as possible,—through the
cerebral commissures. In the lamprey the cavity of the pros-
encephal extends at right angles from the meson and the dor-
sal walls may easily be imagined as bent downward so that
the actual condition should be as in diemyctylus, or away
from the meson when the position would correspond with the
interrupted lines of figure rot.

In the amia suppose that the recurved cerebrum be raised
to a nearly vertical position as shown by the interrupted lines
of figure 97. A strict comparison could be instituted be-
tween the forms, which would produce no more change than
occurs in nature in the position of the walls of the mesencephal
of different groups (p. 292). In figure 97 with the exception
of stretching the line between y and y’ and folding the pal-
lium to form a paraplexus no change except raising the parts
is necessary. In the young amia (Fig. 102) as shown by
Wilder (50), young gar, shown by Wright (58), lepidosteus
shown by Balfour and Parker (3, Pl. 24), the walls actually
have the position here imagined in the adult.

In figure 97 it is noticeable that a band of alba can be seen
continuous with the commissure, passing ectally around the
sharp angle at y to the point z, where the pallium unites with
the solid wall. To prove that the part between x and z in this
figure is identical morphologically with the corresponding

2096 Susanna Phelps Gage

part of figure ror, that is with the callosal eminence, it is
necessary to prove that fibers representing a true callosum
enter this part. The researches of Herrick upon the bony
fishes (25) show that callosal fibers do reach an extremely
lateral position, the hippocampal lobe as he calls it, but more
extended studies are necessary.

In figures 95 and 97 are seen slight undulations in the en-
dymal surface of the cerebrum. These are continuous for
some distance cephalo-caudad. In bony fishes similar undula-
tions have been noted by Herrick (25) and given the name of
fissures found in mammals upon the ectal surface of the
brain and by means of them he has divided the cerebrum into
lobes, despite the fact that they are upon endymal surfaces.
A better explanation seems to me involved in the term sulci,
to designate them ; that is, definite folds in the endymal sur-
face which have a morphological significance. Here they
would indicate and correspond to the sulci so marked in
the paracceles of diemyctylus at which the mesal walls bend over
from the lateral wall. An illustration of the facts which seem
to exist, is afforded by placing the ball of the thumbs toward
each other, as much recurved as possible. This represents
the amia brain, the edge of the nail the point of reflexion of
the pallium, the creases at the joints the almost obliterated
sulci of the cerebrum. Flexing the thumbs and placing the
nails toward each other, the form of the diemyctylus brain is
represented, the edge of the nail is the point at which the
endyma is reflected to form the pallium and plexuses, while
the sharp angles at the joints are the deep sulci occurring at
the points where the brain wall changes its direction.

How exactly homologies can be established between the
sulci in different groups in unknown but from the present
study it is believed that the more important of these will be
found to occur in similar regions of the cerebrum.

If the above interpretation of pallium, auliplexus and cere-
brum receives confirmation from more extended observations,
brains with recurved cerebrums cannot be said to have true
portee, the opening into the olfactory lobes representing a part
only of the portee of amphibia. The opening from the aula is

The Brain of Diemyctylus Viridescens 297

not circumscribed by homologous parts in the two types. The
term paraccele however, applying to the space between the
cerebrum and pallium in fishes is perfectly comparable to the
paraccele of other forms.

RHINENCEPHAL,

In this article the term rhinencephal has been used as
though the olfactory region might be considered a segment as
independent as the prosencephal. The lack of a distinct
mesal portion in higher forms has led Wilder (56 p. 114) to
reject such independence.

Upon embryological grounds it seems as though the rhinen-
cephal were equally entitled with the prosencephal to a share
of the aula as a mesal cavity. In the embryo there are two
portions of the forebrain—one associated with the developing
olfactory nerves, the other lying next the diencephal—with a
large common cavity. In the larval diemyctylus (Fig. 71),
a cephalic part of the cavity belongs to the olfactory region, a
caudal to the cerebrum ; the porta gives free opening of both
into the aula. With the growth of the callosum and callosal
eminence, the olfactory lobes are pushed away from their evi-
dent connection with the aula by that which may be called an
intercalated portion of the cerebrum ; the caudal part of the
cerebrum retains its original relations (Fig. 36).

The brain of the lamprey (Fig. 103), does not progress be-
yond the condition of the larval diemyctylus. From the
porta the cavity forks, the cephalic part extending into the
olfactory lobe (Fig. 104), the caudal, a short distance into the
cerebrum proper (Fig. 106).

From sections of amia (Fig. 93-95) it is seen that on the
ventral side it is difficult to set a caudal limit to the olfactory
lobe which may extend quite to the precommissure. The pros-
encephal would then be represented by a wedge with a nar-
row base, both segments having equal share in the large aula.

In adult mammals the original conditions are masked by
the great growth of the callosum and fornix but in early
embryos the relations are simple and not unlike that of the

298 Susanna Phelps Gage

larval diemyctylus. The development of the cerebral com-
missures (p. 281) will undoubtedly throw further light on the
question of the rhinencephal as a separate segment.

SUMMARY.

1. A true metapore exists in adult diemyctylus and indi-
cations of it appear in larvee. In lamprey and amia at a cor-
responding part of the metaplexus a sac communicating with
the metaccele protrudes over the myel.

2. The callosum and the callosal eminence are only begin-
ning to develop in early larvze of diemyctylus, and the posi-
tion of the cerebral commissures differs, in early stages, more
from the anurous type than does the adult, the aula being
much larger proportionately. The type in urodeles and fishes
may be one of an arrested embryonic development. In the
diemyctylus there is evidence, in the adult, of a caudal growth
of the terma which if continued would bring the commissures
in the same relation to the terma as in the frog and higher
forms.

3. The crista in diemyctylus and amia is shown to be a defi-
nite structure beyond which the cerebrum develops cephalad
and from over which the auliplexus is reflected, and thus is a
landmark in discussing the relations of the aula and cerebral
commiissures.

4. The paraphysis of diemyctylus is traced through differ-
ent stages of development and homologies discussed in amia
and lamprey, and a possible use in the nourishment of the
brain is suggested.

5. Sulcus is proposed as a general term for the furrows on
the endymal surface, which have a morphological significance,
and lophius for the ridges between sulci.

6. In the discussion of the geminums it is shown that
homologies are not dependent upon the membranous or solid
condition of the roof nor the angie at which the parts unite.

7. The morphological relations of the pallium are considered
in amia and its homolog in amphibia and lamprey suggested.

8. The cerebrum of amia and other fishes is not to be
considered from its recurved position as different from other

The Brain of Diemyctylus Viridescens 299

types. The sulci upon its endymal surface are compared
with those of diemyctylus. The pallium is considered as a
plexus much stretched, not an undeveloped part representing
the dorsal and mesal walls of other brains.

9. Arguments and facts are given for considering the rhin-
encephal as equal to other segments having a tripartite
arrangement.

This investigation has been carried on in the Anatomical
Laboratory of Cornell University where material and appli-
ances were most generously placed at my disposal. To the
writings of Dr. Wilder many references have been made but
to his lectures especially am I indebted for the full discussion
of morphological problems and especially of the difficulties
involved.

RETACA, SNe Y's;
Aung. 19, 1893.

BIBLIOGRAPHY.

A complete historical bibliography upon all parts of the
brain discussed in this article would be too voluminous, hence
in some cases a recent article containing a historical summary
and bibliography is referred to in preference to older work.

x. AHLBORN, F.—Untersuchungen uber das Gehirn der Petromyzonten.
Zeit. wiss. Zool. XX XIX, 1883, pp. 191-294; 5 pl. In the pineal
eye is a white pigment which is not transparent. p. 230.

2. AYERS, H.—Vertebrate cephalogenesis. II. A contribution to the
morphology of the vertebrate ear. Jour. Morph. VI, 1892, pp.
I-360; 26 figs. 12 pl. p. 129 shows close relation of 7th and 8th
nerves, p. 20, 50 discusses relations of endolymphatic sac.

3. BALFour, F. M. and W. N. PARKER.— On the structure and devel-
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4. BEARD, J.—The parietal eye in fishes, a note. Nature, XXXVI,
1887, p. 340. In the young larve of petromyzon the pigment is
black, in older larvae, white, and in the adult, black. The relation-
ship of these pigments in the parietal eye is unknown.

5. BERANECK, Ep.—Sur le nerf pariétal et la morphologie du troisiéme
ceil des vertébrés. Anat. Anz. VII, 1892, pp. 674-689. Thinks that
there are three unpaired dorsal structures—paraphysis, parietal eye,
and epiphysis—the parietal having a distinct nerve; the paraphysis
appearing later than the other two, arose from the prosencephal. A
good historical review.

©. BURCKHARDT, R.—Untersuchungen am Hirn und Geruchsorgan von
Triton und Ichthyophis. Zeit. f. wiss. Zool. LII, 1891, pp. 369-403;

2 pl.

97. —— Die Zirbel von Jchthyophis glutinosus und Protopterus an-
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8. —— Das Central-nerven-system von Protopterus annectens. 8°,

pp. 64;.5 pl. Berlin, 1892. A preliminary paper in Jour. Comp.
Neur. II, 1892, pp. 89-91; 1 pl.

g. EcKER, A.—The anatomy of the frog. Trans. by G. Haslam. 8°,
PP. 449; 261 figs. Oxford, 1889.

1O. EDINGER, L,.—Das Zwischenhirn der Selachier und der Amphi-
bien. 4°, pp. 84; 5 pl. Frankfurt, a. M., 1892. Abstr. in Anat.
Anz. VII, 1892, pp. 472-476. Especially shows fiber tracts which
have not been discussed in this paper.

Ir. — Vergleichend-entwickelungsgeschichte und anatomische Stu-
dien im Bereiche der Hirnanatomie. 3. Riechapparat und Ammons-
horn. Anat. Anz VIII, 1893, pp. 305-321; 6 figs.

12. EYCLESHYMER, A. C.—Paraphysis and epiphysis in Amblystoma.
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The Brain of Dienyctylus Viridescens 301

13. FISHER, J. G.—Anatomische Abhandlungen uber die Perenni-
branchiaten und Derotremen. pp. 170,6 pl. Hamburg, 1864.

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lagen in der Occipitalregion. Arch. f. Anat. u. Phys., Anat.
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16. GAGE, SIMON H.—Life-history of the vermilion-spotted newt.
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1084-1110, 1 pl. A nearly complete history of the transformations
from a larval, aquatic, gilled, viridescent form, to a terrestrial,
gill-less, red form, and again to an aquatic, partially water breathing,
viridescent form.

17. —— Methods of decalcification in which the structural elements
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18. GAGE, SUSANNA PHELPS.—A preliminary account of the brain of
Diemyctylus viridescens, based upon sections made through the
entire head. Amer. Assoc. Adv. Sci. Proc., XLI, 1892, p. 197.

Ig. GASKELL, W. H.—On the origin of vertebrates from a crustacean-
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20. GOTTE, A.—Die Entwickelungsgeschichte der Unke. pp. 964,
Atlas 22 pl. Leipzig, 1875.

2x. GoronowitscH, N.—Das Gehirn und die Cranial-nerven von Acz-
penser ruthenus. Morph. Jahr., XIII, 1888, pp. 427-574, 7 pl.
The most complete account of the ganoid brain since the introduc-
tion of the modern methods of hardening and sectioning.

22. HERRICK, C. L.—The commissures and histology of the teleost
brain. Anat. Anz., VI, 1891, pp. 676-681, 3 figs.

Contributions to the comparative morphology of the central

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23.

24. —— Topography and histology of the brain of certain ganoid
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Jour. Comp. Neur., I, 1891, pp. 228-245, 4 pl.

26. His, WM.—Die Entwickelung des menschlichen Rautenhirns vom
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28. Horrmann, C. K.—Weitere Untersuchungen zur Entwickelungs-
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2Q9. JOHNSON, ALICE, and LILIAN SHELDON.—Notes on the develop-
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30. KINGSLEY, J. S.—The head of an embryo Amphiuma. Amer.
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3X. MarcHAND, F.—Ueber die Entwickelung des Balkens im men-
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302 Susanna Phelps Gage

32. Mason, J. D.—Minute structure of the nervous system of certain
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34. Mrnor, C. S.—Human embryology. 8°, pp. 815, 463 figs. Ex-
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nerves.

35. Naxacawa, I.—The origin of the cerebral cortex and the homolo-
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36. Norris, H. W.—Studies on the development of the ear of Am-
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37. OsBorN, H. F.—Preliminary observations upon the brain of Meno-
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38. —— The origin of the corpus callosum ; a contribution upon the
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223-251, 530-543, 3 pl., 7 figs.

. — A contribution to the internal structure of the amphibian
brain. Jour. Morph., II, 1888, pp. 51-96, 3 pl.

40. RABL-RUCKHARD.—Das Grosshirn der Knochenfische und seine
Anhangsgebilde. Arch. f. Anat. u. Phys., Anat. Abth., 1883, pp.
279-322, 2 pl.

41. — Zur onto- und phylogenetischen Entwicklung des Torus long-
itudinalis im Mittelhirn der Knochenfische. Anat. Anz., II, 1887,
PP- 549-S5!-

42. REISSNER, E.—Der Bau des Centralnervensystems der ungesch-
wauzten Batrachier. Text und atlas. pp. 98,12 pl. Dorpat, 1864.

43. REx, H.—Beitrage zur Morphologie der Hirnvenen der Elasmo-
branchier. Morph. Jahr., XVII, 1891, pp. 417-467, 3 pl.

. — Beitrage zur Morphologie der Hirnvenen der Amphibien.
Morph. Jahr., XIX, 1892-3, pp. 295-311, I pl.

45. SELENKA, E.—Das Stirnorgan der Wirbeltiere. Biol. Centralb.,
X, 1890, pp. 323-326.

46. Scorr, W.—Notes on the embryology of Petromyzon. Jour.
Morph., I, 1887, pp. 253-302, 3 pl.

47. STIEDA, L.—Studien iiber das centrale Nervensystem der Wirbel-
thiere. 8°, pp. 184, 4 pl. Leipzig, 1870.

48. STRONG, O. S.—The structure and homologies of the cranial
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The Brain of Diemyctylus Viridescens 303

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33-

56.

EXPLANATION OF PLATES.

ABBREVIATIONS.

a.——aula.
ap.—auliplexus.
ar.—arachnoid.

5.—bone.
6. v.—blood vessel.

c.—cartilage.
cal.—-callosum.
cb.—cerebellum.

c. e.—callosal eminence.
cer.——cerebrum.
ch.—chiasma.

cm.—cerebral commissures.

cr.—crista.

dc.—diaccele.
Dien.—diencephal.
dp.—diaplexus.
du.—dura.

é.—endyma.
ec.—epiccele.
Epen.—epencephal.
ep.—epiplexus.
ept.—epiphysis.

gl.—intermaxillary gland.
gm.—geminum.
gn.—ganglion.
gs.--gasserian ganglion.

hb.—habena.
Ap.—hypoarium.
hy.—hypophysis.
tnf.—infundibulum.
?.—lophius.

mc.-—mesoccele.

md,—medulla.
Mesen.—mesencephal.
Meten.—-metencephal.
mp.—mesoplexus.
mic.—imetaccele.
mip.—metaplexus.
mtpr.—_metapore.
mu.——mucosa.
my.—myel.
myc.——myeloccele.

n.—nostril.
ac.—notochord.

olf.—olfactory lobe.

p.-—porta.
par.—paraphysis.
pe.—paraccele.
pcm.-—precommissure,
pi.—pallium.
pocm.—postcommissure,
pp.—paraplexus.
pr.—pvreoptic recess.
Prosen.—prosencephal.
prc.—prosoceele.

rc.—rhinoccele.
Rhinen.—thinencephal.

S¢.—-saccus vasculosus.
scm.—-supracommissure,
si.—-sulcus.

sp. -—supraplexus.
s¢.—striatum.

sl. cm.—Sylvian commiissure.

7.—terma.
th.—thalamus.
¢ty.—torus.

Roman numerals I to XII indicate the cranial nerves.

GENERAL DESCRIPTION.

The general views of the brain, including the mesal aspect, are
reconstructed from camera lucida drawings of transections cut through
the entire head. These reconstructions were corrected, as far as possi-
ble, by comparison with camera lucida drawings of both frontal and
sagittal sections through the head. The details were in all cases studied
with higher magnification than was used in drawing. Some of the sec-
tions shown were cut a trifle obliquely, and were chosen because slight
differences in level often exhibit transitions of form and structure which
are instructive.

No attempt has been made to accurately define the limits of the five
segments, because several of the questions of homology involved are
still unsettled. The general arrangement of the cells is represented but
with no attempt to show accurately their size. The membranes, dura
arachnoid, pia, blood vessels and capillaries are usually shown at the
left, the right of the brain being free. The skull, for lack of space, is
not represented.

The magnification of each figure is given in the explanation.

PLATE I. FRONTISPIECE.

From photomicrographs taken by Simon H. Gage.

Fic. 1. Frontal section of the head of a large red Diemyctylus viri->
descens at the level of the porta. X10. It shows the brain cavities as
continuous from myeloccele to rhinocceles, the extent of the cinerea,
and more indistinctly the plexuses. Owing to the hardness of the lens
it could not be cut and the eye was torn in its removal (cf. Fig. 35-40).

There appears a trace of the intermaxillary gland and latero-caudad
of the ear a deeply stained mass the nature of which is not known but
which is found in all post embryonic stages examined (cf. Fig. 40).

The angles in the cephalic cavities show the caudal limits of the
rhinocceles. The portze are wide, a horn of cinerea, probably repre-
senting Ammon’s horn (p. 263) extends latero-caudad from each while
directly caudad are the white masses, the dorsally directed columns of
the callosum.

Between the cephalic part of the ear and the brain, the open space is
part of the endolymphatic sac and the lateral recesses of the epiccele
come into close contact with this sac.

Fic. 2. A similar section from a larval diemyctylus I cm. long. X 50.
Coutrast the small relative amount of alba, the membranous mesal
walls of the cerebrum, the wide dia- and mesocceles, the extreme
cephalic and lateral extension of the lateral recesses of the epiccele,
and the fact that no trace of columns of the callosum can be seen. (cf.
Fig. 69, 71). The level of the section is shown at 2 Fig. 67.

306 Susanna Phelps Gage

PLATE II.

FIG. 3-5. Reconstructions of brain of adult diemyctylus, male, 9 cm.
long. X about17. (cf. Pl. VI). Interrupted lines indicate the extent of
the cavities ; coarse dots, cinerea which appears on a natural surface.
Cinerea is seen on all sides of the olfactory lobes.

Fic. 3. Ventral view. Cinerea marks out the extent of the terma,
a few cells passing ventrad of the cerebral commissure to the chiasma,
and is coextensive on the surface with the cavity of the infundibulum
which is partly covered by the hypophysis. The ganglia at the left
nearly touch. The 8th nerve is more ventral than the 7th and does not
extend so far caudad. The rings on the 2d, 3d, and 4th indicate the
foramens of the skull through which they pass. The geminums are
scarcely visible.

Fic. 4. Dorsal view. Cinerea covers the habenz, the tip of the in-
fundibulum seen ventrad of the 3d, the dorsal side of the epencephal,
with a mere trace at the side of the metaplexus, and at the caudal end
of the geminums. The habene are at a lower level than the cerebrum
and the relative position of supraplexus, including the paraphysis, the
epiphysis and postcommissure is shown, and the metapore is indicated.

Fic. 5. In the cerebrum the relation of the paraccele to the porta and
paraphysis is shown, and in the metaplexus the lateral cavities. The
saccus appears caudad of the cinerea of the infundibulum. The two
origins of the Ist nerve are indicated by dots in concentric lines, of the
other nerves by white. The origins of the 7th and 8th are connected and
a branch of the 7th passes the union dorsad of the 5th toward the gasse-
rian ganglion.

Fic. 6. Mesal view of same. X about 29. The lines at the dorsal and
ventral side with the numbers indicate corresponding figures of Plate
III, the lines at the right and left, the corresponding figures of Plate
IV. A portion of the intermaxillary gland is shown; the pigmented
dura with folds surrounding the paraphysis and supraplexus and par-
tially separating the hypophysis from the infundibulum; the arachnoid
filling the spaces between dura and pia especially in the space between
hemicerebrums ; the pia with vessels extending over mesal face of the
cerebrum, and interrupted with the endyma to form the metapore; the
broad cut surface of the geminumis ; the sulci indicated by deeper shad-
ing of the cavities; the opening of the paraphysis between the auli- and
diaplexus; the oblique porta; the callosum and precommissure with no
cinerea intervening ; and cinerea cephalad of the terma, marking the
caudal progress of the latter (p. 282).

Fic. 7. A nearly mesal section from a sagittal series of adult diemyc-
tylus’ brain, hardened by Golgi’s method, and showing the relations of
the blood vessels with marked distinctness. XX 27. Shows vessels of
the supraplexus passing caudad of the paraphysis to the diaplexus ;
cephalad, to the auliplexus with its caudal extension into the diaceele,
and also to the intercerebral pia with a loop to the crista.

Fic. 8. Transection of brain of half-grown red diemyctylus in region
between 27 and 28 of Fig. 6. X 65. Shows the endolymphatic sac con-
necting by its duct with the ear, the blood vessels surrounding it within
the dura; the mesoccele at its caudal end wider than in the adult (Fig.
26), narrower than the larva (Fig. 84); the relations of the 7th and 8th

i

The Brain of Diemyctylus Viridescens 307

nerve, the 7th continuous with cinerea and also receiving fibers; fibers of
the 8th crossing the meson.

FIG. 9, to. Dorsal parts of transections of the brain of adult diemycty-
lus, stainedincarmine. X 65. Fig. 1ois caudad of 9, at the level between
23 and 24 of Fig. 6. They show the membranes passing dorsad of the
epiphysis, but the vessels of the pia surround it, and do not cross the
meson. The fibers of the postcommissure are mingled with fibers which
apparently arise in the peculiar cells of the roof called torus. (cf. Fig.
59, 60 and p. 266).

Fic. 11. Lateral view of adult diemyctylus, male, nearly natural size,
(16). 1, the pockets at the side of the head (cf. Fig. 40).

Fic. 12. Shows length of the larva, the brain of which is represented
in Plates I and VI.
PLATE III.

A few of the sections from which figures 3-6 were reconstructed.
Their position is shown in figure 6 by corresponding numbers. The
membranes and capillaries are shown at the left, and the position of eye,
ear and nostril indicated. The cinerea is represented by dots. x about
22 (see scale).

Fic. 13. Near the tip of the olfactory lobes, showing the cells ar-
ranged in rows perpendicular to the mesal surface, the first root of
the olfactory nerve I, and the intermaxililary gland.

Fic. 14. Through the second olfactory nerve roots I,. Cells are con-
tinuous from ectal to ental surface.

Fic. 15. Near the boundary between olfactory lobes and cerebrum.
At olf. are cells continuous with those belonging to the olfactory re-
gion ; at ce. the beginning of the callosal eminence; at /. cells which
mark the caudal path of the terma (p. 282), and are just cephalad of the
portae.

Fic. 16. The paracceles are separated only by the crista and a double
layer of endyma, a part of the terma. The striatum is represented by
the part lying between the two lateral projections of cinerea.

Fic. 17. At the level of the portae; the hemicerebrums are united
dorsally only by the pallium with its plexuses.

Fic. 18. The callosum lies between the aula and preoptic recess.

Fic. 19. Shows the lateral columns of the callosum extending to the
cerebral eminence, and the auliplexus caudad of the paraplexuses. The
striatum shows scattered cells connecting the two horns of cinerea.
The caudal horn of the paraccele is fully established by the union of
the mesal and lateral walls of the cerebrum.

Fic. 20. Through the supraplexus and optic nerves II, which extend
cephalad and enter the eye at the level of figure 17.

Fic. 21. Through the opening of the paraphysis. Compare relations
of thalamus and paraphysis with figure 98.

Fic. 22. Through the tip of the cerebrum containing Ammon’s horn.
A recess of the epiphysis expands dorsad of the habenz while ventrad
of them are the sulci continuous with f/ of the next cephalic sections.
The two plexuses appear.

308 Susanna Phelps Gage

Fic. 23. Through the hypophysis, infundibulum and saccus, and
more cephalic portion of the endolymphatic sac.

FIG. 24. Shows the wide dorsal union of the geminums, the layers in
the cinerea, and the relations of the branches of the 5th and 7th nerve
as they pass to the gasserian ganglion.

F1G. 25. Shows the relation of the nerves at the level of the origin of
the 5th and the lateral wing of cinerea extending to the surface of the
epencephal. (cf. Fig. 82).

FIG. 26. Through the cerebellum and 4th nerve, shows the relation of
the lateral recesses of the epiccele to the endolymphatic sac.

FIG. 27. Shows the cavities of the metaplexus and their relation to
the endolymphatic sacs which meet near the meson.

Fic. 28. The process of a bone upon the meson is surrounded by
dura and overlies a much constricted portion of the plexus, the medulla
approaching the dorsimeson in the vicinity of the 1oth nerve. (ef.
Fig. 93 7). The ganglion of the roth is partially divided, the more
dorsal portion receiving the 9th nerve.

Fic. 29. Section cephalad of the metapore.

Fic. 30. At the metapore.

Fic. 31. Caudad of the metapore.

FIG. 32-33. Show the rapid flattening of the myel.

Fic. 35. From another series. Shows a dorsal union of the endolym-
phatic sacs, at the level of figure 27.

PLATE Iv.

Fic. 35-40. Frontal sections of the brain of an adult, male, diemycty-
lus 7.5 cm. long, stained in haematoxylin. At the level shown by corre-
sponding numbers in figure 6. X about Io.

FIG. 35. Dorsad of the porte, shows the arrangement of pockets in
the metaplexus (p. 267) and the change of direction in the rhino- and
paracceles.

Fic. 36. Shows the relation of the cavities here interrupted by the
caudal wall of the geminums.

FIG. 37. Shows the ventral dip of the rhinoccele.
Fic. 38. Shows the crista and the relative position of nerves.
FIG. 39. The nerves are a composite from three sections.

Fic. 40. Shows the base of the brain in relation of the parts of the
left side, including 1, 2, 3, the pockets from the skin which develop in
the adult male (Fig. 1) and receive branches of the 7th. a (Fig. 1)
au unidentified body.

Fic. 41. An enlargement of Fig. 35. XX about 60. Shows the rela-
tion of the two roots to the olfactory nerve, a branch of the 5th cross-
ing it on its way to the intermaxillary gland; the relation of pia to the
nerve roots ; the continuity of ectal and ental cinerea from the tip of
the rhinoccele ; the scattered cells of the callosal eminence.

The Brain of Diemyctylus Viridescens 309

Fic. 42. An enlargement of the next dorsal section from Fig. 36. X
60. The ventral curve of the callosum between the two pillars is sup-
plied from a section from another series which was thicker. Shows the
relation of the intercerebral pia; the vessels of the auli- and paraplexuses ;
the portze and Ammon’s horn ; two layers of cinerea in the thalamus.

Fic. 43. An enlargement of Fig. 37. X about 32. The nerve tract
is a composite from two sections and shows a bundle from the myel
giving off a few fibers to the rith nerve, the rest continuing cephalad
as the ascending solitary bundle. The relations of the 7th and 9th to
the pia are shown.

Fic. 44. An enlargement of Fig. 39. X 32. Shows the origin of the
3d nerve and of fibers from the same region which unite with the 5th
nerve, also the commissure of the 3d.

Fic. 45, 46, 47. Frontal sections through the ventral, middle and dor-
sal parts of the crista, show the fibres and loop of vessels which it con-
tains. X 125. Near the level of figure 38.

Fic. 48, 49. Frontal sections through the crista and part of the fornix
of the cat. 49, is through the larger portion of it, and 48 through the
more ventral part which continues as a slight ridge from it. The direc-
tion of rows of cells is indicated by dots. A blood vessel penetrates
nearly to the crista. X 6

Fic. 50. A frontal section more ventral than Fig. 40, through the
infundibulum, saccus and portion of the hypophysis to show the
membranes.

PLATE V.

Fic. 51. Transection of the brain of an adult, male diemyctylus, 5.3
em. long, stained in carmine. X 125. Near the level of 18, Fig. 6.
Shows the callosum and two parts of the precommissure separated by
cells ; at /, fibers cut transversely which may represent a fornix as they
can be traced cephalad of the portae; the paraphysis cephalad of its
opening into the cavities ; loops of capillaries penetrating even so far
as the callosum ; and processes from the brain substance toward the pia.

Fic. 52. A nearly median, sagittal section, of the roof of the dien-
cephal of an adult, female diemyctylus, 10 cm. long. X 125. Shows
the paraphysis; the epiphysis with a few fibers from its caudal end ;
the supracommissure with processes from the endymal cells extend-
ing into it; and the transition of these cells, to those of the diaplexus.

Fic. 53. An enlargement of the paraphysis and its union with the
cavity as seen in Fig. 21. XX 125. Shows. the pigmented dura, the
vessels of the supraplexus, and the endyma of the pallium.

Fic. 54. A frontal section of a large (7 cm. long) red form. XX 120,
From the dorsal part of the metaplexus to show the lack of continuity
in endymal cells at its caudal end (cf Fig. 55).

Fic. 55. Part of atransection from an adult female, 7. 7 cm. long,
corresponding in level with 30 Fig. 6, to showthe metapore. X 120. The
endyma is recurved and covered by a granular matter at the opening.
The pia with vessels ceases, the dura is lined throughout by arachnoid
cells. (cf. Fig. 30).

Fic. 56 A more caudal part of the same section as Fig. 52 to show
the metapore near the meson. X 120.

310 Susanna Phelps Gage

Fic. 57. Transection of the medulla of a larval diemyctylus, 16 mm.
long, near the level of 88 Fig. 67. X 27. Two or three cells from the
endyma are lacking at the metapore (cf. Fig. 55).

Fic. 58-60. Parts of frontal sections from the same series as Fig. 35.
See 60 Fig. 6. X 125. Fig. 58 shows the epiphysis cephalad of which is
the cinerea of the habenz, and caudad are blood vessels. Fig. 59 shows
the paraphysis surrounded by vessels of the supraplexus, dura arach-
noid and pia; the supracommissure connecting the habene ; the post-
commissure with fibers from the cells of the ‘‘torus.’’ Fig. 60 is ventrad
of 59.

Fic. 61. Part of a transection of the brain of an adult, female, die-
myctylus 11.5 cm. long, from the dorsal part of the geminum (cf. Fig.
25), prepared by Golgi’s method. X 120. Shows the fine filaments +
from the brain surface extending toward the pia; cells among the fila-
ments with processes into the alba; processes connecting with
endymal cells and cells scattered in the alba, and separating the cells
of the cinerea in rows. These are a few selected fibers from the mass.
In some cases fine processes apparently counect the ectal and ental set
of fibers.

Fic. 62. A part of a frontal section enlarged from + Fig. 69. XX 500.
Shows a blood vessel between the cerebrum and thalamus with fila-
ments + extending to the vessel.

PLATE VI.

As in Plate II cinerea extending to the surface is shown by dots,
upon cut edges, by cells; interrupted lines indicate extent of cavities.

Fic. 63-65. Reconstructed views of the brain of a larval diemyctylus
10 mm. long (Fig. 12), and 2-3 days after hatching. X 56.

FIG. 63. Ventral view (cf. Fig. 3), shows the great breadth of the
brain in the region of the epencephal, completely hiding the mesence-
phal; the small hypophysis; the deeply lobed gasserian ganglion, and
the separation of the ganglia of the 7th, 8th, 9th, and roth nerves.
The 6th is somewhat exaggerated in size, and a nerve is shown caudad
of 12th, probably the Ist spinal.

Fic. 64. Dorsal view (cf. Fig. 4) shows the short cerebrum overhung
by the habenz ; the relatively large diencephal and mesencephal; the
extensive areas of cinerea; the cephalic projection of the epencephal
with its membranous roof, ef; the caudal expansion of the mesoccele.

Fic. 65. Lateral view (cf. Fig. 5). The origin of nerves is left white ;
shows the comparatively ventral position of 5th and 8th, and the long
axis of the porta extending cephalo-caudad with the paraphysis open-
ing at the caudal margin.

Fic. 66. Part of a sagittal section of the head near the meson of a
larval diemyctylus, 12 mm. long. X 60. Shows the relation of the para-
physis to the plexus and the commiissures (cf. Fig 7); the small amount
of tissue between the brain and the skin and mucosa.

Fic. 67. Mesal view of same as Fig. 63. X 130. (cf. Fig. 6). Shows
the large aula, the small cerebral commissures, ca/, pcm; the unde-
veloped supraplexus ; the paraphysis, pushed cephalad by the habene,
the endymal character of the roof of the mesencephal with a more

oa
ie a

The Brain of Diemyctylus Vtridescens 311

lightly shaded portion of the geminum (gm.) which approaches the
meson ; the small cerebellum ; the simple metaplexus ; and the ap-
proximation of the hypophysis and notochord. The space between the
medulla and pia may not be natural. The numbers refer to the cor-
responding figures of other plates.

Fic. 68. A more nearly mesal section of the same series as Fig. 66 to
show the persistent opening of the epiphysis and its relation to the
commissures. XX 120. The habena is seen in face view.

Fic. 69. Frontal section of the same series as Fig. 2 at the level
shown in Fig. 67. Shows the two roots of the olfactory nerve; the
undifferentiated form of the rhino- and paracceles; the caudal expan-
sion of the mesoccele.

Fic. 70. An enlargement of Fig. 69 to show the paraphysis and dia-
plexus. X 120.

Fic. 71. A section ventrad of Fig. 69. At ec the mesal cells are at
a more ventral level. Shows the cephalic extension of the aula.

Fic. 72. An enlargement of the crista of Fig. 71. x 120.

Fic. 73. A transection through the head of an embryo of 12 days, to
show the cephalic flexure and the position of the paraphysis. X 4o.

Fic. 74. A more caudal section than Fig. 73. Shows the crista, the
cavities, and the small amount of alba.

PLATE VII.

Transections of the brain of a larval diemyctylus from which Fig. 63-
67 were reconstructed, at the level of the corresponding numbers of
Fig.i67. X 65.

Fic. 75. Through the olfactory nerves.

Fic. 76. The section cephalad of the porte, shows the extent of the
terma, (cf. the cinerea on the mesal view at this level, Fig. 67).

Fic. 77. Shows the remnants of the double fold of terma, the more
ventral of which is the crista.

Fic. 78. Shows the porte, the plexuses, the cephalic part of the ha-
benz, and the tube of the paraphysis.

Fic. 79. A part of a section between Fig. 77, 78 to show the cephalic
enlarged part of the paraphysis and its relation tothe membranes. The
dura does not extend around it as in the adult. x I50.

Fic. 80. Shows the dia- and auliplexuses and the sulcus opposite the
latter which passes into the infundibulum.

Fic. 81. Shows the close approximation of the geminums at the dor-
sal side and the infundibulum, composed of cinerea.

Fic. 82. Shows the cephalic prolongations of the lateral recesses of
the epiccele and the three parts of the gasserian ganglion.

Fic. 83. Shows the cephalic parts of the cerebellum which do not
unite at this levei across the meson.

Fic. 84. Shows the caudal expansion of the mesoccele, a trace of
alba in the cerebellum and a few cells at the origin of the 4th nerve.

TS
)

312 Susanna Phelps Gage

Fic. 85. Shows the origin of the 6th nerve caudad of the 8th, and
what is rare at this stage of growth, several capillaries entering the
brain close together.

Fic. 86. Through the roth nerve and ganglion and a part of the sul-
cus from which the 9th nerve passes off.

Fic. 87. Shows the 11th nerve and y a bundle of fibers which can be
traced for some distance in the medulla.

Fic. 88. Shows the origin of the 12th nerve.
Fic. 89. Shows the beginning of the myel and a nerve root.

Fic. 90. An enlargement of the dorsal part of Fig. 80. Shows the
epiphysis and the dorsal enlargement of the diaccele ventrad of it. xX
150.

Fic. 91. An enlarged section between Fig. 78 and 80, to show the
supracommissure, the rudiment of the callosum, the opening of the
paraphysis ventrad of the diaplexus. XX 150.

Fic. 92. An enlargement of the lateral part of Fig. 84, to show the
origin of the 7th and 8th nerves, and part of their ganglia, the 7th is
continuous at its dorsal part, with cells of cinerea which form a ‘‘ Rau-
tenlippe’’ or sulcus. A blood vessel extends among the fibers of both
the 7th and 8th. X I50.

PLATE VIII.

Mesal view of the brain of a small Amia calva, reconstructed
from transections, of which Fig. 94-100 area few. X about 6144. Mesal
views by Goronowitsch (21), of Acipenser ruthenus, by Herrick (24),
and Wilder (50), of lepidosteus differ somewhat from this though there
is a general agreement. The pia is shown as extending from the auli-
plexus between the olfactory lobes, and on the dorsal part of the gemi-
nums. It is not shown on the ventral side at all. The opening into
the rhinoccele is not calleda porta. Nounion except the terma between
the hemicerebrums occurs until the commissure cm. From the infun-
dibulum a cavity extends cephalad (Fig. 98), and four caudad (Fig. too),
The paraphysis and epiphysis open into the cavities (Fig. 98-99) and
the latter at the usual place between supra- and postcommissures. The
geminums unite by a commissure which is depressed below the dorsal
limit (Fig. 100), and form a caudal recess over the valvula. The
metaplexus extends as a pocket over the cephalic end of the myel, z,
in a region comparable to the metapore. At # the dorsal walls of the
medulla nearly meet. The endymal surface is shown marked by sulci.

FIG. 94-100. Transections of same. XX about 744. The endyma is
represented by a chain of cells, the cinerea by dots; the larger blood
vessels penetrating the brain are shown.

Fic. 94. At the right the rhinoccele is completely circumscribed, at
the left is just closed off from the sulcus vc of Fig. 95. The pallium ex-
tends to the extreme lateral border and by a fold on the meson forms
two paracceles.

FIG. 95. The mesal fold of Fig. 94 is separated into the auliplexus
and crista.

Fic. 96. An enlargement of the crista of Fig. 95. XX 22. There is no
enlargement of the brain at this point except by endyma. The fibers
in the crista are like those in the membranes.

Fic. 97. Shows the union of hemicerebrums by the commissure cm.
At the left are indicated the capillaries which extend as a network
throughout the brain substance to the endyma, Contrast Fig. 1o1. At

The Brain of Diemyctylus Viridescens a1

the right interrupted lines represent the cerebrum raised to an upright
position and the pallium folded to form a paraplexus v.

Fic. 98. Shows the infundibulum with the hypophysis surrounding
the cephalic extension ; the pallium passing at the right from the sul-
cus s/ laterad and giving off the paraphysis, or dorsal sac, in which is
embedded the epiphysis at the left of the meson.

Fic. 99. Shows the caudal projection from the paraphysis over the
supracommissure and habene, and hence the manner in which cinerea
surrounds the habena; and the sulcus ventrad of the habena which is
continnous with s/ of Fig. 98.

Fic. 100. Shows the union of the geminums and the relation of the
caudal extensions from the infundibulum.

Fic. ior. A transection of the brain of a large red diemyctylus, be-
ginning to transform. X 22. Through the precommisure, near the
level of Fig. 17 but shows the hemicerebrums much divaricated as is usual
with the red forms. At the right, interrupted lines indicate the position
of the cerebral walls, as though raised and carrying the plexus with
them (cf. Fig. 97).

FIG. 102. The outline of a transection of the brain of a young lepi-
dosteus, at a level corresponding with Fig. 97, copied from Wilder (50).
This shows that in a young ganoid the cerebral walls occupy practically
the same position as indicated by the interrupted lines of Fig. 97.

Fig. 103. A view of the cephalic half of the brain of a larval lamprey,
12 cm. long, from the morphological meson. X about 4o. From the
great development of the right habena (Fig. 107) the mesal parts are
pushed to the left. The epiphysis and its stalk are shown as mesal
structures. The pigment shown here as black is really a brilliant white
by reflected light. The supra- and postcommissures are elongated
structures, the mesoplexus sends a diverticulum cephalad over the lat-
ter (Fig. 109). The rhinoccele extends cephalad, the paraccele caudad
from the common opening shown as deeply shaded. The precommis-
sure is dorsad of the porta (Fig. 104). Another band of alba at cm.
corresponds in position (Fig. 105), with reference to the chiasma, to
em. of Fig. 93. The infundibulum has a cephalic and caudal prolonga-
tion, with the former is associated the hypophysis. The optic nerve
extends caudad to the eye.

Fic. 104-111. Transections of the same. X 40.

Fic. 104. Through the epiphysis, its stalk, the paraphysis (p. 285)
and the tip of the left habena which protrudes into it.

Fic. 105. Through the porte, the pallium and the opening of the
paraphysis. st indicates a possible striatum.

Fic. 106. Through the cerebrum and the habenz, to show the relation
of the pallium to the latter.

Fic. 107. Through the habenze and supracommissure near the point
where the stalk of the epiphysis opens into the diaccele.

Fic. 108. Shows the membranous roof of the mesencephal, the meso-
plexus with a mesal fold and the sulcus s in the walls of the geminum.
The large cell at 0 forms aridge. In this and similar ridges the large
cells are arranged.

FIG, 109-110. Portions of enlarged sections through opening of the
epiphysis and the postcommissure and cells of the torus.

Fic. 111. The dorsal part of a section just cephalad of the closure of
the myel to show a minute sac of endyma, in the position of a metapore.

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A BACTERIAL STUDY OF ACUTE CEREBRAL AND
CEREBRO-SPINAL LEPTO-MENINGITIS.

HERMANN MICHAEL BIGGS.

While the infectious nature of Cerebral and Cerebro-Spinal
Lepto- Meningitis has been long recognized, the character of
the micro-organism or micro-organisms producing these affec-
tions has not been satisfactorily determined. ‘The present bac-
terial study undertaken at periods when these diseases were
prevalent in New York may throw some additional light on
this question.

The facts at hand at least clearly demonstrate that a vari-
ety of pathogenic bacteria may be found in the meningeal
exudate of both cerebral and cerebro-spinal meningitis, and
that these bacteria are probably the important etiological fac-
tors in these diseases. "The investigations thus far made do
not confirm the assumption that epidemic cerebro-spinal
meningitis is caused by a specific organism.

Most of the observations here detailed were made upon
cases which occurred during the eight weeks ending May rst,
1892 and the same period in 1893. During this period for the
past two years meningitis in adults has been relatively fre-
quent in New York. ‘The observations have almost without
exception been made on adults. It is also during the same
period (March and April), as the vital statistics show, that
the mortality is highest from acute lobar pneumonia, and it is
to this disease that lepto-meningitis both cerebral and cerebro-
spinal seems most closely allied in its etiology.

In this study only those cases will be considered which were
characterized anatomically by an acute suppurative exuda-
tion in the pia, not caused by the tubercle bacillus.

The cases of acute cerebral and cerebro-spinal meningitis
have been grouped together, because neither from an anatom-
ical nor etiological standpoint are there sufficient grounds for
separating them.

316 flermann Michael Biggs

It is further the opinion of the writer that many of the cases
of cerebral meningitis would prove to be of the cerebro-spinal
type at the autopsy, if the spinal cord were removed and ex-
amined. In the usual routine of autopsy work, owing to the
time and labor involved, the spinal cord is not removed, un-
less there have been some symptoms pointing to disease in
the spinal canal. The operator examines the portion of the
cord accessible from the cranial cavity, and in the absence of
gross evidences of disease here the remainder is not removed.
As a matter of experience the writer can affirm that there is
not infrequently an abundant exudation in the dorsal and
lumbar portions of the spinal pia, when the cervical portion is
free, and when the clinical history has given no indication of
the involvement of the spinal meninges.

In the present series there are eighteen cases, of which six
were cases of cerebro-spinal and twelve of cerebral lepto-men-
ingitis. In only three of the series was the meningitis secondary
to traumatism or to disease of the cranial bones or soft parts
about the head. Of the cerebral cases one was primary and
eleven were secondary to some local or general acute infec-
tious process. A more or less complete bacterial examination
was made in seventeen of the cases.

There has been a general feeling among medical writers
that acute cerebral lepto-meningitis in adults is very common-
ly secondary to otitis media or disease of the soft parts about
the head or cranial bones. ‘These cases do not wholly confirm
this view. In only two was the inflammation of the pia second-
ary to an otitis media and in one probably to a scalp wound.
In the other cases the disease occurred primarily or was sec-
ondary to some general infectious disease. In the twelve cases
of acute cerebral lepto-meningitis, the bacterial examination
gave:

In one case pure cultures of the axzthrax bacillus ;

In one case the Bacillus coli communis ,

In one case the B. coli communis with Proteus vulgaris (the
latter was probably due to a contamination).

In four cases the Pxeumo bacillus of Fraenkel ;

In two the Streptococcus pyogenes ;

A Bacterial Study of Acute Meningitis 317

In one the Dzplococcus intracellularis meningitidis ;

In two cases a mixed infection.

Some brief notes of the clinical histories and pathological
findings in the more interesting cases follow.

CASES OF CEREBRAL LEPTO-MENINGITIS.

CasE I.—Acute Lepto Meningitis due to the Diplococcus Intra-
cellularis Meningitidts.

H. T., male, aet. 28, was found in a lodging house, and no
history could be obtained, excepting that he had been ill for
several days. On admission, he was stupid, gave his name
but would answer no other questions. ‘There were twitchings
of the muscles of the face, and rigidity of the muscles of
arms and neck. ‘This rigidity of the muscles appeared as if
it were partly voluntary, and the condition seemed cataleptic.
When the arms were raised they remained in the position in
which they were placed for some minutes. The reflexes
were increased and the skin hyperaesthetic. He would not
swallow any fluid, and spit it out when it was poured in his
mouth. His condition did not seem to be very serious, but
36 hours after his admission his pulse began to grow rapid,
his temperature rose to 103 F., the respiration increased in
frequency, and 12 hours later he died.

Autopsy :—There was hyperaemia of all the abdominal and
thoracic organs, and the pia covering both the convexity and
the base of the brain contained an abundant fibrino-purulent
exudation. Cultures made from this exudate showed the
diplo-coccus intra-cellularis meningitidis of Weichselbaum.

CaAsE II.—Acute Lepto-Meningitis due to the Anthrax Bacillus.

T. H., wool-sorter, aet. 36. The history shows that about
three days before admission to the hospital he noticed a
pimple on the left wrist ; this became vesicular, opened and a
very dark areola formed around it. His arm began to swell
rapidly, and became very dark in color and extremely pain-
ful. He had no chill and complained of no fever. During
this time he was treated at Bellevue Out Door Dept. with

318 flermann Michael Biggs

local applications. On admission the left arm was enormously
swollen and showed extensive hemorrhages into the skin and
subcutaneous tissue. There was a small elevated abraded
point on the wrist with a hemorrhagic areola; temperature
varied from 101 to 104; pain was severe. Under treatment
the swelling diminished, the pain almost disappeared ; he slept
well and felt well and wanted to sit up. On the third day af-
ter his admission at about 3 p. m. he complained of pain and
heat in his head. One hour later he became delirious, his
temperature rose to 106 F. He grew rapidly worse, and died
18 hours after the appearance of the first cerebral symptoms.

Autopsy :—Arm enormously swollen, with blebs over wrist
and extensive hemorrhages into skin and subcutaneous tissue.
The blood everywhere in the body was completely fluid and
dark colored. The spleen was very large and soft, and the
other abdominal and the thoracic organs were congested.
The pia mater of the brain over both the convexity and the
base was studded with hemorrhages, and the meshes of the
pia both in the fissures and over the convolutions were dis-
tended with sero-pus. Cultures were made from the fluid in
the subcutaneous tissue from various portions of the wrist and
arm, from the heart blood, the spleen, and the pial exudate
on both sides of the brain. In all of the tubes inoculated
from the brain, a pure culture of the anthrax bacillus devel-
oped. All of the other tubes remained sterile. The media em-
ployed and the conditions under which the cultures were made
and kept after inoculation were thesame. ‘The identity of the
anthrax bacillus was established by microscopical examina-
tion, by culture reaction and by inoculation of animals.

Cover-glass preparations were also made from the fluid in
the subcutaneous tissue of the arm, from the spleen and the
blood contained in the heart cavities. No organisms were
found microscopically in these situations.

It is hardly necessary to direct attention to the extraordi-
nary character of the localization and the findings in this case,
and there seems to be no satisfactory explanation to offer to
account for them. ‘The results are stated as obtained, and
their accuracy vouched for.

A Bacterial Study of Acute Meningitis 319

Case IIlI.—Acute Lepto-Meningitis following Typhoid fever,
due to the Bacillus Coli Communis.

Male, laborer, aet, 27, admitted March 26, 1892. He had
been feeling unwell for about three weeks previous to admis-
sion. For the first week after admission temperature ranged
from 100 in the morning to 105 in the evening, and April 1st
dropped to normal in the morning with only a slight evening
elevation. April gth it remained normal throughout the
day. On April rath it rose to 102;%5 and remained somewhat
above normal until the morning of the 18th, when it com-
menced to rise gradually, and on April 2oth reached 105. He
then began to have a low muttering delirium. During the
next week the temp. ranged between 102-105;75- On April
27, 28, and 29 he had quite severe hemorrhages from the
bowels and his pulse became rapid and feeble. During these
and the following days the delirium continued ; neck became
somewhat rigid, and he gradually grew weaker, and died on
May 2d.

Autopsy :—There were found at the autopsy extensive old
but unhealed typhoid ulcerations in the lower part of the ileum
and an acute lepto-meningitis with a moderately abundant
sero-purulent exudation over both the base and convexity of
the brain. ‘The ventricles were distended with serum contain-
ing a little fibrin and pus.

On bacteriological examination this exudation was found to
contain pure cultures of the Bacillus colt communis.

In this case organisms (Bacillus coli communis) normally
present in the intestinal contents had found entrance through
the ulcers in the intestines into the blood or lymp currents, had
made their way to the cerebral pia and set up there an acute
inflammation. ‘This is the first case recorded of a meningitis
caused by this organism.

Case 1V.—Acute Lepto-meningitis, (Otitis Media, etc.) due toa
Mixed Infection.
G. B., aet. 55, laborer, was admitted April 11, 1892. The
history given was that he became unconscious while return-
ing home from work and was brought by an ambulance to the

320 Flermann Michael Biggs

hospital. Temp. at time of admission 102,55, P. 76, R. 18.
He soon regained consciousness, but seemed nervous and
stupid. He complained of no headache nor pain in neck or
extremities. ‘There was a foetid discharge from the left ear, and
his tongue was dry, brown furred and tremulous. His temp.
ranged from 102-103;%; during the next three days, pulse from
80-90, resp. 16-25. Rigidity of the neck developed on the day
following his admission and gradually increased. On the
second day he became stupid and difficult to arouse and
seemed to have some loss of power on the left side. On April
14th he became comatose. On April 15th the temperature varied
from 102-103, the respirations became rapid and superficial (30-
40) and the pulse 100 to 130. Operation was advised in hope
of finding a cerebral abscess and relieving pressure by evac-
uation of the pus. An operation was performed by Dr. J.
D. Bryant. The skull was opened above and posterior to
left external auditory meatus ; the dura was found free from
inflammatory exudate but with only slight pulsation, and the
convolutions under it seemed flattened and the brain substance
rather soft. An aspirating needle was passed into the lateral
ventricle and about 7 ounces of slightly blood stained fluid
withdrawn. Pulsation of the dura became much more marked
after removal of the fluid. A small drainage tube was then
inserted into the lateral ventricle, and the external wound
closed. He rallied very little from the operation and died
about 7 hours afterward.

Autopsy :—An abundant fibrino-purulent meningitis was
found at the base. The pia of the convexity was not affected.
The ventricles were much dilated with blood stained serum,
and the ependyma was granular and thickened. There wasa
miliary tuberculosis of both lungs. The prostate contained
a large abscess which had ruptured into the peritoneum and
then became encapsulated. There was also extensive tuber-
cular ulceration in the ileum.

The bacteriological examination in this case showed the
presence of a mixed infection. The Staphylococcus pyogenes
aureus was among the organisms found. Notwithstanding
the extensive tuberculosis of other organs the meningitis was
not of tubercular origin.

A Bacterial Study of Acute Meningitis 321

Case V.—Streptococcus Septicemia, (Acute Double-Pleuritis,
Pericarditis and Meningitis, Rupture of the Spleen), due
to the Streptococcus Pyogenes.

J. M., aet. 41, sailor, was admitted April 6, 1892. The his-
tory given showed that he had been suffering from cough, ac-
companied by an irregular type of fever with frequent chills for
about two weeks previous to admission. He was markedly
alcoholic when admitted; temperature 1o1, pulse I1o0, res-
pirations 26. The following morning, T. 104;%;, P. 108. Phy-
sical examination showed the presence of abundant subcrepitant
and small mucous rales to be heard over both lungs, most
marked over the left upper lobe. The temperature gradually
rose to 105,85, at 11 p. m., P. 112, R. 30. He was delirious and
unable to swallow, and his respirations were rapid and labored.
Under stimulants and antipyritics the temperature dropped to
10375 at t p. m., on April 8th ; the rales had diminished, the
respirations were easier and the delirium less marked. Atg
a.m., April 9th, Temp. 102;5; P. 102, R. 26, and nurse re-
ported that he was much improved, the delirium had disap-
peared and he was able to take nourishment by mouth. At
9.45 a. m. he was seized with an attack of vomiting and
partly raised himself up in bed, when he became suddenly pale
fell back unconscious and died a few minutes later.

Autopsy :— A large amount of fluid and partly clotted
blood was found in the peritoneal cavity. On careful search
for the source of this hemorrhage, a rupture was found in the
lower internal surface of the spleen about one inch and a half
in length. The spleen was large, soft and contained numer-
ous hemorrhagic infarctions. ‘There was also an acute inflam-
mation of the pleura on both sides, of the pericardium and of
the pia of the brain attended with an abundant sero-fibrino-
purulent exudation.

Bacteriological examination showed the presence of the
Streptococcus pyogenes in pure form in the spleen and pial exu-
date. In the blood from the heart there were some other or-
ganisms associated with it. This was undoubtedly a case of
streptococcus septiceemia, and was probably such from the be-
ginning, although the diagnosis during the two weeks illness
before admission to the hospital had been malarial fever.

322 Flermann Michael Biggs

The simultaneous involvement in an acute inflammation of
so many of the serous membranes is of rare occurrence. Rup-
ture of the spleen is described in most text-books as occurring
in several diseases. In a rather large pathological experience,
however, the writer has never seen any other instance of spon-
taneous rupture of the spleen.

Cases VI To IX INcLUSIVE.—Acute Lobar Pneumonia with
Acute Cerebral Lepto-Meningitis due to the Pneumobacillus
of Fraenkel.

The cases of acute lobar pneumonia associated with second-
ary meningitis were four in number. The meningitis affected
both the convexity and base in all the cases. In three of
these, cultures made from the meningeal exudate showed the
presence of the pneumo-bacillus of Fraenkel in pure form.
In the fourth case, unfortunately, no bacteriological examina-
tion was made, but there is no doubt that it was quite similar
to the other cases. The clinical history of these cases differs
from that of pneumonia uncomplicated by meningitis only in
the more pronounced character of the cerebral symptoms after
the third or fourth day, z. e., delirium, rigidity of the back of
neck, muscular twitchings, contracted pupils, etc., and the
higher average range of temperature.

Attention is also directed here to the occurrence of acute
primary lepto-meningitis due to the pneumo-bacillus of
Fraenkel, the lungs not being involved. This organism is
more frequently found than any other, as the causative agent
in cerebral and cerebro spinal meningitis.

CASES OF CEREBRO-SPINAL LEPTO-MENINGITIS.

During the period referred to, 14 cases of cerebro-spinal
meningitis occurred in the writer’s service in only 6 of which,
however, were bacteriological examinations made. In three
of these six cases, the cultures remained sterile; in one the
pneumococcus of Fraenkel developed; in one the staphy-
lococcus pyogenes ; and in one there was a mixed infection.

The history in most of these cases was that commonly
found in cerebro-spinal meningitis. The temperature range
varied greatly ; in some of the cases running uniformly low,
reaching 103 rarely or not at all, and in other cases running
very high, varying between 104 and 107. The pulse rate was

A Bacterial Study of Acute Meningitis 323

usually rapid before the end. Rigidity or stiffness in the
back of the neck, retraction of the head, contracted pupils, de-
lirium, coma, and incontinence of urine and faeces were uni-
formly present. In a small proportion of cases there was a
petechial eruption on the trunk or on both trunk and extremi-
ties. Albuminuria was almost invariably present, and in one
case there was also glycosuria and haematuria. ‘There was
usually hyperaesthesia of the skin and muscles, and in two
cases well marked opisthotonos. Paresis or paralysis, involy-
ing small groups of muscles or those of one side, was common,
The pupils were contracted, dilated, or irregular. Early
there was increased sensitiveness to light, and later there was
often loss of accommodation and loss of corneal reflex. There
seemed to be no constant relation between the amount of
exudation found after death and the severity or character of
symptoms shown during life. The duration of the cases
which terminated fatally varied between 36 hours and Io or
12 days. In only one clearly defined case of cerebro-spinal
meningitis did recovery take place. In this the temperature
for several days ran between 104° and 106° F.

It has been rare in the writer’s experience to see cases of
cerebro-spinal meningitis at any other season of the year than
during the spring months, and these cases are almost in-
variably primary and develop suddenly without any ascer-
tainable cause.

In several of the cases in which no culture tubes were in-
oculated or in which those inoculated remained sterile, cover-
glass preparations made from the meningeal exudate showed
the presence of diplo-cocci.

Aside from the cases presented in this paperin which a bac-
terial examination was made, during the same period there oc-
curred in the writer’s service nearly 20 other cases of cere-
bral and cerebro-spinal meningitis, including several of
syphilitic or tubercular origin in which there was no bacterial
examination, making a total of nearly 4o cases, most of which
occurred in four months of hospital service. This fact is noted
to direct attention to the prevalence of meningitis at the pe-
riods referred to and to justify the following observations
which have been suggested by the study of this series of cases.

324 Flermann Michael Biggs

1. Purulent or sero-purulent meningitis is always microbic
in origin.

2. Many cases of cerebro-spinal meningitis do not differ
from cerebral meningitis except in the extent of pia affected.
The etiological factor may be the same.

3. Cerebro-spinal meningitis is usually primary.

4. Cerebral meningitis is usually secondary to some in-
fectious disease, and is only occasionally primary.

5. When the disease is secondary the cause of the secondary
infection may bea different organism from that producing the
primary disease.

6. The following organisms have been previously found in
the pial exudate in cerebral meningitis :

. The pneumo-bacillus of Fraenkel.

. The Streptococcus pyogenes.

. The Bacillus Typhosus of Eberth.

. The Staphylococcus pyogenes.

. The Prueumo-bacillus of Friedlander.
f. The Bacillus of ‘‘ La Grippe.””

g. The Gonococcus.

My observations add two more organisms :

i. The Bacillus anthracis.
j. The Bacillus coli communis.

7. The pneumo-bacillus of Fraenkel is the most frequent
cause of cerebral meningitis.

8. ‘The latter organism is a not infrequent cause of primary
cerebral and cerebro-spinal meningitis, the lungs not being
involved.

9. The cases of meningitis due to different organisms do not
show such constant differences from each other in the symp-
toms presented as to make possible the clinical differentiation
as to cause. h

10. The amount of the exudation bears no constant relation
to the severity of the symptoms.

11. It is not possible to distinguish with certainty during
life, cases of acute cerebral hypereemia with or without oedema
from cases of meningitis.

en0m7D

5 West 58th St.,
NEw YorRK CIty,
Aug. II, 1893.

OBSERVATIONS UPON THE EROSION IN THE HY-
DROGRAPHIC BASIN OF THE ARKANSAS RIVER
ABOVE) LITTLE ROCK:

By JOHN CASPER BRANNER.

In October, 1887, I began and carried on for one year a
series of observations upon the Arkansas River at Little Rock,
for the purpose of determining the efficiency of that stream as
an agent of erosion and transportation. These observations
consisted of a series of thirty-two measurements of discharge,
three hundred and sixty-five gage readings, one hundred and
seventy-nine determinations of matter carried in suspension,
and a similar number of determinations of matter carried in
solution by the river water. These observations were so dis-
tributed as to be as comprehensive as possible, embracing all
the varying conditions of weather, temperature and rainfall ;
when the river was rising, when it was falling, when ata
standstill; when low, when high, and whenever there was
any considerable change in the volume or character of the
water.*

Method of Observation.t —A cross-section was carefully meas-
ured 1,200 feet above the upper bridge, a place in the river
where there was least chance of any marked change occurring
within the time occupied by the observations. At the place
selected one bank is of rock and the other of tough clay.
Floats were sent through this section at transverse intervals of
twenty-five to fifty feet, and their positions as they crossed the
section were located by a transit, and the time occupied in

* This paper deals only with such conditions and changes as are pos-
sible in a given section; it does not consider the effects of curves
or varying depths of the channel.

+ The field observations were entrusted to Assistant Chas. E. Taft, an
able civil engineer of wide experience.

326 John Casper Branner

floating one hundred feet was noted. Wooden rods twelve
feet in length were used as floats. These rods were two inches
square at one end, from which they tapered the whole length of
the rod to a sharp point at the other. They were weighted so
as to float upright and to leave the pointed end about two feet
out of the water to serve asa signal. Where the rods could
not be used on account of shallow water, a surface float with a
weight attached by a cord was substituted. From the data
thus obtained the volume of the river was deduced. Sets of
samples of the water were taken along the cross-section at the
time of the velocity observation, each set being in three parts,
one each from the surface, mid-depth, and three feet from the
bottom. In collecting the sample from the bottom, in order
to avoid taking it from the liquid mud usually present next to
the bottom, the collecting apparatus was so arranged that the
sample was taken three feet from the actual bed of the stream.
In order to avoid the possible mingling of the water from low-
er depths with that above, and to insure that the samples fairly
represented the part of the stream from which it was taken,
an open glass tube holding one liter was used for a collecting
vessel. This was so arranged as to close securely by means
of two rubber balls. When a sample was to be taken, the
stoppers were caught back, leaving the ends of the tube en-
tirely unobstructed ; the tube was then sunk by means of a
rod, care being taken to keep its axis parallel with the current
of the stream. By means of a gage the depth to which it
was desired to sink it was determined. When the vessel
reached the desired point, a jerk of the string released the
rubber balls, which closed the ends of the tube and confined
in it a representative of the part of the stream from which it
was taken. The samples were always taken at the time the
volume of the stream was being measured. They were placed
in separate, clean bottles for examination.

In order to determine the amount of matter carried in me-
chanical suspension these samples were all taken to the labo-
ratory and filtered until the water was perfectly clear ; the fil-
ter containing the suspended matter was then dried, and
weighed at the temperature at which it had previously been

Erosion in the Basin of the Arkansas River 327

weighed. The amount of matter in solution was determined
by evaporating the filtered water. These determinations were
made for every sample collected during the year—358 deter-
minations.* A daily record was also kept of the stage of the
river during the time covered by the investigation.

These observations furnish data for the approximate deter-
mination of the discharge of the Arkansas River, and of the
amount of material carried by it, both in suspension and solu-
tion, past Little Rock, during the year in which the observa-
tions were made (1887-8).

Suspended Matter.—The color of the water of the Arkansas
River is due to mineral matter carried in mechanical suspen-
sion. It is more or less muddy all the year round, and even
at its lowest stages, when it carries least sediment, it is not
quite clear. Its color is ordinarily a yellowish brown, but it
sometimes becomes dark red, at which times it carries such a
large amount of mechanical sediments as to render it opaque,
even as seen in an ordinary test tube.

The laws of erosion and transportation naturally lead one
to expect a large amount of mechanical sediments to be re-
moved when the volume of water or discharge is greatest. If
the conditions which supply sediments to the stream were
constant, this would undoubtedly be true, but the conditions are
not constant, and the amount of material moved depends upon
the sediment-supplying conditions rather than upon the trans-
porting power of the water.

The matter in suspension is greatest during a sudden high
rise; but after the water in the stream stands at any high
mark for a few days, the decrease of the amount of suspended
matter it carries is very marked. ‘This contrast is most no-
ticeable during the winter, probably because the frosts loosen
up the surface soil and leave it in a condition favorable for
ready transportation. ‘The amount of sediment carried by the
river varies widely also with the same gage reading at any
stage, being greater with a rising, and less with a falling
river.

* The laboratory determinations were made under my personal direc-
tion by Dr. R. N. Brackett. All the care required by quantitative
chemical analyses was taken with this work.

328 John Casper Branner

The lowest stages of the river are usually during the latter
part of the summer and in the fall of the year. At such times
the water becomes nearly but not quiteclear. "This clearness is
due partly to a decrease in the volume and consequently in
the velocity and carrying power of the water, and also to the
large amount of common salt, lime, etc., in solution in the
water, which substances tend to flocculate and precipitate the
mechanical sediments. The greatest amount of mechanical
sediment found in the water during the year under consider-
ation was 225 grains to the gallon ; this was on the second of
May, 1888, when the river stood at seventeen feet on the gage,
and shortly after protracted rains over the whole or nearly all
the hydrographic basin of the Arkansas River above Little
Rock. It should be added, however, that while this high
water may be taken as a type of the ordinary rises, there are
times when there is but little or no rise, no increase in the
volume of water discharged, but a very marked increase
in the amount of mechanically suspended matter. In Octo-
ber, 1891, occurred one of these so-called ‘‘ red rises’’ of the
Arkansas River, and although the river was quite low—mark-
ing only 3.9 feet on the gage—it carried out 761 grains of
matter to the gallon, of which only 48 grains was matter in
solution. Such a condition of the water is said to be due to
rainfalls on the Canadian River, an affluent of the Arkansas,
which runs through the ‘‘red beds’’ of western Indian Terri-
tory. This illustrates well the fact to which attention has al-
ready been called* that the sediments removed bear no con-
stant relation to the discharge.

The total amount of suspended matter estimated by the
above methods to have been carried down by the Arkansas in
1887-8 was 21,471,578 tons. ‘This estimate, however, must be
regarded as far short of the truth, for the method of taking
the water samples has left out of account that stream of al-
most liquid mud and sand that is pushed along the bed of the

* Annual Report, Chief of Engineers, U. S. A., 1874, I, p. 863 ; 1875,
I, p. 966; 1877, I, p. 433; Physics and Hydraulics of the Miss. River,
1876, p. 417.

Erosion in the Basin of the Arkansas River 329

river at all stages, but especially during high water, and which
adds enormously to the amount of material daily and hourly
carried out of the hydrographic basin of the Arkansas River
above Little Rock.*

Character of the Sediments.—The matter in mechanical sus-
pension in the river water is both sand and clay. Samples
taken from the thread of the stream are mainly of fine sand,
but samples of sediments allowed to settle in the quiet eddies
of the river show that the lighter and more flocculent sedi-
ments sink to the bottom only in the quiet portions of the
water.

An analysis was made of the sediments collected in six
samples of river water of the 11th of April, 1888, two each from
top, middle, and bottom of the stream.

ARKANSAS RIVER SEDIMENT FROM THE STREAM. fF

Sand and insoluble matter, .. 2... 2. 85.18 per cent.
SULT SSCL eo UA a 14.82 a

The soluble portion contained :

Promoxide (REO 1 Suisse ik gi
Alumina, (Ai,0,), SAA REE aa veal ph } 4.96 per cent.

On this occasion the river was very high, standing at 17
feet on the gage, but it had been higher by half a foot two
days before.

A complete analysis was made of the sediment collected
with six litres of water May 2d, 1888, when the river stood at
17 feet on the gage after a sudden rise, and while the rise was
still in progress. It is as follows:

* In the Annual Report of the Chief of Engineers, U.S. A., 1875, II,
p. 478, Col. J. H. Simpson shows how sand-bars travel down-stream.
See also Physics and Hydraulics of the Miss. River, by Humphreys and
Abbot, 1876, p. 147.

t Analysis by Assistant Dr. Jas. Perrin Smith.

330 John Casper Branner

ANALYSIS OF ARKANSAS RIVER SEDIMENT.*

Per cent.

SVT COS C00 me MRE sae rn LUrw erase Mma abe a0 69.53
Adammina(AVO:) 5 oe) as cs fa) Ral fn yma snes 11.65
Tromi(termic) oxide'GNeJO)) 3). cuca vedi funn ce 4.46
Carbonate'of lime (CaCosy i. Ye eee) it ie one 6.62
Carbonate of magnesium (MgCo,) ........ 3.52
Potash (EO) way ay es were ey Toye renee .66
Soda(Na@):./3 2) cosy 6 tet euen ieee oye mia saethee 1.14
Organic and volatile matter). iss. Je Ue 2.95
Totaly ces sy k EDs ee She Te ate oS Be ke 100.58

These analyses, together with a large number of washings
of the sediment, show that its chief constituent is quartz sand.
There is always more or less clay in the water.

The Finer Sediments.—Experiments have already been made
by other observers which show that extremely fine material
held in suspension by water may be retained in suspension for
an indefinite length of time.* The observations upon Ar-
kansas River water point to the same conclusion. A glass jar
one metre in length and holding six litres, was filled with tur-
bid water taken from the river October roth, 1887, and was
allowed to stand in the Survey office until January 16th, 1888.
Within four days after it was filled the water had become com-
paratively clear. Very fine particles continued, however, to
float about in it until January 15th. That night the weather
was cold enough to freeze and feathery ice crystals penetrated
the whole body of the water. As soon as the room was warmed
and the ice melted, the matter in suspension was found to be
collected in masses resembling strings of cobwebs, in which
form it clung to the sides of the jar or sank to the bottom,
leaving the water perfectly clear.

Dissolved Matter.—The matter in solution bears no constant
relation to the volume of water, though in a very general way

* Analysis by Assistant, Dr. J. P. Smith.

{On the subsidence of particles in liquids, by Prof. Wm. H. Brewer,
Memoirs Nat. Acad. Sci., Vol. II, p. 165.

Subsidence of fine solid particles in liquids, by Carl Barus, U. S. Geo-
logical Survey, Bulletin 36, 1886.

Evosion tu the Basin of the Arkansas River 331

it varies inversely with the volume of the water, and ranges
from 11 to 70 grains to the U.S. gallon. ‘This dissolved mat-
ter is principally chlorides of sodium, potassium, and mag-
nesium, and the carbonates of lime, soda, and magnesia. At
low stages of the river there is enough sodium chloride in the
water to give it a decidedly brackish taste. The analyses giv-
en below represent high and low stages of the water.

ANALYSIS OF FILTERED ARKANSAS RIVER WATER.

(Sample collected December 20th, 1888, when the river stood at
nine feet on the gage).

Hypothetical Combination.

Grains per Per cent. of
U.S. Gallon. Solids.

Silber, 4o Bik ie Gaaocercataetaee (SiO,) 75 11.81
Chloride of sodium. . . . (NaCl) 1.96 30.87
Chloride of potassium. . . (KCl) -44 6.93
Sulphate of magnesium . . (MgSO,) .14 2.20
Sulphate ofirom.. . 2 << (FeSO,) 43 6.77
Sulphate of alumina... . . (Al,(S9,),) aE5 2.36
Carbonate ofsoda. .... (Na,CO,) 1.07 16.85
Carbonate of magnesia. . (MgCO,) .28 4.41
Carbonate oflime. .... (CaCO,) Tr 17.80

ME OCAMRMe? ee gl cr WRROR Pe eta tas 6.35 100.00

Found.

Siliicames hee otitis ale (SiO,) 75 11.83
Salpiinide acid). < .. «= (SOy) 51 8.04
Carbonic acid)...30. .'. . (CO) 1.48 23.34
elmore: tan hy a (CL) 1.39 21.92
JGOyTNE Aiea hers le ne a (Fe) .16 2.52
Averaie msi) d 85% eo 0.87 (Al) .02 =R2
(OI) yh ae, ee os (Ca) 45 7.10
ni rey TS cc (Mg) “rE 5.73
MOLASSIFIE C tales Sie is” oe (K) 23 3.63
SIOUIULEE wre pe eva A ee (Na) 1.24 19.57

LEO EE a eg eee Y Bee Sa 6.35 100.00

332 John Casper Branner

ANALYSIS OF FILTERED ARKANSAS RIVER WATER, LOW STAGE.

(Sample collected August 22d, 1888, when the river stood at 2.4
feet on the gage).
Hypothetical Combination.

Grains per Per cent. of
U.S. Galion. Solids.

SUR CoE NC en RO 5 AMD (SiO,) 85 1.83
Chloride of sodium . . . . (NaCl) 28.57 61.58
Chloride of potassium . . . (KCl) .68 1.47
Sulphate of magnesia. . . (MgSO,) 3. 92 8.45
Sulphate oflime..... (CaSO,) 75 1.62
Sil pHarevoticoO selene (FeSO,) 05 Ariat
Sulphate of alumina . . . (Al,(SO,),) .38 82
Carbonate of lime. . . . . (CaCO,) 8.47 18.26

WOtaleys venient vuste nea eee ek eta eran 46.36 100.00

Found.

Sut Yo Ree DM BAP ea eta Poy (SiO,) 85 1.83
Ulli elactdu eae (SO,) 5.90 12173
@arboniciacids cu, awaits (CO,) 5.08 10.96
Ci Fos sho pad ane ise (Cl) 17.62 38.91
TOM Cats mel vatp iol ce toe apn ee ees (Fe) .02 04
AMiabeowwoebol sy BS Gal Go (Al) .06 Fig)
Galera ys oi) alk eos peer (Ca) 3.56 7.68
Magnesite) i. 2) stiaie (Mg) .78 1.68
POLASS UIE ol sie eR ne (K) 35 -75
SOGTUI EES en tea waa (Na) 12.14 26.15

Motal’Solids (157 (5 0 voy eaeaiee sie eel eane 46.36 100.00

It will be noticed that at the low stage of water 61.57 per
cent. of the dissolved matter removed is common salt, and 8
per cent. is Epsom salt.

This dissolved matter is invisible and consequently not of a
kind to attract so much attention as the mechanical sediments,
but the total fora day, a month, ora year, is an impressive
one. The amount carried down in this form from October,
1887, to September, 1888, was 6,828,350 tons, and averaged
569,029 tons per month; during the single month of May,
1888, 1,161,160 tons were carried out in solution. When it is
remembered that this material has all been dissolved from

Erosion in the Basin of the Arkansas River 363

hard rocks within the drainage basin of the Arkansas River
some conception can be had of the importance of this method
of land degradation.*

The relation existing between the matter in solution and
that in suspension is what one would naturally expect, viz.:
when the river is high there is least dissolved and most sus-
pended matter to the gallon of water, and vice versa. This,
however, must be regarded as avery general rule to which
there are many and important exceptions. The results for
the month of April, 1888, will serve as an example of these
relations.

During that month eight sets of observations were made
with the following results :

TABLE SHOWING THE FLUCTUATING RELATIONS OF SUSPENDED TO
DISSOLVED MATTER.

ae eas ls! aa aed ada Tons per day. toe
1888. ft. per | Sus- | Dis- | In Sus- |InSolu-

sec, pended.| solved.) pension.) tion. | P&T day.
April 9. 5.75 |19,608] 29.41 | 15.41 | 26,619.1| 13,947.7| 40,666.8
So 13.65 |62,128, 85.60 | I1.00 |235,486.1| 31,546.1 | 267,032.2
SonP SIA: 16.30 |92,199, 122.50 | 13.60 |519,858.9) 59,880.3 579,739.2
16. 17.00 |98,233| 174.30 | 15.30 '793,852-0 68,176.8 862,028.8
Casita tos 13.35 |65,512| 112.60 | 15.70 |340,517.5| 47,478.9 | 387,996.4
ah Wee 3 10.70 |38,365) 58.50 | 15.00 |103,595.8) 26,563.0) 130, 158.8
coe 25 6.20 |17,627) 45.17 | 43.76 | 36,753.1| 35,605.9| 102,459.0
OTE G2oe 5-50 |16,214| 31.83 | 42.53 | 23,822.8] 31,831.1| 55,653.9

* But little attention has been given to the determination of mineral
matter removed in solution from the land. The observations of hy-
draulic engineers to whom we are indebted for the determinatiou of me-
chanical sediments, have not included the discharge of matter in solu-
tion, for the reason, no doubt, that they have had to deal practically
with the mechanical sediments only.

334 John Casper Branner

Taking the observations for the entire year under considera-
tion, the matter in solution is equal to about .31 of that in
suspension, or a little more than one-fourth of the total
amount removed. ‘These relations, however, are not constant,
as may be seen by a comparison of the totals in suspension
and solution during the individual months or on individual
days. In November, 1887, for example, the dissolved matter
was greatly in excess of the suspended matter—more than six
times as much—while on Oct. 13th, 1891, the suspended mat-
ter was more than thirteen times the matter in solution.

Attention is called to the larger percentage of silica in the
water in times of freshets ; 1.83 of the total at low water, and
11.81 of the total at high water.* The water at low gage read-
ings is all spring water, or water that has passed through the
rocks or soils instead of over them, while that at high readings
is chiefly surface water. It seems probable, therefore, that the
silica exposed over the surface of the ground is rendered more
soluble by its exposure to weathering influences and to the
organic acids of decaying organic matter, than is that of the
unexposed rocks through and over which underground waters
pass.

The Results.—The following tables are based upon gage
readings for every day of the year, a complete set of velocity
and discharge observations made and comprehensive samples
of water collected on 32 days. From these observations inter-
polations were made to complete the table. The results of
two independent sets of interpolations agree closely.

*TInasmuch as only one pair of analyses was made to determine this
point it is possible that a generalization on this subject is not to be
trusted, in any case it is desirable that other observations be made on
this subject.

Erosion in the Basin of the Arkansas River

DURING THE YEAR 1887-8.

335

MATERIAL CARRIED BY THE ARKANSAS RIVER PAST LITTLE ROCK

Tons in Tons in Tons in Suspen-
1887. Suspnesion. Solution. ston and Solution,
October, 377,557-2 354,171.9 731,729.1
November, 16,449.9 102,082.4 118,532.3
December, 700, 558.2 444,062.5 I,144,620.7
1888.
Jantwary,) <2. -. 230, 400.4 481,925.9 712,326.3
February,.. . 999,398.0 468, 320.5 1,467,718.5
March, . 2,391, 281.0 666,753.5 3,058,034.5
April, 4, 381,629.2 818,474.6 5,200, 103.8
My, Pee 6,208,717.0 I, 161,160.0 7,369,877.0
June, 4,467,377.4 860, 214.0 5:327,591.4
AOU eerie creas ee 296, 234.2 499, 869.2 796, 103.4
August, . 121,955.5 383, 369.5 505, 324.0
September, . . 1,280,020.6 577,946.4 1,857,967.0
21,471,578. 6,828, 350. 28,299,929.

The total bulk of this material would make a cube whose
sides would be 749.2 feet in length.* ‘The total suspended

* The specific gravity of the suspended matter is assumed to be 2.13—
an assumption based upon an average of seven determinations of the
specific gravity of Arkansas River sediments. It is worthy of note that
six of the samples used in these determinations were taken from sedi-
ments deposited naturally along the river, and one of them was taken
from the water used in making the laboratory determinations on sedi-
ments. The specific gravity here used is therefore somewhat too high.

DETERMINATIONS OF SPECIFIC GRAVITY OF ARKANSAS RIVER SEDI-
MENTS.

No. 1.—Sp. gr. 1.7921. Collected Nov. 13, 1888, about 4o feet east of
the St. Louis, Iron Mountain, and Southern Railway bridge (upper
bridge) on the north bank of the river within a few feet of the water’s
edge.

No. 2.—Sp. gr. 1.7764. Collected Nov. 13, 1888, about 100 feet east
of the St. Louis, Iron Mountain, and Southern Railway bridge on the
north bank of the river.

No. 3.—Sp. gr. 1.8043. Collected Nov. 13, 1888, about 4o feet west of
the St. Louis, Iron Mountain, and Southern Railway bridge, on the
north bank of the river.

No. 4.—Sp. gr. 1.8014. Collected Nov. 13, 1888, about 100 feet west

336 John Casper Branner

matter, if spread over the hydrographic basin of the Arkansas
River above Little Rock*—140,000 square miles—would have
a thickness of .000,082 of a foot; the total dissolved matter
would have a thickness of .000,024 of a foot, or the total sus-
pended and dissolved matter would be .oco,106 of a foot in
thickness. Erosion over this area during the year 1887-8
therefore took place at the rate of one foot in 9433 years.

The interpolations made in the observations on sediments
discharged, necessarily detract from the value of the con-
clusions reached in regard to the quantity of material car-
ried out of the basin. These conclusions must, therefore,
be accepted only with the confidence to which the methods
followed in the work entitle them. The means at the com-
mand of the Geological Survey did not permit the exhaustive
observations that were desirable ; indeed, that a thoroughly
satisfactory set of observations should be made with the
modest appropriation of a state Geological Survey is quite out
of the question. The observations have some value, however,
on account of their never having been made at this pointf be-

of the St. Louis, Iron Mountain, and Southern Railway bridge on the
north bank of the river.

No. 5.—Sp. gr. 1.8090. Collected at the foot of Spring St. on the
south bank of the river. A cube of 21.9 grams was dried at 120° C., and
allowed to stand several days in the air.

No. 6.—Sp. gr. 1.17603. Collected Nov. 13, 1888, about 15 feet east of
the St. Louis, Iron Mountain and Southern Railway bridge on the
south bank of the river.

Nos. I, 2, 3, 4, and 6 were air-dried.

No. 7.--Sp. gr. 2.5632. A mixture of the sediment from six bottles
of water collected for sediment determinations, May 2, 1888.

The specific gravity of the dissolved matter is assigned it from the
specific gravities of the constituents (in their proper proportions) found
by analyzing the filtered water.

* The area of the hydrographic basin above Little Rock was kindly
furnished by Henry Gannett of the U. S. Geological Survey. Other
estimates make it somewhat larger.

} The investigations of Humphreys and Abbot include a series of dis-
charge and current measurements on the Arkansas River at Napoleon.
As those authors point out, however, (Physics and Hydraulics of the
Miss. River, 1876, p. 33) the water of White River was included in their

Erosion in the Basin of the Arkansas River 387

fore, and it is hoped that no other apology is necessary for their
publication. But whether the work had been thoroughly
comprehensive or not, it is evident from the behavior of this
large stream, fed from such a large and geologically diversified
hydrographic basin, that slight and even local changes of
meteorologic conditions may greatly change the results ob-
tained, or those that would have been obtained, had the ob-
servations been made daily instead of occasionally. The total
here given for the year 1887-8 may be twice as large or but
half as large as that for the next succeeding year even with the
same or nearly the same discharge of water. For this reason no
estimate of results fora longer period based upon these ob-
servations or estimate for any other period of time can be more
than approximately correct, because the relations of the
amount of matter carried either in solution or suspension to
the volume of water are not constant. A perfectly satisfactory
measure of the actual work done by such a stream can only
be determined by a series of observations covering a number
of years, and made in connection with careful meteorologic
observations during the same period over the entire hydro-
graphic basin. It is also evident that deductions derived
from observations upon the Arkansas River are not applicable
to the study of other streams except in a very general way.

measurements, although that stream can scarcely be regarded as a trib-
utary of the Arkansas. Their results must have been considerably
modified by the presence of so large a body of comparatively clear
water.

PALO ALTO, CALIFORNIA,
AUG., 1893.

r

te
otf

Lj

a

i

oe
af
7

an

THE CHARACTER OF THE FLAGELLA ON THE BA-
CILLUS CHOLER& SUIS (SALMON AND SMITH),
BACILLUS COLI COMMUNIS (ESCHERICH), AND
THE BACILLUS TYPHI ABDOMINALIS (EBERTH).

By VERANUS ALVA MOORE.

Recent study of the morphology of bacteria has demon-
strated the fact which Ehrenberg had foretold, that the motile
forms are possessed of flagella. The further prophecy that in
these minute hair-like appendages would be found vested the
power of locomotion, was partially fulfilled as early as 1875
by Dallinger and Drysdale, who saw these filaments con-
stantly lashing on a living, moving germ (Bacterium termo).
More recently Straus has made similar observations on several
species of bacteria. Cohn, in 1872, and Koch, in 1877,
stained the flagella on a few of the larger saprophytic bacte-
ria, but the methods which they employed were so defective
that for more than a decade no further knowledge was gained
concerning the character or existence of these minute fila-
ments. The recent development of staining methods by
which the flagella can be demonstrated on all the motile
bacteria, is therefore of considerable importance, in opening
before us a hitherto unexplored field in the study of the mor-
phology of an exceedingly large and prominent class of the
Schizomycetes.

Although considerable attention has been given to the
character of the flagella, the greater part of the work which
has been done on this subject has been directed to the devel-
opment of methods for their demonstration rather than to the
filaments themselves. Asa natural result of this, our present
knowledge of the flagella is exceedingly fragmentary, and the
few statements concerning them are, in some instances, espe-
cially with the typhoid and coli bacteria, contradictory. The

340 Veranus Alva Moore

intimate relation that exists between methods and results in
the study of the morphology of bacteria will undoubtedly ex-
plain many of these discrepancies. In the endeavor to bring
out more fully the character of the flagella of the three species
of bacteria in question, it is desirable, on account of their inti-
mate association with the development of our knowledge of
flagella, to consider first, in a general manner, the methods
that have been proposed for their demonstration and to give a
brief résumé of our knowledge of these filaments and their
accepted significance. I furthermore wish to acknowledge
my indebtedness to the various writers on this subject for
many valuable suggestions.

A SUMMARY OF OUR RECORDED KNOWLEDGE OF THE FLAGELLA OF
MOTILE BACTERIA. (I) METHODS FOR THEIR DEMONSTRATION.
(2) THEIR CHARACTER AND SIGNIFICANCE.

Cohn’ and Koch’ appear to be the first who stained the
flagella. The methods by which they demonstrated the ex-
istence of these filaments have not been successfully applied
to the smaller and especially the parasitic organisms. Al-
though our instruments and methods have been much im-
proved since Dallinger? and Drysdale made their observa-
tions, the detection of the flagella on living, moving bacteria
is a result which has rarely if ever been attained with the
small and pathogenic bacteria. From 1877 to 1889 no
further knowledge of these filaments appears to have been
acquired.

In 1889 Loeffler’ succeeded in formulating a method by
which he could stain the flagella on a considerable number of ~
bacteria. The process, however, was not satisfactory, and a
year later he published a second method’ which has since
borne his name, and which he believed would, if properly
carried out, be applicable in staining the flagella on all the
motile bacteria.

A few other methods* have been proposed, but Loeffler’s

*In au article’ published in the American Monthly Microscopical
Journal, (January, 1891), I reviewed the various methods that had been
used in demonstrating the flagella on motile bacteria up to that time.
See Literature, No. 5, 7, 10, and 11, at the close of this article.

The Character of the Flagella 341

has appeared to be the most trustworthy, although its appli-
cation to the different species of bacteria has been attended
with much difficulty. It has frequently happened, even
when the method was apparently strictly adhered to, that the
outcome has been absolutely negative, while in other in-
stances the result would be entirely satisfactory.

Since the description of the original methods the literature
on this subject has been exceedingly meager. In a commu-
nication to the American Society of Microscopists”, in 1891, I
pointed out several of the difficulties usually experienced in
the application of Loeffler’s method, and suggested certain
modifications, more especially in the technique, which I had
found would to a great extent overcome these objections. In
the same paper it was also stated that the principle laid down
by Loeffler “‘that an acid* producing germ required an alka-
line mordant, and an alkali producing organism an acid mor-
dant,’’ need not be taken in a strict sense, as the flagella on
certain of the acid and of the alkali producing bacteria could
be stained by the use of either a neutral, acid, or alkaline
mordant.

Straus” has recently reported a very simple methody by
which he could stain the flagella on certain living bacteria.
The process has given in my hands universally negative
results.

Luksch” has modified Loeffler’s method principally by

*Tn 1890, Dr. Theobald Smith (Ceztralblatt f. Bakteriologie u. Para-
sttenkunde VIII, (1890), p. 389) pointed out the fact that liquid cultures
of certain bacteria would be acid or alkaline, according as glucose or
other sugars were present or absent. These undergo fermentation with
the formation of acids. In liquids free from sugars the reaction re-
mains alkaline. (See his paper in this volume.) Petruschky’s (Ibid,
VI, 1889) classification of bacteria as acid or alkaline producing is
thus shown to depend largely on the presence or absence of carbo-
hydrates in the culture medium.

{The method is as follows: To a hanging drop preparation of the
culture a drop of staining fluid consisting of carbol fuschin one part,
and distilled water three parts, is added and the preparation examined
atonce. He states that the moving flagella can be observed for about
I5 minutes.

342 Veranus Alva Moore

using a stronger solution of tannic acid in the preparation of
the mordant and by the use of acetic instead of sulphuric acid
in acidifying it. A very few other minor modifications of
Loeffler’s and other processes have been suggested, but they
have in no way brought out results which entitle them to a
consideration. Brown’s” method is practically a modification
of Trenkmann’s process.

During the brief period of time that the existence of flagella
on the smaller and especially the pathogenic bacteria has
been known, two valuable applications of this knowledge have
been made :

(1) Their use as a basis for a general classification of the
Schizomycetes. Soon after the appearance of Loeffler’s first
method (1889) Messea*, an Italian investigator, proposed a
new systematic classification®* of bacteria based upon the num-
ber and arrangement of the flagella. His classification is as
follows :

I. GYMNOBACTERIA (non-motile).

II. TRICHOBACTERIA (mo/ile).

1. Monotricha. 3. Amphitricha.
2. Lophotricha. 4. Peritricha.

The Monotricha have one flagellum at one pole of the bacil-
lus (Bacillus pyocyaneus). ‘The Lophotricha have a tuft or
bunch of flagella at one pole of the bacillus (Bacéllus of blue
milk). ‘The Amphitricha have a flagellum at each pole
(Spirillum volutans). ‘The Peritricha are provided with rows
of flagella (Bacillus typhosus).

* Kruse (Centralblatt f. Bakteriologie u. Parasitenkunde, IX, (1891),
p- 107) in reviewing Messea’s classification, considers it of only second-
ary importance. His reason for this is, that it is unnatural in that it
places bacilli, spirilla, and a micrococcus together in one group (the
Monotrichia). It does not seem necessary to consider a pioneer classi-
fication secondary merely because of an apparent inconsistency, espe-
cially in a subject about which so little is known. Undoubtedly
Messea’s classification was based on too limited a number of examina-
tions, and more extended investigations will probably cause many
changes to be made. At present, however, it is the only classification
which incorporates the complete morphology, as known at the present
time, of motile bacteria.

The Character of the Flagella 343

(2) Their assistance in differentiating closely allied species.
Luksch” in differentiating Bacillus typhi abdominalis and
Bacillus coli communis made use of their flagella. He
found from one to three flagella on the colon bacteria, but the
typhoid bacilli were endowed with from 8 to 12 filaments, a
difference sufficiently great to be of differential value. He
experienced much more difficulty in staining the flagella on
the colon germ than on any of the other motile bacteria.

Tavel® has recently made the statement that Aacillus
coli communis has no flagella* but that the typhoid bacillus is
provided with.them. This statement is qualified by a preced-
ing one, that Bacillus coli communis is a non-motile organ-
ism, which would indicate that he was working with a differ-
ent species.

In the articles, already mentioned, on the demonstration of
the flagella a brief description is given of the motile append-
ages on the typhoid and a few other bacteria. Dallinger* and
Zettnow™ have discussed the flagella on a few species, more
especially the saprophytic spirilla. In addition to these, there
are brief mentions of the filaments on the typhoid and other
species of bacteria scattered throughout the literature of the
past three years, but so faras I am aware, they are too incom-
plete to be considered of any specific value.

THE COMPARATIVE DIFFERENTIAL VALUE OF THE FLAGELLA AND
THE BIOLOGICAL PROPERTIES OF THE BACILLUS CHOLERA SUIS,
B. COLI COMMUNIS, AND B. TYPHI ABDOMINALIS.

Bacteriology recognizes more fully, perhaps, than any other
branch of biological science, functional properties in the forma-
tion of species and varieties. There are writers on this sub-
ject who consider every variation in the characters or proper-
ties of bacteria of specific or varietal significance, while there
are others who hold more rigidly to the morphology of these
organisms in determining their specific differences. The
question, therefore, are specific differences in bacteria deter-
mined by their morphological characters or by their biological

*In 1891 I published a brief description of the flagella on the colon.
bacteria (Proceedings of the Am. Soc. of Microscopists, 1891).

344 Veranus Alva Moore

(including etiological) properties, is one which, as yet, has no
clearly defined and uniformly accepted answer. Messea’s
classification of motile bacteria is based on morphological
characters only, and it recognizes genera, but not species.
Luksch goes still further and points out a specific difference
in the number of flagella of the typhoid and colon bacilli, two
well recognized species of one genus. On the other hand, the
more extended investigations of the biological properties of
bacteria are continually bringing forth new facts, and reveal-
ing variations in the properties of these organisms which are
not explained by corresponding differences in their morpholo-
gy. There are bacteria which possess marked difference in
their biological manifestations which resemble each other so
closely in their structure that, with our present knowledge,
their differentiation by purely morphological characters, is
practically impossible. In the group of bacteria which
includes Bacillus cholere suis, Bacillus coli communis, and
Bacillus typhi abdominalis we have an excellent illustration
of this fact. These species resemble each other very closely
morphologically but they are readily differentiated by means
of their biological and etiological properties. In this group,
therefore, is found a most rigid test for the differential value
of the flagella.

It may be assserted that these bacteria do not belong to the
same group, and while in a narrow sense (considering their
more characteristic physiological manifestations only) it may
be true, yet morphologically they are small, motile bacteria
belonging to the Peritricha (Messea) and, in certain other re-
spects, they are closely enough related to one another to be
enrolled in the same genus, while their physiological and eti-
ological properties mark their specific differences. In order
that the differential importance of the biological and etiolog-
ical properties of these bacteria may not be overlooked in the
subsequent consideration of the specific character of their
flagella, a brief summary of the more important of these prop-
erties for each of the germs in question, is appended :

(a). Bacillus cholere suis is a small actively motile germ which
is found in the organs of swine suffering from hog cholera. It

The Character of the Flagella 345

has not been found outside of the diseased animal body (or its immedi-
ate surroundings). It is fafa/to experimental animals when injected
beneath the skin in small numbers. In larger doses it will produce the
disease in swine. Jt ferments glucose with the formation of gas. It
does not coagulate the casein in milk.

(6). Bacillus typhi abdominalis is slightly larger than the bacil-
lus of hog cholera and not so uniformly actively motile. It is found
in the intestines and organs of people suffering from typhoid fever and
is generally accepted to be its cause. Like the hog cholera bacillus, its
natural habitat outside of the diseased body is not known. It is mot_fa-
tal to experimental animals when they are inoculated with moderate
doses. Jt does not ferment glucose with the formation of gas*. It does
not coagulate the casein in milk.

(c). The Bacillus coli communis is a very feeble or more actively
motile bacillus varying somewhat in size but usually about as large as
the typhoid bacillus. It is found in the healthy intestines of both man
and the lower animals. It does not appear to live in nature outside of
the animal body. It is /ata/ to rabbits when they are inoculated with
large doses of the pure culture. J¢ ferments glucose with the forma-
tion of gas and coagulates the casein in milk.

Another very important feature in the study of the relation,
from a differential standpoint, that exists between the bio-
logical properties and the character of the flagella of these
bacteria, is the fact, which is verified by many observations,
that these organisms exist in nature (z. é., the coli in the
healthy intestines, and the hog cholera and typhoid bacteria in
the organs of the victims of their respective diseases), in vari-
ously modified forms in which the differences (biological and
pathogenic) which separate the more typical species are very
much diminished. This variation, especially in the patho-
genic properties of the typhoid and colon bacteria, has given
rise to a theory, advanced by Rodet and Rofix™, that the
typhoid germ is a modified form of the colon bacillus. In
the investigation of animal diseases, hog cholera and colon
bacteria have been found which varied in size and in their bi-
ological and pathogenic properties to a marked degree from

* The fact that the typho‘d bacillus would not ferment glucose with the formation
of gas, was first pointed out by Dr. Theobald Smith in 1890. (Centralblatt f. Bakterto-
logie u. Parasitenkunde VII, 1890. p. 502).

346 Veranus Alva Moore

the more typical forms of these species.* This would indi-
cate that the evolutionary theory of Rodet and Rotx is as
applicable to the hog cholera germ as it is to the typhoid
bacillus. Although the deyelopment of these specific patho-
genic bacteria from a common intestinal germ is improbable,
yet the possibility can not be gainsaid and the importance
which this theory has in its bearing upon public health, as
well as in its relation to pure bacteriology, renders its demon-
stration of much interest. This, and many other interesting
problems connected with the specific limitations of these bac-
teria, emphasize the importance of determining as far as
possible the extent to which their flagella may be deemed of
differential value. In my efforts to do this, I have considered
the flagella not only of the more typical species but also of a
considerable number of modified forms (excepting the typhoid
bacillus) of these bacteria. From these investigations, I have
found their flagella to be much more constant than ‘their bio-
logical properties, but contrary to Luksch, I have not found
them to be of specific differential importance. The evidence
to support this conclusion is found in the subsequent descrip-
tion of the character of the flagella.

I have limited myself to a consideration of a very few of the
many interesting questions which have presented themselves
in the study of the flagella of these bacteria. A large amount
of experimental work was necessary before a satisfactory
method for their demonstration could be formulated. This
being accomplished the specific objects which I endeavored
to attain are:

1. To complete as far as possible our knowledge of the mor-
phology of each of these organisms.

*In a communication to the Biological section of the American
Association for the advancement of Science, in 1890 (New York Med.
Journal LAI (1890) p. 485). Dr. Theobald Smith described a hog cholera
bacillus which was, ‘‘in every way nearer the saprophytic forms (coli)
than the germ usually found in epizootics of that disease.’’ I have
found similar variations in the colon bacteria isolated from variously
diseased organs of different animals. In an outbreak of swine disease
in 1892, I isolated several colon bacteria which approached in their bio-
logical characters very closely to the hog cholera organism.

The Character of the Flagella 347

2. To determine whether or not there is a difference in the
number or character of the flagella of the modified forms of
these bacteria corresponding with the variations that are found
to exist in their physiological and etiological manifestations.

3. To determine the significance of the flagella in classifying
motile bacteria, as illustrated by a comparative study of these
filaments on three typical species, representing morphol-
ogically three closely allied groups*, and biologically three
distinct groups, of bacteria.

It was my opinion in 1891 that there was a well marked
specific difference in the flagella of these species, but more ex-
tended investigations have caused me to recede somewhat from
that opinion and to call attention at this time, in accordance
with the results of my observations, to the similarity which
exists between them.

METHOD FOR STAINING THE FLAGELLA.

The difficulties which have been experienced in the demon-
stration of the flagella both by myself and others, necessitate
a somewhat careful consideration of the method which has
been followed in obtaining the results herein recorded. As I
have been unable to detect the flagella on living bacteria, my
descriptions apply tostained preparations only. With the ex-
ception of certain modifications, Loeffler’s method has been
followed. ‘The advantages that are claimed for the modified
method over the original process are : (1) the preparations are
more uniformly free from a deeply stained backgrotind which
conceals entirely or renders indistinct the individual filaments ;
(2) there is a better distribution of bacteria on the cover-glass ;
(3) the application is more simple and the results more trust-
worthy. The majority of the changes which I have made
were fully described in a previous article’. The others are
incorporated here. The method as I have used it, is as follows :
the principle that is involved in staining the flagella is
simply the one employed in the use of a mordant or fixative.
The methods which have been at all successful (beyond the
experience of the originator) in staining the flagella require a

* Group is here taken in a narrow sense, signifying a species and its
varieties only.

348 Veranus Alva Moore

mordant which contains tannic acid. The other elements
have varied. The technique of the method therefore consists
in treating the cover: glass preparations of the bacteria with a
mordant prior to, or together* with, the application of the
staining fluid.

The mordant :t

Wieo mer cent. Solution of ‘tammieiaerds csr cies delete LOCC;
A cold saturated solution of sulphate of iron .......... 5 ee
A saturated alcoholic solution of fuchsin........... Joi bees

If possible chemically pure tannic acid should be used.
This mordant can be used in staining the flagella of these
three species of bacteria, but slightly better results appear to
be obtained with the typhoid and colon bacteria when a few
drops of a 10 per cent. solution of sulphuric or acetic acid are
added. With the hog cholera bacteria a mordant containing
a 10 per cent. solution of tannic acid gave equally good results.

The staining fluid:{ For this I have used carbol fuchsin
prepared after Ziehl’s formula.

*JT have found, since the greater part of the work on this article was
completed, that certain staining fluids (alcoholic: solutions) could be
mixed with the mordant thus eliminating their subsequent application. I
have not perfected the formula for this combination but have obtained
excellent results with a fluid composed of a 20 per cent. solution of
tannic acid 2 cc., saturated solution of sulphate of iron 1 cc., and a sat-
urated alcoholic solution of fuchsin 1 cc., filter and apply in the same
manner as the mordant, but for a much longer time.

+ This is Loeffler’s standard or neutral mordant. It is successfully
employed in staining the flagella on many motile bacteria. The
addition of a few drops of a Io per cent. solution of sulphuric acid ora
similar quantity of a I per cent. solution of sodium hydrate appears to
give better results, if indeed it is not absolutely necessary, with certain
other species. My personal experience tends to prove that no sharp
and fixed lines can be determined for the preparation of a universal
mordaut. I have been unable, however, to stain a single flagellum by
the use of amordant not containing tannic acid, although I have tried
nearly all of the known ‘‘fixatives.’’ As I have stated elsewhere’ a
weaker solution of tannic acid can sometimes be used with advantage.

tI have stained the flagella with nearly all of the basic aniline dyes
ordinarily used in bacteriological work. The carbol fuchsin gives a
deeper stain and consequently a clearer definition of the filaments is
obtained.

The Character of the Flagella 349

RECITES AG: 2 CULT ek els hart Sanat Cece RU ah Roepe lys!l'tard.é-a) , BAT.
Pestle ALCOHOL, | ets a al 12d tein teas dectineeie) 244.9) LOCCC.
A 5 per cent. solution of carbolic acid. . . . . . . 100 Ce.

The fuchsin is dissolved in the alcohol, after which the acid
solution is added.

The cover-glass preparations: ‘The cover-glasses must be
perfectly clean. The desired number of cover-glasses are
then arranged on a level tray. A large drop of warm water
(distilled or hydrant) is placed upon each cover-glass by
means of a sterile pipette. If the cover-glass is properly
cleaned * the drop of water will spread over its entire surface.
The point of a cooled, flamed platinum wire is very gently
touched to the surface growth of the germ on agar or gelatine
and carefully immersed in the water near the center of the
cover-glass. A sufficient number of bacteria will adhere to
the wire to make from six to ten preparations. ‘The tray with
the cover-glasses is then placed in an incubator at a tempera-
ture of about 36°C. until the water is evaporated. Many of
the bacteria on account of their power of locomotion, and by
means of the currents produced in the liquid during its evap-
oration, will be fonnd, in the dried preparations, to be isolated
from the clumps of bacteria that were introduced with the
wire and distributed very evenly over a large vortion of the
surface of the cover-glass. This natural distribution prevents,
toa marked extent, the breaking off of the flagella which
occurs when the distribution is made by mechanical means
in asmaller quantity of the diluent. If the water to be used

* Weber (Fortschritte der Medicin Bd, XI. (1893), p. 49) has found
that when the percentage of calcium is too small in proportion to the
alkalies (sodium and potassium) in the composition of the glass, the
atmosphere will produce a chemical change in the glass which gives its
surface a peculiar moist condition. This may explain to some extent
the cause of the deeply stained background where the proper precau-
tions were taken to prepare the cover-glasses. I have frequently no-
ticed that in the use of cover-glasses that had been cleaned and ex-
posed to the atmosphere for a considerable time prior to their use, the
water would “‘ roll up”’ in drops, as though the surface was covered with
a film of oil, and when stained they would invariably exhibit a deeply
stained background.

350 Veranus Alva Moore

on the cover-glasses is heated: to a temperature of about
40-45° C. and the preparations placed at once in the incubator,
the bacteria are more evenly distributed.

After the preparations have dried the bacteria are fixed to
the cover-glass by heat. ‘This can be accomplished either by
passing them, film upward, ¢w7ce through the flame of a spirit
lamp or Bunsen burner, or by heating them from 120°-140° C.
for from five to ten minutes in a hot air chamber. ‘The latter
is to be recommended when facilities will permit.

The application of the mordant and staining fluid: In ap-
plying the mordant the preparations are completely im-
mersed in the fluid. In place of a watch glass as formerly
recommended, I have used a large (one inch) test tube for
this purpose. From three to four c. c. of the mordant is placed
in the tube into which the cooled, heated cover-glass prepara-
tion is dropped. ‘The tube is held over a flame until steam is
given off when it is removed. The mordant should be fre-
quently agitated by gently shaking the tube. After from five
to ten minutes the cover-glass is removed by the use of a wire
hook on the end of a glass rod and with a pair of fine forceps.
The cover is thoroughly rinsed in clean water, or better, in a
stream from a spigot or wash bottle. If there is a grayish
film on the preparation it can usually be removed by rinsing it
in strong alcohol and again in water.

The staining fluid is applied ina test tube in precisely the
same manner as the mordant. It is allowed to act for from
one to three minutes.

The mordant should be fresh and always //tered before it is
used. The carbol fuchsin can be kept in stock solution for a
considerable time. The success of the operation depends
very largely upon the cave with which itis performed. ‘The
method as described gives excellent results with the three
species of bacteria under consideration, and it has been suc-
cessfully applied to a few others.*

*In the application of the method to other bacteria whose flagella
will not stain by the use of a neutral solution, trials must be made with
acid and alkaline mordants, and possibly with mordants containing
different quantities of tannic acid, until a successful combination is
found.

The Character of the Flagella 351

Cultures used; In this work, agar cultures have been em-
ployed. Unfortunately the staining method is not so appli-
cable to preparations of bacteria from bouillon cultures on
account of the presence of organic substances in the bouillon,
which form a deeply stained back ground. I have, however,
succeeded in making a few quite satisfactory preparations from
these cultures. Gelatin and potato can be used, but with our
present methods the surface of inclined agar appears to be the
most satisfactory sub-stratum upon which to grow the bacteria
for this purpose.

A DESCRIPTION OF THE COMMON AND MORE SPECIFIC CHARACTERS OF
THE FLAGELLA ON THE BACILLUS CHOLER& SUIS, B. COLI COMMUNIS,
AND B. TYPHI ABDOMINALIS.

In stained preparations for the exhibition of the flagella on
these bacteria, there are so many variations and exceptions to
what might be termed a typical presentation of the body of
the germ and its motile appendages, that at present, a formula
for their description can not well be written. In order to
avoid repetition I shall first describe in a general way, such
characters of the flagella as are common to the three species.*

The staining process necessary to bring out the flagella
increases to a slight extent the size of the body of the germs.
This is probably due either to the staining of a ‘‘ capsular ’’
substance which may surround the bacteria, and which is not
brought out by the ordinary staining methods, or to the swell-
ing of the cellular substance on account of the action of the
mordant.t

*In this discussion the well-known morphological characters (size
and form) of these bacteria are omitted. The rod-shaped forms will be
spoken of as the body of the germ wherever it is necessary to distin-
guish between it and the flagella. The terms motile appendages, and
filaments are used synonymously with flagella.

} Zettnow" holds with Klebs and Biitschli, that the part of the germ
which is easily brought out by the ordinary staining methods is the
nucleus only, and that the additional part which is demonstrated by the
use of Loeffler’s method is a plasma which surrounds the nucleus.
Wahrlich (Article reviewed in Centralblatt f. Bakteriologie u. Par-
asitenkunde XI, (1892) p. 49) found two substances in bacteria cells, (1)
the basis, a substance which gave the micro-chemical reaction of linen,
and (2) a chromatine substance or nucleus which is contained within
the meshes of the basis.

352 Veranus Alva Moore

In the microscopical examination of well-executed prepara-
tions for exhibiting the flagella three conditions have been
universally observed: (1) In certain fields there were a
greater or less number of bacteria which exhibited no flagella;
(2) there were a considerable number of detatched or free fla-
gella lying between the bacteria; and (3) the numbers of fla-
gella on the different bacilli were not constant. On the other
hand, however, fields could be selected in which there were no
detatched filaments and where every germ was provided with
motile appendages.

The flagella appear as hair-like appendages or filaments,
which radiate from the bacteria. They are given off from the
cell wall of the germs of which they appear to be continua-
tions or projections. ‘This can be clearly shown by their re-
action to the following staining fluid. If to 3c. c. of the mor-
dant 1c. ¢. of a saturated alcoholic solution of fuchsin is added
and the preparation treated in the usual way with this solu-
tion for about five minutes, the flagella and periphery of the
bacteria will be stained with equal intensity, while the central
portion of the cells will remain unstained. By allowing the
reagent to act for a much longer time or by applying the usu-
al stain, the entire organism will become deeply tinted. This
would indicate that the cell wall and flagella were alike in
their composition, or at least in their reaction to a certain
staining fluid, and that the contents or nucleus was different.
The sharp outlines of the flagella as observed in stained prepa-
rations, would indicate that they are organized elements. I
have been unable to make out any differentiation of their
structure.

The appearance of shorter and longer free flagella and the dif-
ference in the length of those still attached to the body of the
germs is due apparently to their detachment and breaking dur-
ing the separation of the individual bacteria from the closely
packed masses in which they grow on solid media. In these
cultures the long filaments on the different individuals ap-
pear to become entangled with each other, causing the
separation of the bacteria to be accomplished with difficulty
and presumably with more or less injury to their organs of

The Character of the Flagella 353

locomotion. This is suggested by watching the clumps of
bacteria in a hanging-drop preparation. ‘The germs at the
edge of these masses, when about to separate themselves from
the others, exhibit first a trembling motion, then a jerking,
reeling and pitching movement, until finally they are free *
and move across the field.

Furthermore, in the examination of a hanging drop prepa-
ration made froma bouillon culture the bacteria are observed
to move much closer to each other than the length of their
flagella, and it seems highly probable that detachment or
breaking of the appendages is produced during these volun-
tary movements, by their contact and possible entanglement
with each other. Free flagella have been found to be numer-
ous in stained preparations made from liquid cultures. For
the ultimate settlement of these questions a method must be
devised by which the motile appendages can be observed on
the living and moving germs. At present we are forced to be
content with the study of the appearances that are presented
in stained specimens, presuming that as the conditions of
preparation are the same the characters that are revealed will
be correspondingly similar in the different species.

The length of the flagella as seen in stained preparations
varies to a marked degree. ‘The longest I have measured was
18 » or about nine times the length of the body of the
bacillus (hog cholera).

The diameter of the flagella varies in different preparations
and frequently in the same specimens, to a marked degree.
In a deeply stained preparation they are occasionally 0.4 p
in diameter, or about one-third of the diameter of the body of
the germ. More commonly they are about o.2 » in diameter,
or about one-sixth the thickness of the organism. Again they
may appear as extremely delicate lines, so fine that it is with
difficulty that they can be seen at all. Usually, however,
they are about 0.2 » in diameter. The unexpected appear-
ance of these variations has thus far baffled an explanation,

*It is an observable fact that the character of the movement of the
individual germs is somewhat varied. This may be due to the loss of
certain of their motile appendages.

354 Veranus Alva Moore

although many series of preparations have been carefully
made to discover the cause. I believe, however, that the fail-
ure is due to the technique rather than to a variation in the
filaments. The diameter of the flagella is appreciably the
same at the distal end as at the union with the body of the
germ. Occasionally, however, the distal portion appears to
be very slightly tapering.

Among the free flagella is sometimes observed what appears
to be a strand or bunch of twisted filaments, varying from one
to two p in width, which presents a uniformly, deeply stained
appearance. At one or both ends the filaments are separated
from each other, giving the appearance of the frayed end of a
cord. In preparations from old cultures several flagella which
radiate from the same point are frequently observed. They
present the appearance of the filaments of a single germ.
These are occasionally observed in preparations from young
cultures.

Frequently a flagellum will present throughout the greater
part of its length a very close, wavy condition. There are in
addition to these many other anomalous appearances which
have as yet no clearly defined significance.

In the study and comparison of the flagella, I have em-
ployed cultures varying in age from sixteen hours to three
days. ‘There appeared to be no difference in the character of
the flagella on the bacteria in cultures of these ages, but in
preparations made from those of a longer growth there was
usually a much larger number of broken and detached fila-
ments.

The exact arrangement of the flagella on the body of the
germ is hard to determine. In stained preparations the or-
ganisms are dried to the cover-glass with the filaments in such
positions that they seem to radiate from the outer edges of the
germs as they appear in the stained specimen. Frequently
they all appear to come from a very small arc on the circum-
ference. ‘This is undoubtedly due to our inability to detect
the filaments as they cross the body of the germ. ‘The fla-
gella are given off from both extremities, and at variable
points along the intervening portion of the body of the germ,

The Character of the Flagella 355

although a single bacillus which exhibits this uniform radia-
tion of motile appendages is rarely observed in stained prepa-
rations. ‘The flagella are usually more or less wavy, and it is
the rule, though it has many exceptions, that the waves in a
single flagellum are uniform.

I have studied very carefully the flagella on several hog
cholera bacteria. These were obtained from different sources
(outbreaks of hog cholera) and a few of them exhibited slight
variations in their biological characters and more marked dif-
ference in their virulence. So great have been these varia-
tions in a few cases that the bacteria have been deemed modi-
fied forms. I have also studied a larger number (about 20) of
colon bacteria isolated from variously diseased organs of differ-
ent animals and from the human intestine. These have also
shown a marked difference in their properties. The two cul-
tures more specifically described represent (1) the more typical
form (2) a somewhat modified form. Of the typhoid bacteria,
only two cultures have been at my disposal. All of these
bacteria have been carefully studied and their identification
clearly established. In these examinations I have been un-
able to detect any constant, specific difference in the character
of the flagella on the germs from the different cultures of the
same species. On this account bacteria from only two cultures
of each species will be considered in the more specific descrip-
tion of the flagella.

The flagella on Bacillus cholere suis. (Plate 1, Fig. 1.)
(1) Aculture of hog cholera bacteria which was obtained from
a pig that died in an outbreak of hog cholera in the State of
Illinois in the fall of 1891. An examination of the bacteria in
a hanging drop preparation showed them to be universally
actively motile. ‘They were virulent.

The number of flagella on the different germs, as observed
in the stained preparations, was variable. The most usual
number was from two to five. A few germs have been found
upon which nine filaments could be counted, but it is the ex-
ception to find more thaneight. Frequently the filaments are
bent upon themselves in such a way that it is very difficult to
determine the exact number, especially when it is large. In

356 Veranus Alva Moore

a few instances I have thought it possible for as many as
twelve filaments to be present. In order to estimate the most
usual number an actual count of the flagella on a large num-
ber of germs was made. ‘These were taken from somewhat
ideal fields on a considerable number of preparations. In
these fields there were from 2 to 10 bacteria which were well
separated** from each other and on each of which all of the
flagella could be counted; that is, there were no clumps of
bacteria present. Care was always taken to avoid extreme
conditions.

Of these the number of flagella on two hundred individual
germs was as follows, 12 had no flagella, 23 had one, 30 had
two, 47 had three, 39 had four, 22 had five, 12 had six, 8 had
seven, 5 had eight and 2 had nine. In many of the fields
there were no free filaments, while in others there was a vari-
able number.

The longest flagellum that I measured was 184. The
usual length was from 7 to 12m. Shorter ones were quite
common. Occasionally the ends of the filaments were curved
into nearly or quite perfect circles or rings with a diameter of
about 1.5. These were not uniformly present but in occa-
sional preparations they were quite conspicuous.

(2) Aculture obtained from an outbreak of hog cholera in
the State of Maryland. A microscopical examination of a
hanging drop preparation showed the bacteria to be actively
motile. ‘They were less virulent than those in the previous
culture. Cover-glass preparations treated and stained as in
the preceding case revealed no appreciable difference in their
staining properties, the number, arrangement, and character

* This is very important, for the tendency of the bacteria to be
united in twos or small clumps which might easily be mistaken fora
single germ is very marked, and the flagella which belong to two germs
could be readily considered as those of a single individual. This is
especially true where the bacilli are united end to end.

{In measuring the length of the flagella the distance from the body
of the germ tothe distal end of the filament along its general course
was taken, without allowance for the minute curves or waves which
would in some instances, if considered, add an appreciable amount to
the recorded length.

The Character of the Flagella 357

of their flagella. To complete the comparison the number of
flagella on 200 germs is recorded. Of these, 10 had no
flagella, 33 had one, 33 had two, 45 had three, 38 had four, 19)
had five, 6 had six, 8 had seven, 6 had eight ; and 2 had nine.
The longest flagellum observed measured 11». The usual
(about 75 percent.) length was from 6 to 8y. The small
circles at the distal ends were also present but in small num-
bers. .

Flagella on Bacillus coli communis. (Plate 1, Fig. 2). A
culture of the bacillus coli communis, obtained by Dr. Theo-
bald Smith from the human intestine. A microscopical ex-
amination of a hanging drop preparation from an agar culture
of this species showed comparatively few of the germs to bein
motion. Upon watching it carefully for several minutes,
many of the individual germs which were first at rest ex-
hibited an active motility.

The diameter and arrangement of the flagella on this species
do not differ to any appreciable degree from those on the hog
cholera bacteria. The number of filaments on the individual
germs varied considerably. Seven was the maximum number
found on a single organism. As before, an actual count of
the flagella on 200 individual germs selected from representa-
tive fields was made. Of these, 9 exhibited no motile ap-
pendages, 33 had one, 58 had two, 44 had three, 34 had four,
15 had five, 4 had six and 3 had seven. The number of the
free flagella in many of the fields averaged about one to each
germ. ‘This is unimportant as in other parts of the prepara-
tions the number was greater and in still others less. The
length of the filaments varied from 2 to12p. ‘The greatest
number (66 per cent. of a large number measured) were from
5to7p. It is of interest to note that the number of individual
bacteria which exhibited no flagella was no larger in this
species than in the preparations of the hog cholera bacteria
where apparently every germ was actively motile. A very
few of the flagella formed nearly or quite perfect circles or
rings at their distal ends. ‘heir existence, even in small
numbers eliminates their specific value when compared with
hog cholera and typhoid bacteria.

358 Veranus Alva Moore

(2). A culture Bacillus coli communis obtained from the
pectoral muscle of a pig which died in an outbreak of swine
disease in 1892. ‘The motility of the bacteria in this culture
was less marked than in those from the previous culture.
The flagella extended out from the body of the bacteria in
delicate, more or less wavy filaments. In diameter, course,
and general appearance they differed in no perceptible manner
from the flagella on the previously described germ. The
maximum number of filaments that was found on an indi-
vidual was one less than in the previous case, and the num-
ber which possessed but one flagellum was proportionally
larger. ‘The number of detached filaments was not in excess
of those in the preparations of the colon bacteria from the
human intestine. In order to arrive at a more accurate com-
parison, the flagella on 200 individual bacteria from selected
fields were counted. Of these, 11 showed no flagella, 83 had
one, 55 had two, 29 had three, 13 had four, 6 had five, and 3
had six. The maximum length of the filaments measured
was 15p. ‘The length of the greatest number varied from 5
to 9 p.

Flagella on Bacillus typhi abdominalis.—( Plate I, Fig. 3).
For my cultures of typhoid bacilli I am indebted to Dr. Theo-
bald Smith. These cultures were from two to four years
old. Unfortunately I have no knowledge of the history
of these cultures prior to their arrival in our laboratory.
(1) A culture obtained from the Johns Hopkins Hospital,
Baltimore, Md. When examined in a fresh condition (hang-
ing drop) the majority of the bacilli were observed to be in
active motion.

The arrangement of their flagella was not perceptibly dif-
ferent from those on the hog cholera and colon bacteria. In
the examination of different preparations of this bacillus a
considerable variation was found to exist in the appearance of
its flagella. A certain number of the bacilli were provided
with long, nearly straight or wavy filaments which extended
in various directions from the body of the germs, while the
motile appendages on the greater number of the organisms
were shorter, more curved, and intertwining, presenting a

The Character of the Flagella 359

somewhat bushy appearance about the body of the germs.
In many specimens there was an exceedingly large number of
flagella which were bent at their distal ends, if attached to
the germ, into nearly or quite perfect circles or rings varying
from 1.2 to 2 « in diameter, while other filaments were curved
to such an extent that the free ends passed either above or
below the body of the germ. In many preparations I have
found fields in which one or more of the filaments on nearly
every germ exhibited these circles or rings. Their formation
is somewhat curious and their significance is as yet specula-
tive. Frequently many of the ‘‘rings’’ are broken from the
flagella. The filaments were usuallly bent at right angles to
their course at the point where the curve begins. This gave
them the appearance of the ends of certain screw hooks.
Less frequently the rings were formed by the distal part of
the filaments bending to one side, forming perfect or nearly
complete circles. In some preparations a considerable num-
ber of bacilli were observed around which were from one to
four rings or inbending filaments with few, if any, extended
flagella. The terminal rings and incurved flagella on the
typhoid bacilli were very marked, but their differential value
is destroyed by the fact that they occasionally appeared in
preparations of the other bacteria.

The detached filaments vary in number, as in the case of
the previously described organisms. ‘The number of flagella
on the individual germs also varied ; ten was the maximum
number that I was able positively to determine on a single
germ; Luksch found twelve; and according to Sternberg”,
Babes found as many as twenty on a single germ. In the
photographs of typhoid bacillus published by Fraenkel and
Pfeiffer”, and Migula”, showing their flagella, ten is the
largest number positively represented as belonging to a single
germ. In these photographs, clumps and pairs of bacilli
show a much larger number. A count of the flagella on 200
germs in well selected fields showed 9g bacilli to be without
motile appendages, 23 had one, 39 had two, 45 had three, 27
had four, 15 had five, 23 had six, 11 had seven, 3 had eight,
3 had nine, and 2 had ten. The length of the filaments

360 Veranus Alva Moore

varied considerably. The maximum length of those meas-
ured was It mw; 78 per cent. of a large number that were
measured varied in length from 3 to 6 p.

(2). A culture which was obtained from Koch’s Laboratory
(Germany). The bacteria were not quite so actively motile
as the hog cholera germs. ‘They stained readily and the fla-
gella differed in no appreciable manner from those on the bac-
teria from culture (1). There were a large number of short
flagella and rings. ‘The number of flagella on the individual
germs was estimated in the manner heretofore described.
Seventeen of the 200 germs exhibited no flagella, 43 had one,
42 had two, 45 had three, 24 had four, 18 had five, 5 had six,
3 had seven, and 3 had eight. It is possible that a few bacte-
ria had nine filaments each, but there was a doubt as to the
exactness of the count. The longest filament measured was
13 w. A large majority of those measured varied from 3 to 7
in length.

From the detailed descriptions of the flagella on these three
species of bacteria a few comparisons may be made. ‘These
can be stated best in tabulated form :

A COMPARISON OF THE NUMBER OF FLAGELLA ON THE INDIVIDUAL |

GERMS.
Average
Cul- The Number of Flagella.| Total nner oe
BACILLUS. number of
ture dctarin flagella on
011/2/3/4/5/6/7/8/9 * each germ
Cholerae suis . | (1) |12/23/30/47/39/22|T2| 8] 5] 2} 200 a4
4 oS (2) }10]33/33/45/38/19] 6| 8} 6] 2) 200 elit
Coli communis | (1) | 9/33/58/44/34/15| 4] 3 200 2.6
fs ug (2) |11/83/55/29/t3] 6) 3/(?) 200 1.8
Typhi abdomi-
nalis . . . .| (1) | 9/23/39/45|27|15/23/11| 3| 3| © 200 2.5
‘ (2) |17|43|42/45|24|18| 5) 3) 3) 3) 200 2.6

In comparing the figures in the tables the fact should
be kept clearly in mind that they have only a relative
significance. The large number of preparations examined
and the number of counts and measurements made give them,

The Character of the Flagella

361

_ A COMPARISON OF THE LENGTH, DIAMETER AND CHARACTER OF THE

FLAGELLA.
|
| |S. g Leth. off yoyal
Cul- 3 9 70 Pet Ctl diame-
BACILLUS. [ti re| bo G|or more! ter of Appearance of flagella.
ao =
BO a| of the | aacella
iI” | flagella. aad
Cholerae suis | (1) | 18 4 | 7-12 yt |O.1-0.2 /| Usually extended, wavy,
few terminal rings.
es (2); 114 | 6-8 yp |o.1-0.24 eS $s ss
Colicommunis) (1) | 12 | 5-7 sf |0.I-0.2 £6 eS ut
‘s ef |(2)| 15 # | 5-9 # |0.1-0.2Ku ae oe ‘
Typhi-abdom-
inalis . . .|(1)| 11 | 3-6 yu |o.1-0.24\|Many incurved, wavy,
| large number of ter-
minal rings.
“se (2) 13 3-7. ft |0.1-0.2 hu “c ‘o ‘c

however, a good representative value.

individual germs.

To illustrate this
point and to show how easily different results could be ob-
tained, especially in reference to the number of flagella, by
considering a smaller or possibly larger number of bacteria, I
have appended the results of the count of the flagella of 200

Here also a further difference of opinion

as to the fields to be selected might vary the final result. My
counts in this case were made from eight preparations.

o oe
Wendie Number of Flagella. : & aS3
BACILLUS oF ide BS S223
1S)
CHOLERAE SUIS. |. amined. im s WS 3
6|7|8|9|2 5
o|I ia 45 gl & as
Preparation I. 5 | 3| 628 Mpa & 32 6.4
i . 4 2) 1] 5] 7| 5| 2] 4| Tt 2 30 7-5
III. 6 I| I| 2/10 6| I] 3] 1] 3 29 4.8
IV. 3 PNW) (rail ife}| at 14 4.6
rs We 8 2| 6) 8| 6] 5) 5] 1 35 4.3
ie VI. 7 2) 3) 2 6| 4| I} I| 1 20 2.8
i VII. 3 1 5| 30 Fa owas 27 9
fs VII. 2 “i 2 2| Ea} air2ix 15 7.5
12 2313047 39 22 12 8] 5 200
| | | |

In comparing the specific characters of the flagella of the
three species, it will be observed that while there are manifest

362 Veranus Alva Moore

differences there are likewise striking resemblances. A few
of the more important facts which have been brought out in
this study to illustrate their differences and similarities are
appended.

Their difference is shown from the observation, (1) that the
length of the greater number of the flagella is greatest on the
hog cholera and least on the typhoid bacilli, while those of
the colon bacteria are of intermediate length ; (2), that the
average number of flagella on the colon bacteria is less than
that on either of the other species ; and (3), that the terminal
and free rings are much more numerous in the preparations of
the typhoid bacillus than in those of the other bacteria. This
is also true of the incurving flagella.

Their similarity is illustrated by the fact (1), that the num-
bers of flagella on the individual bacteria vary in the different
fields in the preparations from the same species as much as in
those from different species, excepting in the maximum num-
bers; this is also true of the length of the flagella ; (2), that
the diameter of the flagella on the three species is identical ;
(3), that the position of the flagella on the body of the germ
is the same; and (4), that fields could be selected in prepara~
tions from the three species in which no difference could be
detected in the character of the flagella.

CONCLUSIONS.

The foregoing examinations and the results of a careful
comparative study of the flagella of these three species of
bacteria appear to sustain the following conclusions :

1. These three species of bacteria belong to the Perttricha
(Messea).

2. There are apparently slight differences in their flagella,
but the differences are not marked enough to be deemed of
differential value. This is evidenced by the fact that the
flagella in different preparations from the same species exhibit
quite as marked variations.

3. There is no difference in the flagella of.modified forms of
the same species to correspond with the difference in their
physiological and etiological manifestations.

The Character of the Flagella 363

4. Until further facts are determined, the character of the
flagella will not furnish a means for specific differentia-
tion. ‘The species and varieties must be determined by their
physiological and pathogenic properties while the genera may
be fixed by the character of the flagella.

5. The proposition that the Bacillus typhi abdominalis is a
modified form of Bacillus coli communis caunot be justly
refuted on their morphological characters. The similarity in
the structure (as it is now understood) of these bacteria in-
creases the importance, from a differential standpoint, of the
differences found to exist in their biological and etiological
manifestations.

WASHINGTON, D. C.,
July 31, 1893.

LITERATURE.

1. Cohn, F. Untersuchungen iiber Bacterien. Bettrage zur Bio-
logie der Pflanzen, Bd. I (1872), S. 126.

2. Dallinger, W. H., and Drysdale, J.J. On the existence of fla-
gella in Bacterium termo. Zhe Monthly Microscopical Journal, (Lon-
don), vol. XIV (1875), p. 105.

3. Koch, Robert. Untersuchungen iiber Bacterien. etrage zur
Biologie der Pflanzen, Bd. II (1877), S. 416.

4. Dallinger, W. H. On the measurement of the diameter of the
flagella of Bacterium termo. Jour. of the Royal Mic. Society, vol, I,
(1878), p. 169.

5. Neuhauss, R. Ueber die Geisseln an den Bacillen der Asiati-
schen Cholera. Centralblatt f. Bakteriologie u. Parasitenkunde, Bd.
V, (1889), S. 81.

6. Loeffler, F. Ein neue Methode zum Farben der Mikroorganismen
im besonderen ihren Wimperhare und Geisseln. Centralblatt f. Bak-
teriologie u. Parasitenkunde, Bd. V1, (1889), S. 209.

7. Trenkmann, Dr. Die Farbung der Geisseln von Spirillen und
Bacillen. Jbid., Bd., (1889), S. 433.

8. Messea, A. Contribuzione allo studio delle ciglia dei batterii e pro-
posta di una classificazione. Rivista digiene e sanita publica, No. 14,
(1889), p. 513.

g. Loeffler, F. Weitere Untersuchungen iiber die Beizung und Far-
bung der Geisseln bei den Bakterien. Centralblatt f. Bakleriologie u.
Parasitenkunde, Bd. VII, (1890), S. 625.

10. Trenkmann, Dr. Die Farbung der Geisseln von Spirillen und
Bacillen. J/dzd., Bd. VIII, (1890), S. 385.

11. Dowdeswell, G. F. Note surles flagella du microbe du choléra.
Annales de Micrographie, T. Il, (1890), p. 377-

12, Moore, V. A. A review of the methods of demonstrating the
flagella on motile bacteria, with special reference to the staining pro-
cesses. American Monthly Microscopical Journal, vol XII, (1891), p.
15.

13. Moore, V. A. Observations on staining the flagella on motile
bacteria. Proceedings of the Am. Soc. of Microscopists, (1891), p. 86.

14. Zettnow, E. Ueber den Bauder Bakterien. Centralblatt f. Bak-
teriologie u. Parasitenkunde, Bd. X, (1891), S. 6.

15. Luksch, L. Zur Differenzialdiagnose des Bacillus typhi abdomi-
nalis (Eberth), und des Bacterium coli communis (Escherich). Cen-
tralblatt f. Bakteriologie u. Parasitenkunde, Bd. XII, (1892) S. 427.

The Character of the Flagella 365

16. Rodet, A., et Roux, G. Bacille d’Eberth et bacillus coli. Expéri-
ences comparatives sur quelques effets pathogenes. Archives de méd.
Expérimentale, T. IV. No. 3, (1892), p. 317.

17. Straus, I. Sur un procédé de coloration, a l’état vivant des cils
ou flagella de certaines bactéries mobiles. Comp. Rend. Société de
Biologie, T. IV, (1892), No. 23. p. 542.

18. Tavel, E. Caractéres différentiels du bactérium coli commune et
du bacille typhique. La Semaine Méd. T, No. 8, (1892), p. 52.

19. Brown, A. P. Staining bacteria to demonstrate their flagella.
The Observer, vol. III, (1892), p. 298.

20. Sternberg, G.M. Manual of Bacteriology. (1892), p. 346.

21 Fraenkel, C., and Pfeiffer, R. Atlas der Bakterienkunde. Tafel
LIV, (1891), No. 11.

22, Migula, W. Bacteriologisches Practicum, (1892).

DESCRIPTION OF PLATE.

The figures in the plate are to illustrate the flagella on these three
species of bacteria as they appeared in stained cover-glass preparations.
The drawings were made by the aid of a Zeiss apochromatic objective,
2 mm., 1.30 n. a. and the measurements were made with the com-
pensating micrometer ocular No. 6. Each germ and its flagella were
carefully measured and in the drawings each micromillimetre is rep-
resented by a millimeter, thus giving a magnification of a thousand di-
ameters. The curves in the flagella were carefully counted and repro-
duced as accurately as it was possible by freehand drawing. The posi-
tion of the flagella was also carefully determined. In the preparation
of the plate care has been taken to avoid extremes. Individual bacteria
have been selected from different fields to represent the various number,
lengths and position of the filaments on the body of the germs as they
appeared in the preparations. A few free, or detached flagella are also
indicated. The drawing of each germ is practically equivalent to a photo-
graph. It is possible to find all of the structures represented in a few
fields of the microscope in a well executed preparation. The germ in
the center of each figure represents the maximum number of flagella on
a single individual. In the left lower corner of each isa drawing of a
clump of bacteria with their flagella. There are a few drawings of bac-
teria (@) with only their periphery and flagella stained.

Fig. 1. Bacillus cholere suis. Drawings made from preparations of
the culture of hog cholera bacteria obtained in the State of Illinois. (6)
A bunch or strand of flagella.

Fig. 2. Bacillus coli communis. Drawings made from preparations
from the culture obtained from the human intestine.

Fig. 3. Bacillus typhi abdominalis. Drawings made from prepara-
tions of the typhoid bacillus which was obtained from the Johns Hopkins
Hospital. The upper right hand corner, enclosed in dotted lines, rep-
resents all of the bacteria and flagella from a single microscopic field.

SC a Se
Me ep:
i

THE LYMPHATICS AND ENTERIC EPITHELIUM
OF AMIA CALVA.

GRANT SHERMAN HOPKINS.

The comparatively small number of investigations upon
the lymphatic system of Fishes and Fish-like Vertebrates ap-
pears the more remarkable when we consider the capacious-
ness and the undoubted importance of this great vasiform
system.

A possible explanation for this lack of attention on the
part of zoologists may be found in the difficulties attendant
on any investigation of these vessels owing to the trans-
parency and delicacy of their walls and the liability of con-
fusing them with the veins. To whom is due the credit of
having first discovered the lymphatic system in fishes, we
will not attempt to decide. Hewson and Monro both claimed
the honor, but it is pretty well established that the lacteals of
a fish were observed more than a century before by Bartholin*
(2) though his description was alloyed with the old error that
they terminated in the liver. It is doubtless true, as remarked
by Abernethy that ‘‘all our knowledge of the absorbing
vessels has been obtained by fragments, and that our future
acquisitions must be made in the same manner.’’ It must be
allowed, however, that the lymphatic system of the lower
vertebrates, especially the osseous fishes, was more completely
exhibited by Hewson (8) than by any of his predecessors or
contemporaries.

Hewson’s three papers on the lymphatic system in birds,
amphibia and fishes, appeared in the Philosophical Transac-
tion for 1768-69. In the paper on fishes he gives a
description of the lymphatic vessels in the Haddock together
with some of the more striking pecularities of this system in

* See References.

368 Grant Sherman Hopkins

fishes, among which are the absence of lymphatic glands and
the incomplete development or entire absence of valves within
the lymphatic vessels. According to Robin (17) Monro was
the first anatomist to investigate the lymphatic system of
selachians. But many of his statements are incorrect as in
several instances he mistook veins for lymphatics. It was
a mistake of this kind that led him to believe that the
lymphatic vessels commenced by free extremities provided
with small orifices. He saw the injected material ooze out
upon the surface of the skin and enteric mucosa without ex-
travasation into the underlying connective tissue and con-
cluded that they commenced by these free openings. The
general arrangement of the large lymphatic vessels in fishes,
as given by Milne-Edwards (12) corresponds with the state-
ments of most anatomists who have written upon this subject.
He divides the system into two portions, one belonging to the
abdominal viscera, the other to the skin, muscles and
neighboring parts. Concerning the latter he says, ‘‘the sub-
cutaneous lymphatic system constitutes, in general, three
principal trunks which have a longitudinal direction, and
which are situated, one on the ventri-meson, the two others
on the sides, in the groove which separates the muscular
masses of the dorsal and ventral portions of the body, and
which can be recognized, externally, because it corresponds
in position to the lateral line. This system of vessels receives
a multitude of secondary branches which ramify under the
skin, and it opens into the veins at its two extremities, 7. e.,
near the base of the cranium and at the base of the caudal
fin.’? At the caudal end each lateral lymph vessel terminates
in a sinus; these sinuses communicate not only with the
caudal vein but with each other as well.

The investigations of Hyrtl (9) upon the cephalic and cau-
dal sinuses of fishes, and the lateral vessels with which they
are connected, led him to the conclusion that these vessels
formed no part of the blood-vascular system but were lym-
phatics. He examined the fluid of the caudal sinus and
found it ‘‘clear as water, having the same properties as the
liquid contained in the lymphatic vessels of other parts of the
body.’’

Lymphatics and Enteric Epithelium of Amia Calva 369

In contradistinction to the statements of the authors above
mentioned, Robin says ‘‘I have satisfied myself by numerous
observations and experiments, that the cutaneous and sub-
cutaneous vessels described by Monro, Hewson, Hyrtl, etc.,
as lymphatics, are veins. .... The division of the lym-
phatics of fishes into superficial and deep or visceral, still
adopted by some modern authors, must consequently be aban-
doned. ‘The first of these classes of vessels does not exist in
this class of vertebrates.’? As the conclusion to his article
Robin turther says, ‘‘the general result of these researches has
been to demonstrate that the subcutaneous vessels which I
have described in the selachians....... as being lym-
phatics, are veins and not lymphatics at all. This conclusion
is found entirely confirmed by the descriptions contained in
this memoir; they prove, indeed, that fishes have no other
lymphatics than the chylous vessels, and those of the peri-
toneum lining the genito-urinary organs and the pericardium.”

So far as I have been able to ascertain, no other writer
shares this opinion. Indeed from the statements of various
authors and from my own observations, I think Robin was
wrong in calling the subcutaneous vessels, veins rather than
lymphatics. Ina specimen killed by pithing, the cephalic
lymph sinus was exposed while the heart was still beating ;
the veins were gorged with blood but the lymph sinus ap-
peared perfectly clear and transparent, and at no time was
blood found in the lateral vessels. In several instances a
clear fluid was seen to run out of the lateral vessel, when cut,
in a fresh specimen.

The arrangement of the lymphatic vesels of Ama calva has
been found to agree, in general, with that of various other
fishes, as described by the several authors, but in some re-
spects there is a marked difference. The system consists of
the two parts, a peripheral or subcutaneous and an ental or
visceral portion.

To satisfactorily demonstrate these vessels they may be in-
jected but the precaution must be taken to first inject the
veins, otherwise the two sets of vessels can not be distin-
guished with certainty. A convenient place for injecting the

370 Grant Sherman Hopkins

veins is in the large caudal vein which extends along the ven-
tral side of theaxon. ‘The tail may be cut off a little cephalad
of the base of the caudal fin and the canula easily inserted
into the vessel. But as the caudal vein sends off branches
into the kidneys, which either break up completely or par-
tially in this organ, the further precaution must be taken to
use for injecting some mass that will pass through these small
vessels into the cardinal veins beyond. Such a mass may be
made by taking 1o grams of gelatin and adding soc. c. of
water ; this is melted over a water-bath and 150 c. c. of water
colored with Berlin-blue, is added. ‘This mass becomes fluid
at such a low temperature that there is little danger of the
gelatinization of the connective tissue of the blood-vessels and
their consequent rupture, when injected, as would be liable to
occur if the injecting mass melted only at a comparatively |
high temperature. For injecting the lymphatics, the follow-
ing mass serves very well. Gelatin, 20 grams; water, 200
c. c.; potassium dichromate, sat. aq. sol. 75 c. c.; acetate of
lead, sat. aq. sol. 75 c.c. ‘The gelatin is melted over a water-
bath ; the hot dichromate is then added after which the hot
acetate of lead is added and the whole mass filtered through
flannel or absorbent cotton.

LATERAL LINE, LATERAL OR MUCOUS CANAL AND LATERAL LYMPHATIC
VESSEL.

In order to avoid any possibility of misapprehension in re-
gard to these three terms it has been thought well to briefly
describe them. The lateral line isa longitudinal line along
each side of many fishes, marked by the structure or color of
the skin, or both. It consists of a row of tubes or pores,
mostly on scales, extending from the head to or toward the
tail. The pores are the ducts of muciferous glands whose
product is excreted on the sides of the fish. (Cent. Dict).

Lateral or Mucous Canal.—In most, if not all, fishes the in-
tegument of the body and of the head contains a series of sacs,
or canals, usually disposed symmetrically on each side of the
middle line, and filled with a clear gelatinous substance. . . .
These sensory organs are known as the “‘organs of the lateral

Lymphatics and Enteric Epithelium of Amia Calva 371

line,’? or mucous canals. (Huxley, Anat. Vert. p. 79). The
lateral lymph vessel is essentially different from the lateral
canal, which has the same direction. If one raises the scales
with the lateral canal situated under them, and if the skin
be cut, there is found in the subcutaneous connective tissue
a small vessel, with delicate walls, lying in the groove which
separates the long lateral muscles of the vertebral column
and so closely connected to the surrounding parts that it is im-
possible to separate them. (Hyrtl, Annales des Sci. Nat. Vol.
20 (2° série), p. 222). This canal is the lateral lymph vessel.
Unlike the preceding it has no openings upon the surface of
the skin.

The main subcutaneous lymphatic vessels of Amida calva
are four in number and are situated, one on each side of the
body, entad of the lateral line, one on the ventri-meson and
one on the dorsi-meson. From the large lateral lymph vessels
many small branches are given off in a penniform manner.
At the base of each pectoral fin is a large lymph sinus. The
branches joining these to the lateral lymph vessel extend dor-
sad and join the latter at the caudal edge of the shoulder-
girdle ; another branch extends from the pectoral to the peri-
cardial sinus. After receiving the branch from the pectoral
sinus, the lateral lymphatic passes under the pectoral arch
and opens into a large lymph sinus (Fig. 10), extending from
the dorsal end of the clavicle* along the dorso-lateral portion
of the cephalic edge of the arch, to which it is closely joined,
and into the base of the cranium. In the cranium the sinus
could be traced readily only to about opposite the base of the
orbit. The opening from this sinus into the veins is at a point
about 1c. m. cephalad, and a very little ventrad, of the dor-
sal end of the clavicle (Fig. 10). The orifice is guarded by a
valve which opens toward the vein. Near the edge of the
clavicle, a little ventrad of the level of the lateral lymph ves-
sel, is another orifice opening from this sinus into the peri-

* The clavicle is the large curved bone with a thick cephalic and thin
caudal border. It extends ventrad and then cephalo-mesad so as nearly
to meet its fellow of the opposite side at the ventri-meson of the throat.
(Parker’s Zootomy, p. 100).

372 Grant Shernan Hopkins

cardial sinus (Fig. 10). The action of the valve at this open-
ing, as determined by insufflation, permits only the ingress of
fluids and it is by this opening, doubtless, that the lymph of
the pericardial sinus enters the lymph sinus of the lateral
lymphatic vessel, and from thence enters the veins.

At the caudal end of the body the lateral lymphatics
terminate in the caudal vein. The correlation of the lymph
and blood vessels at this point is somewhat complex. ‘The
lateral lymphatic extends caudad, nearly or quite as far asthe
dorsal fin, when it suddenly bends at right angles and extends
between the muscles directly towards the meson. Close to
the sides of the vertebrae the vessel opens into a lymph sinus
extending along the side of the axon (Fig. 11, s). Conse-
quent on the dorsal inclination of the terminal portion of the
axon, the lymph sinus lies at an angle tothe general direction of
the lateral lymph vessel. In a specimen measuring 53 c¢. m.,
the sinus was about 1c. m., long and from 3 to 5 millimeters at
its greatest width. At its cephalic end the sinus opens into the
caudal vein. ‘The orifice between the two vessels is closed by
a valve which readily permits the flow of lymph into the
veins but prevents any flow in the opposite direction as was
repeatedly demonstrated by alternate insufflation and
aspiration of the caudal vein. The sinus communicates with
its fellow of the opposite side by at least two small connecting
branches, passing directly from the mesal side of one sinus
into the corresponding side of the other. Joining the lateral
lymph vessel shortly after it turns toward the meson, is a
large branch which extends dorso-caudad to near the dorsal
edge of the caudal fin and then turns cephalad and is con-
tinued along the body as the dorsal lymphatic (Fig. 11, r.).

The correlation of the lateral lymph and blood vessels was
found to be the same on either side of the body.

The lymphatic vessel on the ventral side of the body begins
as a large vessel along the base of the caudal fin, and extends
directly cephalad till it reaches the level of the heart where it
divides into two branches which lie between the pericardium
and the tough fibrous partition separating the pericardial
from the abdominal cavity. On its course, it receives the

Lymphatics and Enteric Epithelium of Amia Calva 373

lymph from the anal and pelvic fins. The sinus at the base
of each of these fins is smaller than the one at the base of the
pectoral. As the vessel approaches the heart it increases in
size measuring, in a large specimen, about a centimeter in
diameter at the point of bifurcation. The two branches into
which it divides merge into the large pericardial sinus which,
as already stated, communicates with the sinuses of the
lateral lymph vessels and thence with the veins. Possibly
there are other openings from the pericardial sinus into the
veins but none were observed. In one instance an anas-
tomosing branch was found extending from the large vessel at
the base of the caudal fin, to the lateral lymphatic, joining
the latter just as it turns toward the meson (Fig. 11, t).

The dorsal lymphatic vessel extends along the dorsimeson
from the caudal end of the body to the base of the cranium.
At the caudal end, as already indicated, it anastomoses with
the lateral lymph vessel, joining it just after the latter turns
at right angles to its longitudinal course, to enter the caudal
sinus. Whether the dorsal vessel bifurcates into symmetrical
branches at its caudal end, can not be positively stated. It is
believed, however, that it does. In one specimen a branch
was found on either side. At the cephalic end the vessel bi-
furcates at the base of the cranium, each branch extending
laterad to join the large lymph sinus, on either side, which
has already been described as extending to near the base of
the orbits and into which the lateral lymphatics open. Along
the base of the dorsal fin the vessel is somewhat larger than it
is farther cephalad. From the relative size of the two ex-
tremities of this lymphatic, one might judge that the course
of the lymph was caudad, 2. e., that this vessel emptied at its
caudal rather than at its cephalic end. ‘The fins are well sup-
plied with lymphatics. According to Trois (22), there are two
quite large vessels at the sides of each fin-ray. The vessels
of adjoining rays are connected by innumerable small anasto-
mosing branches.

THE VISCERAL LYMPHATICS.

The anastomosis of the visceral with the subcutaneous
lymphatic system appears to be slight. Only a few of the

374 Grant Sherman Flopkins

smaller branches of the former were filled, however well the
latter might be injected. Doubtless by long continued injec-
tion of the subcutaneous vessels all the visceral lymphatics
could be filled, but a more expeditious method is to inject, by
means of a rather coarse hypodermic needle, into one of the
small vessels that extends along the intestine or directly into
one of the large lymph spaces. It may be said, however,
that nothing was found equal to the flexible blow-pipe as a
means of demonstrating the course of the lymphatics and
their connections with the various trunks. Indeed it is be-
lieved that certain of the valves at the orifices could not have
been satisfactorily demonstrated in any other manner.

The lymphatic vessels which collect the lymph from the
abdominal viscera and convey it to the veins, may, for con-
venience of description, be divided into two portions of which
one consists of three large sinuses and the other of the nu-
merous small vessels emptying intothem. ‘Two of the sinuses
are situated on either side of the cesophagus immediately cau-
dad of the septum between the abdominal and pericardial cay-
ities ; the other extends along the walls of the air-bladder, on
the right side.

The sinuses along the cesophagus are separated from each
other and also covered on their ventral side by the liver and
the pyloric end of the stomach. ‘The left lobe of the liver is
joined to the sinus by a broad fold of peritoneum which is at-
tached to the latter along its middle portion. Of the two
sinuses the left one is much the larger. In a specimen meas-
uring 53.c. m. in length, it was nearly 8c. m. long and at
least 2c. m. wide. Its general form is cylindrical. It ex-
tends as far caudad as the liver. In general, its attachment
to the enteron is along the dorso-lateral portion of the cesopha-
gus and stomach, but it does not extend as far caudad as the
latter ; it is also closely joined to the adjacent walls of the air-
bladder. From the caudal end of the sinus several lymphatic
vessels ramify in a rich net-work over the adjacent walls of the
stomach and air-bladder. The lymphatic sinus on the right
of the cesophagus has the same general form as the one on
the opposite side. It is about 5 c. m. in length and 1% c. m.

Lymphatics and Enteric Epithelium of A mia Calva 375

in diameter at its widest point. It extends nearly as far cau-
dad as the cholecyst. The cephalic half is covered by the left
lobe of the liver; the other half by the cholecyst, to which it
is closely united. Several ducts open into the caudal end of
the sinus. One duct passes obliquely across the dorsal side of
the duodenum and pyloric end of the stomach, and joins the
left lymphatic sinus at the apex of the interval between the
cesophageal and pyloric portions of the stomach, 7. ¢., near
the caudal end of the sinus. his is the only communication
that was found between the two sinuses. Another lymph duct,
much larger than the preceding, passes ventro-caudad be-
tween the pyloric portion of the stomach and the duodenum.
Upon reaching the ventral side of the latter it extends directly
caudad as far as the spleen where it divides into several small
branches which accompany the blood-vessels along the sides
of the intestines ; along some of the folds of the intestine as
many as three lymphatic vessels were found. As the duct
reaches the ventral side of the duodenum, it gives off a small
branch to the ventral wall of the stomach; the diameter of
the main duct itself, along its cephalic portion, is fully Ye @ mi:

The last to be mentioned of the three abdominal sinuses, is
situated on the right side, along the walls of the air-bladder
and stomach. It is fusiform, measuring in a specimen 42 c. m.
in length, a little over 7c. m. from end to end and about 1
c.m. in diameter at its widest point. It opens into the right
lymph sinus, on the dorso-lateral side, near the base of the
cornu of the air-bladder. There appears to be no valve at
this orifice; the injecting material, as well as air, readily
passed from the one sinus into the other. At its caudal end
it anastomosis with one of the ducts extending along the
duodenum ; many small branches enter it from the stomach
and air-bladder. ‘The lymph from the right and left lobes of
the liver enters the corresponding sinus. In only one or two
instances were trabeculze seen in the lumen of these sinuses.
Some of the vessels of the intestines anastomose with the
peripheral lymphatic system at the caudal end of the abdo-
men.

As stated before, the large fusiform sinus lying along the

376 Grant Sherman Hopkins

side of the air-bladder, opens into the large lymph sinus at
the right side of the cesophagus. The termination of the en-
tire visceral lymphatic system isin the great veins, or ducts of
Cuvier, on either side of the heart.

From each of the great lymph sinuses, along the cesopha-
gus, there extend little bay-like prolongations which open
into the venous trunks, as just mentioned. In one specimen
three of these openings were seen on each side ; possibly there
were still other smaller ones. The mechanism of the valve-
like structures which close these orifices needs further study.
The lymph sinuses were repeatedly filled with air, yet but
little, sometimes none, was seen to escape into the veins;
liquids seemed to pass somewhat more readily. It was found
practically impossible to pass a beaded bristle from the lymph
sinus into the veins, or the opposite, although the orifice is
much larger than the bristle. When the sinuses are dis-
tended with air, the thin walls around the openings form
slight, rounded swellings, which project into the lumen of the
blood-vessel. Immediately around the orifice the walls are
somewhat thickened, and as nearly as could be made out
these thickened portions over-lap each other, in somewhat the
same way as would result if a slit were made in a hollow
sphere and one edge drawn over the other. This over-
lapping of the edges of the orifice would account for the difh-
culty of passing a bristle through the opening.

THE ENTERIC EPITHELIUM.

The enteric epithelium of this most teleosteoid (in appear-
ance) of Ganoids, as it has been called, exhibits certain mor-
phological features peculiar, so farasat present known, to the
group Ganoidei. ‘The buccal cavity is covered by a stratified
epithelium ; the superficial layers are flattened while the
deeper lying cells are more nearly columnar ; the intermediate
cells gradually merge from the one into the other as is com-
mon with this kind of epithelium. At irregular intervals the
epithelium is pierced by large conical or dome-shaped struct-
ures which project to the free surface. ‘These doubtless cor-
respond to those structures which according to Wiedersheim

Lymphatics and Enteric Epithelium of Amia Calva 377

“function from the amphibia onwards as organs of taste,
while in fishes they probably serve as tactile organs.’’
(Weidersheim, Comp. Anat. of Vertebrates, p. 167). Farther
caudad the surface layer of cells gradually becomes columnar
with many interspersed beaker-cells. Some distance cephalad
of the pneumatic duct-opening the stratified is replaced by a
columnarepithelium. ‘The transition between the two is quite
sudden there being scarcely any overlaping of the two epithe-
liums. From this point to within about 2c. m. of the pylorus,
the epithelium is ciliated. Incidentally, it may be mentioned
here that ciliated epitheliums have been found in several other
regions of the body. In the air-bladder, ciliated ceils were
found from one end of the organ to the other. ‘The cells are
columnar but the cilia are somewhat longer than in the ceso-
phagus or stomach. The ciliary currents extend cephalad or
toward the opening of the pneumatic duct. The epithelium
of the nasal cavity is also ciliated ; the cells are of the same
general form as those of the air-bladder and stomach but the
cilia are much longer than in either of the last mentioned
organs. It is stated in the Cyclopzedia of Anat. and Physiol.
(Vol. I, p. 633), that according to Purkinje, Valentin and
Steinbuch, the presence of bile arrests the motion of cilia.
This is incorrect, in the present instance at least, for cilia were
found moving vigorously immediately after emptying the chole-
cyst of its contents. Ciliated cells were found throughout
the whole length of the vesicle and its long convoluted duct.
The cilia are quite long and easily seen in both fresh and
hardened specimens. The currents induced by the cilia ex-
tend toward the opening of the duct.

To form some idea of the rapidity with which foreign bodies
are carried along by cilia, a clot of blood was placed on the
cesophagus at the level of the pneumatic duct opening ; at the
end of five minutes the clot had been carried caudad a distance
of 4% c.m. Farther caudad, the clot moved much more
slowly. At the caudal end of the cesophagus isa short region
occupied by rather short, broad follicles lined by columnar
ciliated cells ; the true gland cells are first met with some dis-
tance caudad of the pneumatic duct opening.

378 Grant Sherman Hopkins

According to Schultze (20), the epithelial cells of the stomach
in all vertebrates, are open, 7. ¢., the free ends of the cells are
not covered by a cell-wall. He thinks that the mucus which
these cells secrete is for the purpose of protecting the cells
themselves from the digestive action of the secreted fluids.
Brinton (3), also seems to hold the same view. Hesays, ‘‘The
protection of the stomach from its own secretion is effected
mainly by the salivary and other secretions which enter it

from the cesophagus and the duodenum. . . . For units of
mucous membrane, Fishes seem to have the most powerful
gastric digestion.’’ These statements appear somewhat un-

satisfactory from the fact that in the American Ganoids, at
least, the ciliated character of the epithelium would tend
strongly to preclude the formation of a distinct mucous coat
over the surface of the stomach. But apart from this, it is
believed that the vital properties of the cells are sufficiently
potent to withstand any deleterious effects which the gastric
secretions may possibly have upon them. Edinger (6), thinks
that the functions of the mucus are to thin the chyme and to
form a protective covering over the hard indigestible bodies,
as sand, shells, etc., which find their way into the stomach.
He says that such foreign bodies, surrounded by a tough mass
of mucous, are frequently found in the intestine. Ebstein (5),
found open as well as closed cells and is of the opinion that
during digestion the membrane of the closed cells is ruptured.
In all the specimens examined by the writer, both open and
closed cells were found.

The surface epithelial cells of Amia’s stomach are very
slender and the attached ends are continued into long thread-
like processes which intertwine with the subjacent mucosa.
As already stated, ciliated cells were found uninterruptedly
from the cesophagus to within about 2c. m., of the pylorus ;
scattered among these were many open beaker-cells. From
the open end of many of the latter a mucous mass of varying
size was often seen projecting some distance beyond the free
ends of the cells. At the cardiac end of the stomach, the
gastric glands appear as short tubes, at the base of the follicles
mentioned above ; they, however, rapidly increase in length,

Lymphatics and Enteric Epithelium of Amia Calva 379

and over the middle portion of the stomach constitute the
greater part of the tubule. As the pyloric region is approached
the glandular part decreases in length and disappears
about 2c. m, from the pylorus ; from this point to the pyloric
valve the glands are lined with cells like those forming the
surface epithelium of this region, only shorter. In the
cardiac region the mouths of the glands are short and are
lined by ciliated cells (Fig. 4).

The cells of the body of the gland are, for the most part,
cubical in longisection of the gland, but for a short distance
below the mouth the cells are more nearly cylindrical in out-
line. Several glands may open into a single mouth. In fig.
4 it will be noticed that the cells lining the mouth of the
gland are placed obliquely to its long axis. Frequently
cells were seen so bent that the angle formed equaled at least
a right angle. In all cases the convexity of the cells pro-
jected towards the exit of the gland; the attached ends of
the cells reached a much lower level than the opposite ends.
In the pyloric region the glands are more widely separated
from each other; the lining cells of these are situated at
nearly right angles to the long axis of the gland. ‘Towards
the pyloric valve the glands become shorter and finally dis-
appear near the free edge of the valve. Cilia were not found
in the pyloric glands. Near the free edge of the valve-like
structure between the stomach and intestine, the characteristic
cells of the intestine appear (Fig. 9). They are slender and
the basal end is continued into a long thread-like process.
The striated border of the cells is very distinct. The varying
levels at which the large oval nuclei are situated, give to the
epithelium, when viewed in section, a stratified appearance
(Fig. 7). The most remarkable feature of the intestinal
epithelium, of Amia, is the presence of cilia in the rectum
(Fig. 7). The epithelial cells of this portion of the intestine
are of the same form as in other parts, but somewhat shorter.
The beaker-cells are numerous and their theca are short and
rounded. Ciliated cells were found only within a small area
immediately caudad of the spiral valve. They may be
demonstrated much more easily and satisfactorily in a per-
fectly fresh condition than after hardening.

380 Grant Sherman Hopkins

SUMMARY.

1. The subcutaneous lymphatic vessels terminate in lym-
phatic sinuses at either end of the body. The lymph sinuses
at the base of the cranium empty into the jugular veins.
The pericardial lymph sinus opens into the preceding, the ori-
fice between the two sinuses being guarded by a valve; the
flow of lymph is from the pericardial into the cephalic lymph
sinus. At the caudal end of the body the lymph sinuses empty
into the caudal vein. ‘These sinuses are considerably smaller
than the cephalic ones.

2. The visceral lymphatic system is more voluminous than
the preceding. In addition to the small vessels extending
along the intestines, etc., there are three large lymph sinuses
situated, one along the right side of the air-bladder, and one
on each side of the cesophagus. The termination of the ab-
dominal lymphatics is in the ducts of Cuvier, there being sev-
eral openings from each of the lymph sinuses, at the sides of
the cesophagus, into the great venous trunks.

3. A ciliated epithelium was found over the greater extent
of the stomach and in the rectum; over the whole extent of
the cholecyst and its duct ; the air-bladder and the nasal cavity.

Thanks are due Prof. Gage for suggesting the subject of
this paper, and for kindly criticism of the same.

ITHACA, N. Y.
August 8, 1893.

REFERENCES.

x. AGassiz ET Vocrt. Anatomie des Salmonés. Mémoires de la Soci-
été des science naturelles de Neuchatel. 1845.

2. BARTHOLIN, THOM. De Lacteis Thoracicis in Homine Brutisque
nuperrimé Observatis, Historia Anatomica, p. 70, I2 mo. London,
1652.

3- BRINTON, W. Experiments and Observations on the structure and
function of the Stomach in the Vertebrate Class. Proc. Roy. Soc.
Lond., 1860-62. xi, 357.

4. CuvIER. Anatomie Comparée. Tome VI. Paris. 1839.

5. Epstein, W. Beitrag zur Lehre von Bau und den physiologischen
Funktionen der sogenannten Magenschleimdriisen. Arch. fur mikr.
Anat. VI. 1870.

G6. EDINGER, L. Ueber die Schleimhaut des Fischdarmes, nebst Be-
merkungen zur Phylogenese der Driisen des Darmrohres. Arch. fur
mikr. Anat. Bd. XIII, 1877.

4. FOHMAN. Das Saugadersystem der Wirbelthiere. 1° Heft. 1527.

8. HEwson, W. Works. 1846.

9. HyrtL. Ueber die Caudal-und Kopf-Sinuse der Fische, und das
damit zusammenhdngende Seitengefass-system. Miiller’s’Archiv fur
Anat. u. Physiol. 1843. Trad. dans les Annales des sciences nat.
22 serie, t)xx.

10. KiLBorNE, F. L. Preliminary Note on the Lymphatics of the
Common Bull-head, Amiurus catus. Proceed. Amer. Asso. Ady. Sci.
Thirty-third meeting. Philadelphia, Penn., 1884.

11. LEvpIG. Anatomisch-histologische Untersuchungen iiber Fische
und Reptilien.

— Lehrbuch der Histologie des Menschen und der Thiere.
— Zur Anatomie und Histologie der Chimera monstrosa. Mul-
ler’s Arch. fiir Anat. und Physiol. 1851.

12. MILNE-Epwarps. Lecous sur la Physiologie. TomeIV. 1859.
Pp. 471-480.

IZ. Monro, A. The Structure and Physiology of Fishes, explained
and compared with those of man and other animals. Lond. 1785,
in folio.

14. Morkeau, E. Histoire Naturelle des Poissons de la France. 1881.

15. MULLER, J. Untersuchungen iiber die Eingeweide der Fische.
Mém. de l’Académie de Berlin pour 1843.

16. OWEN. Anatomy of Vertebrates. Vol. I. 1866.

17. RosBIN, C. Mémoire sur l’anatomie des lymphatiques des Torpilles
comparée 4 celle des autres Plagiostomes. Jour. de1’Anat. et Physiol.,
etc. Paris, 1867, IV, pp. 1-34, 3 plates.

18. Rosin. Sur les vaisseaux lymphatiqnes des Poissons. Arch. gén.
de méd., partie anatomique, 1545.

382 Grant Sherman Hopkins

— Note sur le systéme sanguin et lymphatique des Raies et des
Squales. Jour. de l’Institute, 1845, t. xiii.

IQ. SAPPEY, PH. C. Etudes sur l’appareille mucipare et sur le systéme
lymphatique des Poissons. Paris. 1880.

20. SCHULTZE, F. E. Epithel und Driisen-Zellen. Schultze’s Archiv.
Bd. 111. 1867.

21. STANNIUS UNDSIEBOLD. Handbuch der Zootomie, zweite Auflage,
p bee

22. Trois, E. F. Contribuzione allo studio del Sistema Linfatico dei
Teleostei. Atti del reale Istituto Veneto. 5 serie, Tomo, 6. Dis-
pensaI-5. pp. 401-418 Plate 1. 1879-80.
— Contribuzione allo studio del Sistema Linfatico dei Teleostei.
Ricerche sul sistema Linfatico Dei Gadoidei. pp. 955-59. 1881-2.
—— Nuovi Fatti risguardanti La Storia del Sistema Linfactico dei
Teleostei. Atti del reale Istituto Veneto. 5 serie. Tome 4. Dis-
pensa I-5. pp. 579-608.

DESCRIPTION OF PLATES.

PLATE I.

The outline of the figures, except 10 and 1m were drawn by aid of
Abbe’s camera lucida. Details were put in free-hand. Objectives used
were Leitz Nos. 2, 5, 7, and 7’; oil immersion. Oculars Nos. 1 and 3.
All figures, except I, 2, 10 and 11 are drawn on the same scale.

Fic. 1. Section oP stomach showing the relative thickness of the
different coats. a. mucosa. b. Submucosa and muscularis mucosa.
e. Circular muscular layer. d. Longitudinal muscular layer.

Fic. 2. Gastric gland.

Fic. 3. Epithelial cells of stomach. a. Ciliated cells. b. Beaker-
cells with mass of exuded mucus.

Fic. 4. Mouth of gastric gland showing the ciliated epithelium with
which it is lined; also two glands opening into a single mouth. a.
Beaker cell.

Fic. 5. Transection of gastric glands.
Fic. 6. Longisection of gastric gland.

PLATE II.

Fic. 7. Ciliated epithelium of the rectum, showing ciliated and
beaker-cells and the nuclei at various levels.

Fic. 8. Cells of rectum as seen on end. b. Columnar cells. c.
Beaker-cells.

Fic. 9. Epithelial cells of intestine showing form of cells and striated
border. d. Beaker-cell.

Fic. to. Diagram of head of Amia showing the connection of the
subcutaneous lymphatic system with the veins ; the operculum has
been removed. a. Pectoral arch. b. Cephalic lymph sinus. c. Jugn-
lar vein. d. Duct of Cuvier. e. Lateral lymphatic. 1. gill. p. Pec-
toral fin. s. Serrula. By looking closely at the diagram of the lymph
sinus, the connection with the vein may be seen. Caudad of this is
another opening into the pericardial sinus; the pericardial sinus itself
is not represented, only the orifice between the two being figured.

Fic. 11. Diagram showing the relation of the subcutaneous lymphatic
and venous system at the caudal end of the body. a. Dorsal fin. b.
Caudal fin. d. Anal fin. e. Axon. i. Caudal vein (the caudal artery
has been omitted). 1. Lateral lymphatic vessel; the one on the oppo-
site side is indicated by broken lines. s. Caudal lymph sinus. The
opposite one is indicated by dotted line. o. Lymph vessel at base of
caudal fin. This is continuous with the lymphatic along the ventri-
meson as shown in diagram. t. Connecting branch between the lym-
phatic vessel at the base of caudal fin and the lateral lymphatic vessel.
r. Branch connecting the dorsal and lateral lymphatic vessels. un. Dor-
sal lymphatic vessel. v. Lymph vessel along ventri-meson.

HOPKINS. FI AGIE Sle

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HOPKINS. PLAN ICIS, UC

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BRAIN PRESERVATION, WITH A RESUME OF SOME
OLD AND NEW METHODS.

By PIERRE A. FISH.

The brain, the organ of thought, complex in structure, the
great co-ordinator of bodily functions, the master and yet the
servant of the animal economy, has been the last of the vis-
cera to receive careful preservation. The ancient Egyptians
in their most perfect embalments ‘‘ drew the brain through the
nostrils partly with a piece of crooked iron and partly with
the infusion of drugs.’’ The other viscera upon removal were
carefully cleansed and after proper treatment were replaced in
the body, the brain apparently being the only part rejected.

The summary treatment of this important organ and the
bad precedent thus established by the Egyptians retarded for
along time the development of any progressive ideas in this
direction. From the time of the Egyptians down to near the
close of the seventeenth century no advance but actual retro-
gression occurred in the art of preservation ; this being due to
some extent to the indifference of the nations in power at that
time, but chiefly to the great religious Opposition toward any-
thing pertaining to science. During this dark period of
scientific stagnation much has been lost that may never be
recovered.

The crude and erroneous descriptions of the early anato-
mists justify the beliefthat their methods were but little superior
to those that preceded, but the progress in those early years
of embalming the body, marks also an advance, slight and
inefficient perhaps, but nevertheless an advance, in the pres-
ervation of the brain itself ; particularly so when the injection
method came into use. Toa Hollander, Frederic Ruysch,
Professor of Anatomy, at Amsterdam from 1655 to 1717, be-
longs the honor of having originated and perfected this method
to such an extent that his specimens are said to have been
wonderfully life-like and to have aroused the admiration of
the people of his age. The formula of his preservative was
not divulged and the secret of its preparation died with him.

386 Pierre A. Fish

William Hunter did much to extend the practice of injection
by producing some very beautiful specimens and the impetus
thus given by these early anatomists has brought the method
down to us with but few if any radical changes.

Admirable as these results were concerning the body asa
whole, it became apparent that they were quite inadequate
when a more thorough and accurate knowledge of brain mor-
phology was demanded, thus it came about that greater care
was used in the removal of the brain and special methods of
treatment were devised, and the importance of technique be-
came more and more emphasized, especially so within the last
two or three decades.

The consistence of the brain coupled with the difficulty of
its removal renders it a difficult organ to preserve. History
gives good evidence that the advance in the knowledge of
brain structure has been largely dependent upon improved
methods of manipulation.

The purpose of hardening is to bring the brain into a proper
condition for the continued study of either its fine or gross
anatomy, the former usually requiring some special care in
methods and after-treatment which may be dispensed with in
the latter without apparent detriment.

For the study of the gross anatomy either wet or dry prepar-
ations may be available. The preference generally being
given to the wet since they are more easily and quickly pre-
pared and because they admit of further and careful dissection
at any time after once being well hardened. A shrinkage in
the tissues must necessarily occur during this process but it is
not usually carried so’ far asin the case of the dry prepar-
ations. Nor is there such an unnatural color unless some
colored preservative is employed. But there is the disad-
vantage of a possible ruination of the specimens by over-ex-
posure to the air, evaporation or deterioration of the preserva-
tive and a consequent expense in renewing the same.

For the study of surface anatomy and of certain parts dis-
sected out before the specimen is ‘‘dried,’’ there is no reason
why, if successfully prepared, the dry method would not
answer most needs and have the further advantage of re-
maining permanent in the air.

Brain Preservation 387

Reil’s method of preparing the brain : *

‘“Of the methods which I have employed in preparing brains
those contained in the following directions answer best: (1).
Let the brain be hardened in alcohol and then placed in a so-
lution of carbonated or pure alkali, in the latter two days, in
the former for a longer period, and then again hardened in
alcohol if thus rendered too soft. The advantage of this
method is that the fasciculi of nervous matter are more readily
separable and the brown matter more distinguishable from the
white than after simple maceration in alcohol ; the gray mat-
ter is rendered by the alkali of a blacker gray and assumes the
consistence of jelly. (2). Let the brain be macerated in al-
cohol in which pure or carbonated potass. or ammonia, has
been previously dissolved ; the contraction of the brain is
lessened by this process. (3). Let the brain be macerated in
alcohol from six to eight days and then its superficial dissec-
tion commenced, and the separation of the deeper parts con-
tinued, as the fluid in which the brain is kept immersed, pen-
etrates its substance. This method appears to me better than
the preceding, and would very likely be improved if the al-
cohol were rendered alkaline. The fibers in a brain thus pre-
pared are more tenacious than otherwise, and the deeper parts
are sooner exposed to the influence of the alcohol.”’

These methods are applicable chiefly for the macroscopic
study of commissural relations and the yeneral direction of
fibers.

J. Muller in 1834 recommended the use of creosote water
for the preservation of the brain and myel.

Alcohol is the oldest and most universal preservative em-
ployed. Ithas good ‘“‘fixing’’ properties but needs consider-
able attention in order to produce the best results. For fixing,
it is frequently used in conjunction with some of the various
salts, or in case some non-alcoholic fixer is used, it supple-
ments or completes the hardening thus begun. As a preserv-
ative it is generally used at the ordinary commercial strength
—ninety to ninety-five per cent., although for most tissues
eighty or even seventy-five per cent. seems to suffice.

On account of the continuous dehydration and the struct-

* Mayo’s translation of Reil’s Eighth Essay.

388 Pierre A. Fish

ural changes induced thereby, it is advisable to use not
higher than ninety per cent. The great and unequal attrac-
tive power of alcohol for water, renders it necessary to begin
with the lower grades. Otherwise the rapid withdrawal of
the water before the alcohol can replace it, will cause shrink-
age and the tearing or breaking down of the tissue. Immer-
sion of a large specimen ina limited quantity of strong al-
cohol is likely to induce a rapid hardening of the surface,
forming a crust through which the alcohol may cease to pene-
trate, causing a consequent maceration of the interior.

For general utility, economy and certainty of result, no re-
agent excels potassium bichromate in its action on nervous
tissue. It is said that attention was called to this salt for
hardening purposes by a Mr. Savory, some thirty or more
years ago”. It is commonly used in a simple two or five per
cent. solution or in the form of ‘‘ Mullers’”’ or ‘‘ Erlicki’s’’
liquids. The simple solution has of late come into greater
prominence.

It is inexpensive ; it hardens slowly but thoroughly, with a
minimum of distortion and leaves the specimen in a state of
good consistency even if its action is prolonged. Its applica-
tion is general; it preserves the contours of large and
irregular areas for the morphologist and maintains the proper
relations of the structural elements for the histologist. A
little chromic acid (one or two drops of a one per cent.
solution) added to each thirty cubic centimeters of the
bichromate will do no harm and will quicken the hardening. ™
All chromic salts impart a disagreeable and abnormal color to
the specimens and for some purposes render them quite un-
desirable. :

This” it is said may be obviated to some extent by harden-
ing the tissue in the following mixture :

Potassium! bichromatessonie.-. ..:.. “Ol@natiis
Potassium nitrate V2 eee. Ge hasnt
Water. sty, Gai Ren ete Re rn

After-treatment with absolute alcohol is recommended by W.
C. Krauss for decolorization. Unna advises peroxide of
hydrogen. Lee mentions chloral hydrate in a one per cent.

Brain Preservation 389

solution, but this is declared by Gierke to be prejudical to the
preservation of the tissues.

Corrosive sublimate*is useful as a fixative either in an
aqueous or alcoholic solution ; it is more soluble in the latter.
Chaussier at the beginning of the nineteenth century recog-
nized the antiseptic properties of this salt and since that time
it has been quite extensively used asa preservative. Pro-
fessor Robert Garner* with regard to his method says: ‘‘ We
let the brain fall from the skull into a hardening solution
of bichloride of mercury, the strength about six ounces of
the salt to the half gallon of water making a fluid of about
1.038 sp. gr. or the same as the brain itself, in which it
consequently remains suspended in mid-fluid without pressure
on any of its surfaces and becoming hard and solid without
the contraction which takes place when spirit is used. ”’

Richardson” gives the following formula for the central
nervous system :

Meremrc chiloridssigi/ 24g) 0S k vae 2 L2uetanis
Alcohol (sp. gr. a De Rah bi abe Ah Ee OUCH
Hydrochlorre acid: 2.) 2! .-. SUMMED erEC?

There are various inconveniences Siete the use of this
reagent, not the least of which are its corrosive action on
anything metallic making it very necessary that all traces of
it be washed out before any dissection is undertaken ; its
caustic action on the hands is very marked; precipitates
often occur in the tissue and are a source of considerable
annoyance to the histologist. Camphor renders the sublimate
more soluble and if the tissue after its sublimate bath be
brought into alcohol containing camphor the washing out of
the salt is considerably expedited. Tincture of iodine is
another agent useful in this respect. A little of it isadded to
the alcohol and as it dissolves out the sublimate, the color of
the solution is weakened and the iodine is gradually renewed
until the color no longer fades. The alcohol should be
changed frequently. If the sublimate is not thoroughly re-
moved from the tissues they become brittle.

The origin of the use of Zinc chlorid for neurological pur-
poses is enveloped in considerable uncertainty. Bischoff* in a

- *Die Grosshirnwindungen des Menschen. Minchen. 1868. S. II.

390 Pierre A, Fish

note says: ‘‘ From a note in Gratiolet (Mémoire sur leplis
cérébraux del’homme. Paris. 1854, p. 11.) it is to beseen that
a Parisian modeller, Stahl, likewise used the zinc chlorid for
hardening brains, in order to make a cast of the same after-
ward, but it does not appear that Gratiolet employed the same
process in his anatomical researches. ’’ Bischoff himself had
used it for some years previous to 1868.

It is a deliquescent salt and specimens should not be left too
long in its solution lest they soften. The hardening is con-
tinued in alcohol. Aqueous solutions are generally used since
enough of the salt may be dissolved to support the brain.
Broca’ (1879), was perhaps the first to recommend it in an al-
coholic solution (ten per cent.). It acts here as a very strong
dehydrant, but its action is even if rapid, and with careful
treatment no marked distortion results. It has also proven
eminently satisfactory for histological work, but for this a five
per cent. solution is apparently just as efficacious as the strong-
er. The specific gravity of a saturated alcoholic solution is
not great enough to buoy the brain, and a bed of cotton is
therefore necessary.

Glycerin makes a very efficient preservative. Itis, however,
generally utilized as an adjunct in methods more or less com-
plex or for the immersion of specimens that have already been
hardened.

Nitric acid in a ten or twelve per cent. solution has also
been recommended; the specimen is to be immersed from
twelve to fifteen days and turned frequently as the liquid is too
dense to admit of its being entirely covered. This reagent is
said to give the /oughest of preparations.

Experiments were made in May, 1892, to determine ap-
proximately the relative loss of weight and girth of a number
of sheep brains prepared in different ways. The girth was
ascertained by measuring transversely around the brain at
the level of the temporal lobes. This as well as the weight
was determined at three stages during the course of hardening :
first, when fresh ; second, the intermediate stage, or before
the specimen was brought into alcohol ; third, after immersion
in alcohol for a longer or shorter time. The accompanying
table shows very concisely the results thus obtained.

391

Brain Preservation

WEIGHT. GIRTH.
FLUID.
Fresh, IMECne” | —Aleohal: Fresh. Te Alcohol.
diate. diate.

1. Zine chlorid,. .. . . 200grams,

70 per cent. Alcohol . 3000 c. ¢c., 114 grams | 87 grams 78 grams

Glycerin, ©. =-i5: 2 1200.c. ¢.,~ | May-2)"92. || May9;92; | May-12. ao ISeeee T4s5er

Sp. gr. 1.05. a

2. I0 per cent. aqueous solution of | 112 grams | 93 grams | 67 grams

Zinc chlorid, Sp. gr. 1.14,.. . . May 2. May 24. June I1. HONG Ue aa 14:5:
3. Equal parts ofa saturated aqueous a

sol. of Potassium bichromate anda | 7 rh pee S poets qaneat 5 16.5 cm. 15.7 cm. Ye) (hol.

Ioprct. aqueous sol. of Zinc chlorid. eas Wee: ;
4. Saturated aqueous solution of Cor- | 112 grams | 118 grams | 76 grams

rosive sublimate, Sp. gr. 1.05, . May 2. May 24. June II. 1S; ex: TG Oscus: Be ears
5. Equal parts of saturated solutions

of Potassium bichromate and Cor- oe ea a SEAS ilo 1S eae 15.9 cm. 16.5 cm. TAs cn

rosive sublimate, (aqueous) . . See eyes: Janes
6. Saturated aqueous solution of Po- | 101 grams | 115 grams | 94 grams

tassium bichromate, Sp. gr. 1.06, May 2. June II. Sept. I9. poe Aces: “pal gE nS: eee

392 Pierre A. Fish

The brain “‘fixed’’ in fluid No. 1 did not sink to the bottom
of the vessel until after six days. Within ten days it had lost
36 grams in weight, and 1.9 centimeters in girth, and had be-
come slightly distorted. The specimen in fluid No. 2 floated
for more than a week; it also became somewhat distorted.
The loss of weight was 45 grams, of girth 2.3 centimeters,
being greater than in any of the others. Fluid No. 3 was
very rapid in its action and produced a very firm preparation.
The color was considerably lighter than in the ordinary bi-
chromate specimens. The loss of weight was 39 grams, of
of girth 1.3 centimeters. It should be noted with regard to
fluid No. 4, that the weight increased 6 grams at the interme-
diate stage and that the girth was exactly the same as when
fresh. At the third stage, however, there was a loss of 36
grams in weight, andof 2 centimeters in girth, due without
doubt to the re-dissolving of the sublimate in the alcohol.
Fluid No. 5 gave a better final test than did any of the pre-
ceding. ‘There was an increase of 8 grams in weight and of
0.6 centimeter in girth at the intermediate stage. The loss
of weight was 25 grams and of girth 0.6 centimeter. ‘Treat-
ment with fluid No. 6 left the brain nearest to its original
weight and girth. There was a gain of 14 grams in weight
and of 0.7 centimeter in girth at the intermediate stage. Af-
ter more than four months from the date of its first treatment
it had lost only 7 grams in weight and had gazzed 0.1 centimeter
in girth. ‘The bichromate is nearly insoluble in alcohol, and
once having penetrated the tissue thoroughly, it remains ; the
replacement of the natural water of the tissues is so gradual
that there is little or no chance for shrinkage, while the al-
cohol afterward helps to keep the salt in place if kept in the
dark (Virchow). ‘The alba and cinerea are quite markedly
differentiated ; and there always exists the abnormal but char-
acteristic chromic color.

An ideal preservative would be one of about the same
specific gravity as the brain itself, replacing gradually the
natural fluids of the tissue with a simple fluid, or with a solu-
tion of some salt of equal density, and not markedly chang-
ing the natural color or size of the specimen.

Brain Preservation 393

There are two liquids which will cause the brain to retain
approximately its normal size; one is glycerin which,
after it has thoroughly infiltrated the hardened tissues, causes
them to absorb moisture from the atmosphere and the natural
fluid is thus artificially replaced by means of this hy-
groscopic agent. There must, however, be some limit to
the preservative action, and the time may eventually
come when enough water will have been absorbed to cause
considerable deterioration. The other liquid is potassium bi-
chromate which, as noted in the table, caused an actual
“bloating ’’ of the tissue, increasing both the weight and
girth of the specimen, and imparting an undesirable as well
as an unnatural color. The pia is a more or less inelastic and
pervious membrane, and while on the one hand it may retard
the penetration of the fluid, it serves a little later, in the case
of the bichromate to restrain the ‘“‘bloating’’ and keep the
tissue within bounds. The pressure either from without or
within, would tend to disturb the normal relations of the his-
tological elements.

Brains from animals of the same species react differently
although subjected to exactly the same course of treatment.
The density of the tissue, the age and condition of the sub-
ject, the temperature and many other factors equally impor-
tant, are causes which contribute to these varying results.

After considerable study and experimenting a fluid was de-
vised, which, though not ideal in its effects, seems to answer
the requirements of economy, fixation of the structural ele-
ments, differentiation of tissue, a minimum amount of distor-
tion, firmness of texture, and rapidity of action.

The formula is as follows:

Be aI ie cra ea) Sg 5) cope alles cg OOUS: CS
Oe Pe MeO usta ts, HOR auld ann Gs 400 ¢. Cc.
RTCA A bah hal cia bio) wd ca BOVE YC
PINS OTUOTAR Ee kh e Side nen BO grams.
Sodium chiorid......... . 20 grams.

The specfic gravity of the mixture should be about Of, a
little greater than that of the brain itself (1.038). The

394 Pierre A. Fish

slightly greater density of the fluid is believed to be more ad-
vantageous than otherwise, since it buoys the brain until the
tissue has begun to harden and can partially support its own
weight. The pressure is nearly enough equal on all sides to
prevent any noticeable change of form. It is recommended that
the cavities of the brain be filled with the mixture (ccelin-
jected) and if practicable the blood-vessels also injected.
After an immersion of about three days the specimen should
be transferred to equal parts of the foregoing mixture and
seventy per cent. alcohol fora week or more, where on account
of the lesser specific gravity it should rest upon a bed of ab-
sorbent cotton ; it is finally stored in 90% alcohol.

The addition of the zinc chlorid to the solution is to expe-
dite the hardening, to differentiate the tissue, and to insure
a more equable and penetrating action. Osler attributes
the differential effect to the glycerin or some impurity in it.
Experiment has not confirmed his statement. Zinc chlorid
coagulates the blood and renders it much darker than usual.
The highly vascular condition of the cinerea would soon ren-
der it susceptible to the action of this salt, and it would in
general assume a shade relatively much darker than the alba.
The sodium chlorid is supposed to render the zinc more solu-
ble, and to some extent to lessen its causticity. The glycerin
is also useful in this latter respect, but its chief use besides
preservation is to bring the fluid up to the required specific
gravity.

A one-fifth per cent. solution of picric acid in fifty per
cent. alcohol has been used by Professor S. H. Gage with
very successful results upon a human brain. ‘The specimen
was carried up gradually to 95% through the intermediate
grades of alcohol. He has also obtained excellent prepara-
tions of fetal brains by injecting the preservative through a
hypodermic needle into the brain cavities.

‘“Dry’’ preparations are those which may remain perman-
ently exposed to the atmosphere at the ordinary temperature,
without apparent detriment. There are essentially two
methods of preparation, the one consisting of actual dessication
or mummification, in which the specimens remain hard and

Brain Preservation 395

inflexible ; the other involves the infiltration of the tissue by
some hygroscopic substance like glycerin which replaces the
natural fluid by abstracting the requisite amount of moisture
from the air. Such specimens, of course, are not dehydrated
and therefore are not dvy in the same sense as those of the
former class.

A temporary dry preparation of the brain for demonstrative
purposes has been recommended by von Lenhossek”. After
thorough hardening in alcohol, the specimen, when needed
for demonstration, is carefully dried in soft linen and then
coated with a thin layer of celloidin applied with a fine brush.
After five or ten minutes the celloidin dries, and as a thin,
transparent, tough membrane affords great protection and firm-
ness to the preparation. If exposed to the air for more than
two hours the specimen will begin to shrink and should be re-
turned to the alcohol.

Paraffin impregnation of brain tissue for dry preparations was
first employed by Fredericq’. Schwalbe™ in the same year
(1876) adopted Fredericq’s method slightly modified. The brain
is hardened in zine chlorid or alcohol, the membranes are re-
moved and the specimen cut into suitable pieces, impregna-
tion 27 toto does not seem to be advisable. After dehydrating
in strong alcohol, immerse in turpentine until completely sat-
urated, then infiltrate with soft paraffin at a temperature of
60° C. from five to eight days and let cool on a layer of cotton
taking care to avoid deformation. W. C. Krauss" and others
have employed a similar method and recommend it for friable
specimens.

Dr. J. W. Blackburn’s' method consists of allowing the
specimen to harden for about five weeksin Miiller’s fluid, the
pia being removed after a few days immersion. After
thorough dehydration in alcohol it is placed in a saturated
solution of Japan wax (a concrete oil, the product of Rhus suc-
cedenea) in chloroform. When the alcohol has been displaced
the specimen is transferred to a bath of pure melted wax and
kept there at the melting point (42° to 55° C.), until
thoroughly infiltrated. Upon removal the wax drains from
the surface leaving it perfectly smooth. A small proportion
of paraffin will prevent cracking.

396 Pierre A. Fish

Stieda” immerses the brain in an aqueous solution of zinc
chlorid for twenty-four hours, as soon as it becomes firm
enough the pia is removed and the specimen is transferred to
ninety-six per cent. alcohol for two or three weeks, to de-
hydrate, it is then transferred for an equal length of time to
turpentine and finally immersed for two weeks or longer in
the ordinary commercial oil-finish. It is laid on blotting
paper to dry for about eight days, and acquires a dull brown
color on its surface. A shrinkage occurs which he considers
unimportant, about one fourth of the original volume being
lost.

Teichman” has pursued a similar course, the difference being
that the brains were hardened in alcohol and finally impreg-
nated with ‘‘ Damar-harz’’ or ‘‘ Damar-lack.”’

So far as Stieda knows Broca was the first to use nitric acid
for hardening the central nervous system. His formula is as
follows :

The brain is left in this mixture for two days ; the quantity
of the nitric acid is then doubled and after two days more the
specimen is taken out and allowed to dry and harden. ‘There
is considerable shrinkage. A method of ‘‘galvanoplastie’’ de-
vised by M. Oré’ is said to give good and durable specimens.
Duval has proposed a modification of Broca’s method in that
the specimen is finally to be infiltrated with paraffin.

Hyrtl” (1860) saw no special advantage in using salts or
nitric acid combinations, and gave the preference to alcohol ;
the addition of sugar as recommended by Lobstein gives to
the specimen a welcome degree of flexibility. His experi-
ments on dry preparations were not wholly satisfactory ; the
brains of a horse and calf were utilized and after hardening in
sublimate were ‘‘cooked’’ in linseed oil and then allowed to
dry. They kept their shape for a couple of weeks but after
some months the horse brain shrunk to the size of a small
apple and that of the calf to the size of a nut.

Giacomini’ was the first to use glycerin for “‘ dry’’ prepara-
tions ; his specimens have been highly commended for retain-

Brain Preservation 397

ing their volume and color to a remarkable degree. All
glycerin methods are essentially the same in principle and
differ from Giacomini’s chiefly in the manner of hardening
and manipulation. Giacomini prefers a saturated aqueous
solution of zine chlorid for hardening although potassium
bichromate, nitric acid or alcohol will give good results. The
pia is removed after an immersion of twenty-four hours in the
zine chlorid solution, the brain remains in the liquid for two
or three days longer, until it tends toward the bottom of the
vessel, when it should be removed, as a longer stay would
cause it to absorb too much water, it is then transferred to 95
per cent. alcohol where it may remain indefinitely, ten or
twelve days usually being sufficient. The specimen is finally
put into pure glycerin or glycerin containing carbolic acid to
the amount of one per cent., when it has sunk just below the
surface it may be removed and exposed to the air. After a
few days when the surface has become dry, it is varnished
with india rubber or better yet with marine glue varnish di-
luted with a little alcohol. This completes the process.

Dissections should be made previous to the glycerin bath.
Histological detail is also said to be preserved to aremarkable
extent.

Laskowsky’s” method consists of first washing the fresh
specimen in water to remove the blood, it is then placed in the
following mixture ;

‘GIR Se Oe Sie ae 8 A Oe RR fa . 100 parts.
eR COLON ase) sais ose ane sonic uch le Seas 20 parts.
ROR ACIC ACTA ao). c iad sig sunt shea olny eines 2 hes 5 parts.

Kept in a cool place.

The pia is removed and the brain then placed in a saturated
alcoholic solution of zinc chlorid for five or six days, the
bottom of the vessel being covered with cotton.

Transfer for fifteen or twenty days toa mixture consisting of :

Mriveemite ery tres co's cas eee ee a 100 parts.
PUICOUB MIN pont eye iN Ae «, 2O"parts:
Car oOMe reciting. ss l<hstcsveeu te abe 5 parts:
BOraciemendyerr sos 2.0.0). Pa 5 parts.

Let the specimen dry in the air, protected from dust.

398 Pierre A. Fish

Max Flesch® recommends the addition of one part of cor-
rosive sublimate to three thousand parts of glycerin. A hu-
man brain he leaves in water for two days in order to wash
out the blood, it is then placed in alcohol for four weeks; then
for two weeks in equal parts of glycerin and alcohol and
finally four weeks in pure glycerin, to every three thousand
parts of which is added one part of corrosive sublimate (the
sublimate is dissolved in a small quantity of water and alcohol
and then added to the glycerin). Wherever it is necessary the
brain is supported upon a layer of cotton to avoid deformity.

After the drainage of the superfluous glycerin the specimen
is again placed for final storage upon a piece of blotting paper
supported by a layer of cotton and the whole enclosed by a
paste board box with a glass top, to protect from the dust.
The expense is slight as the solutions can be used repeatedly.
The alba and cinerea are said to remain well differentiated.

Struthers” hardens the brain in alcohol after the removal of
the membranes, for ten or fourteen days. It is then put into:

GI CET 6 Shiela) “1 ad ad ay to ieee et gee
CarbolesAcid 5c ime reuelhe telat eay mani manatee

for two or three days. When the superfluous glycerin drains
off, the brain is put under a glass case in order that it may not
take the dust. It is claimed that there is less shrinkage and
more flexibility than in Giacomini’s method.

Richardson” recommends the following formula :

Gly cerita) 02) as ste teeta OO es
Methylatedspirit: .- 17 5.0 arcane oeo'e. c,
Fine chiorid:. 3) 0) i.) io eee 2 grams.

‘* Dissolve the zine chlorid in the spirit and gradually add the
glycerin. In use immerse the structure in the solution and
keep itin until it is fully saturated. Then remove and let
harden,”’ [dry].

As a result of numerous experiments and a careful study of
previous methods, the following process was devised: ‘The
preliminary treatment is as directed on page 393. After dehy-

Brain Preservation 399

dration in repeated. changes of ninety-five per cent. alcohol,
immerse the brain in a mixture of:

PUP DOMENIE Ts le) <a seer ee 3) Darts:
Seto ONN A yea aise tp ee ak | Dares

until it becomes tolerably translucent (one or two weeks)
changing the solution if it becomes cloudy, then transfer to
pure castor oil for a week or two. Allow it to drain on a layer
of cotton covered with absorbent paper until the surface dries
and then paint it over a few times with an alcoholic solution of
bleached shellac. The specimen soon becomes firm and re-
quires no special attention when once it has become dry. This
process differentiates alba and cinerea well. (See Plate).
The brain sections or dissections should be made before im-
mersing in the turpentine-oil mixture. It will be found that
the alba becomes translucent first, the preparation at this par-
ticular stage may then be put into the pure castor oil until
thoroughly penetrated and subsequently drained and shellaced.
The castor oil may be used repeatedly and costs only one-half
as much as glycerin.

Some shrinkage occurs, the dry specimen losing about one-
fourth of its volume after it has left the liquid. It should be
remembered that the brain consists of eighty-eight per cent
of fluid and that the possibilities of evaporation and the re-
placement of this natural liquid by an artificial one as in
dehydration render some shrinkage inevitable. It is not
feasible therefore to harden a brain rapidly without some con-
densation of tissue, the main point is to harden the specimen
without distortion or to have the shrinkage evenly distributed.
Theoretically the shrinkage might be lessened or entirely
obviated if each fluid or mixture into which the brain is
immersed could be kept at the same specific gravity as the
brain itself, and replace equally its normal fluid. ‘This does
not seem to be practicable where dehydration is necessary.
The dry process has given good results on delicate fetal brains,
it seems to strengthen them so that they may be readily
handled, but great care must be taken in transferring them
through the different fluids. If breakage should occur the

400 Pierre A. Fish

parts may be stuck together with mucilage and after shellac-
ing again the specimen will be as durable as ever.

There are objections to both the dry and glycerin methods.
The former renders the specimens too hard and there is per-
haps a little more shinkage; with the latter there is more
flexibility but there is a greasy and disagreeable feel to the
preparations. Experiments are in progress with a view
toward combining the more desirable features of each, by
compounding an emulsion in the following proportions :

Slwcerim .: 9. Vo acte ee a au a oe ee BOOIME RE

Gastor Ot). ayn uk Sahat) oe Vat) ol DUG@Ucames

Gum arabia 0c) ee ele erate. wl SO amie
or,

Gum tragacauth:. |). 0) 7. Spiess) hae 50: aneaes

If well made it does not ‘‘crack’’ and seems to penetrate the
tissues quite well though somewhat slowly. The emulsion
can be used repeatedly by rubbing it up again in a mortar be-
fore putting a new specimen into it. The brain may be shell-
aced as in the previous method.

The writer wishes to acknowledge his obligations to Pro-
fessor Wilder whose kindly interest in this line of work has
rendered practicable many interesting experiments and whose
indefatigable energy in scientific research has been an example
as well as an incentive in the preparation of this paper.
Acknowledgments are also due to Professor H. H.
Donaldson of Chicago University and to Professor S. H.
Gage of Cornell for valuable suggestions.

ITHACA, N. Y.
Avucust, 1893.

‘al

A AAWN

25.

20

REFERENCES.

. BLACKBURN, J. W. British Medical Journal, May 18, 1889. p.

eh i

. British Medical Journal, April, 1892.

. Broca, P. Mémoires sur le cerveau de l’homme. 1888.

. Cyclopzedia of Anatomy and Physiology, III, p. 669.

. DonaLpson. H. H.and Bouton, T. Ll. Amer. Jour. of Psychology,

IV, pp. 224-229.

. FLESCH, Max. Anat. Anzeiger, II, p. 294. Abstr. in Jour. Roy.

Micr. Soc., VIII, 1888, p. 507.

. FREDERICQ. Bull. de l’Acad. roy. de Belg. 2 ser. XL. June,

1876.

. GARNER, R. Jour. Anat. and Physiol., XV, p. 537.
. GIACOMINI. Arch. per le Scienze Mediche. 1878. p. 11.

HyRTL, JOSEPH. Handbuch der Praktischen Zergliederungs-
kunst. Wien, 1860. .

. Krauss, W. C. Buffalo Medical and Surgical Journal. Nov. 1888.

f Ste ae S. L’Embauement et la conservation des sujets.
1886.

. — Neurol. Centralblatt. WI, pp. 341-342.

. LEE, A. B. The Microtomists Vade Mecum. 18go.

. MULLER, J. Arch. f. Anat. 1834. p. 95.

- RICHARDSON, B. W. Wood’s Medical and Surgical Monographs.
III. 1889.

. ROSENBACH, O. Centralbl. f. Nervenheilkunde von Erlenmeyer.

XII Jahrg. 1889. No. 6.

. SCHWALBE. Anat. Anzeiger. I, 1886, p. 322.
. STIEDA, L. Anat. Anzeiger. WI, 1891, p. 450. Also Neurol. Cen-

tralbl. No.5. 1892.
. STRUTHERS. Jour. Anat. and Physiol. XXII. Appendix. p. IX.

. UNNA. Arch. f. Mikr. Anat. XXX, 1887, p. 47.
- VON LENHOSSEK, M. Anat. Anzeiger, II, 1887, pp. 3-17, Also

abstr. in Amer. Nat., XXII, pp. 858-859.

. WHITMAN, C. O. Methods in Microscopical Anatomy and Embry-
ology. 1885.
. WILDER, B.G. Article: Brain, Removal, Preservation and Dis

section of. Ref. H’db’k of the Med. Sciences, VIII, I889, pp. 195-
201.

Supplement. Ref. H’db’k of the Med. Sciences. 1893, pp.
III-I21.

. WILDER AND GAGE. Anatomical Technology.

DESCRIPTION OF PLATE.

All of the figures are at about the natural size of the dry specimens
and were prepared according to the castor oil method.

The transections show the differentiation of the alba and cinerea.

Fig. 1 and 6 are from the sheep, Ovzs aries. Fig. 2 and 5 are from
the dog, Canis familiaris. Fig. 3 is the mesal view of the right hemi-
cerebrum of Macacus rhesus. Fig. 4 is the lateral aspect of the right
hemicerebrum of Macacus cynomolgus.

DRY PREPARATIONS OF THE BRAIN—FISII.

THE GENUS PHYLLOSPADIX.
By WILLIAM RUSSEL DUDLEY.

Phyllospadix belongs toa group of plants—the Sea Grasses,
remarkable in their morphological characters, their habitat,
and the probable antiquity of the types constituting them.
The genera are few in number, variously reckoned from seven
to ten, embracing less than thirty known species, and includ-
ing all the flowering plants whose habitat is wholly marine.
The pollen, moreover, in all but three species, has the extra-
ordinary form of long, colorless, mycelioid filaments, a struct-
‘ure suited no doubt to processes of fertilization which must be
carried on usually under water. On the other hand, the or-
dinary granular pollen, adapted for transference through the
air, is practically universal among other Angiosperms.

Two-thirds of the species mentioned form a section in the
Natural Order Potamogetonacez, the other one-third are
grouped with a related order. The five marine genera in the
first-named order, all with filamentous pollen, are Zostera and
Phyllospadix forming a distinct tribe, Posidonia and the two
nearly related genera Cymodocea and Halodula. Zostera has
two widely distributed and three Australian species, Phyllos-
padix is peculiar to the Pacific coast of North America, known
from San Diego to British Columbia and probably beyond
these limits. Posidonia has one species in the Mediterranean
and one on Australian and Tasmanian shores. Cymodocea
has one species in the Mediterranean, one in the West Indies,
and five in the Indo-Pacific Oceans. Halodula has one species
in the West Indies, and one in the Indo-Pacific region. All
appear to be confined to a few fathoms below low-tide mark.
The small number of forms and their often remarkable isola-
tion suggest a long racial existence, marked by great vicissi-
tudes; and the fact that fossil remains, referable only to above-
named types, are found in the Tertiary and even in the upper

404 William Russel Dudley

Cretaceous of Europe, indeed prove these forms to be of very
ancient origin. Zostera is by far the best known genus and
is apparently one of the oldest types. It is the only genus of
the group which has species at all cosmopolitan in their dis-
tribution. One of these, Zostera marina, frequent in the old
world, extends to the shallow bays and tide-water coves of
Atlantic North America, and is the only sea-grass found in its
waters. ‘The distinguished morphologist, in whose honor this
paper was written, will recall the submarine meadows of Zos-
tera along the New England coast as giving shelter to num-
erous forms of animal life. The wide extension of this species
and Zostera nana, an old-world form, so far as definitely
known, shows Zostera to be the most flexible and the strongest
of the old types believed to exist in the Tertiary seas.

From this strain only one other subsidiary type of generic
importance—Phyllospadix, appears to have sprung and per-
sisted till recent times. This genus and Zostera are charac-
terized by a flattened spadix, closely invested by the spathe,
in which the flowers are entirely concealed until anthesis.
The moncecious spadices and ovoid fruits of Zostera are re-
placed in Phyllospadix by dicecious spathes and cordate-
sagittate fruits. The retinacula, or appendages protecting the
sexual organs, wanting in some Zosteras, small in others, are
strongly developed in Phyllospadix.

Some years ago, while in Berlin, my attention was partic-
ularly called to the genus under consideration, while looking
over with Professor Ascherson the drawings for his mono-
graph of the order in the ‘‘ Pflanzenfamilien.’’ I was then
chiefly struck with the fact that the genus was a nearly mono-
typic one and peculiar in its geographical restriction. When
the plants were first seen growing along the bold shores of
Santa Cruz county, one was most impressed by the remarkable
departure from Zostera in habitat. Like many of the great
Alge, it is either a surf plant living on exposed rocky points,
or grows in coves of rocks and sand, where the strong move-
ment of the waters keeps the long, supple leaves constantly
doubling upon themselves.

As this paper concerns itself with the morphology, anatomy

The Genus Phyllospadix 405

and environment of the genus in relation to its probable ori-
gin, I will dismiss, for the present, the question of the species
with the following remarks : The two species of the California
coast have been collected about Monterey Bay, and somewhat
carefully examined together with dried material collected
along the coast from Oregon to Santa Barbara. ‘They are
closely allied forms, although it will be convenient to refer to
them as distinct species. Phyllospadix Scouleri, described as
early as 1840 by the elder Hooker from Scouler’s specimens
from the Columbia River, inclines to bolder shores, has a
flatter leaf, often but not always a much shorter stem, with
one spathe (occasionally several), and usually larger fruits
than Ph. Torreyi, Watson. ‘The statement that the leaf is
broader does not always hold, and three nerves are present in
both, instead of only in Ph. Scouleri, as is usually stated.
They are more obscure in Ph. Torreyi on account of the
leathery texture of the latter, thrice as thick asin the sister
species. The very doubtful Ph. serrulatus, Rup., I have not
seen, and nothing seems to be known of it beyond the frag-
ment on which Ruprecht based his description.

What follows concerning the morphology and structure of
the genus relates to Ph. Torreyi, reference being made to the
second species by especial mention.

Phyllospadix grows attached to rocks, or to a rocky substra-
tum covered with a few inches of sand, in distinct turfs or flat
tussocks usually, each being from one-fourth to one-half a
meter 1n diameter, and composed of branched, rooting rhizomas
giving rise to the long leaves among which are concealed the
much shorter spathe-bearing stems. It is not often seen extend-
ing more than one or two fathoms beyond low-tide. At very
low water a fringe of plants along the upper margin of the belt
is often left completely exposed, but ordinarily the plants are
not left quite bare. They cling by means of short, firm roots
and the under-surface of the somewhat interwoven rhizomas,
to hard surfaces, somewhat after the manner of the larger
Algee ; and although the stems and leafy branches break away,
the rhizomas seldom loosen their hold except with age.

The rhizoma and the arrangement of its dependent mem-

406 William Russel Dudley

bers appear never to have been described. Benthain and
Hooker, in the Genera Plantarum, describe the rhizoma as
tuberous-lobed. Ascherson uses a similar expression, and
Morong’s recent figure shows a tuberous body at the base of
the stem. This error has come from the examination of her-
barium specimens, where the rhizomas usually appear bro-
ken into knotty masses. There is no suggestion of tuberous
or bulbous formations about any living specimen. The
growth is monopodial, and one can obtain specimens from ten
to twenty-five centimeters in length, the usual thickness being
about one centimeter. Referring to Plate I., B, a remarkable
symmetry will be observed in the arrangement of the lateral
members. Applying the terms ‘‘ node’’ and ‘‘ internode ’’ for
convenience only, it will be noticed that the fourth leaf and
branch (I* b‘,) through the growth of the internode next for-
ward have been separated from the terminal bud, which has
freed itself by pushing forward out of the sheath of the fourth
leaf. ‘The branch does not even in the bud occupy the axil of
this leaf, and at present can be seen supra-axillary, much
separated, and also about to free itself from the sheathing
fourth leaf. The growth of the internode also exposes the
epaulette of eight minute roots (r*) in a double row on the
shoulder of the rhizome, just below the next or fifth leaf, and
on the opposite side from, but above the fourth branch, (b‘).
The number of the roots is either eight or six in each epau-
lette, in all the plants seen, and the older are furnished with
branched rhizoids. ‘Throughout, the protective precautions
will be found remarkable. ‘The earliest sheath (1') envelops
all the younger members of the rootstock forward, 1’, 1° per-
forming successively the same office. In addition to this cu-
mulative sheathing, the thick midrib of each leaf-sheath will
be found directly over the enclosed branch-bud it immedi-
ately protects. As the rhizoma develops, every young lateral
member in the manner above described frees itself from the
mumimy-like wrappings, one by one, and takes its place in the
plant community. It will be observed that the arrangement
of the roots, branch and leaf is alternately reversed in each
succeeding internode, the cartilaginous roots alternating with

The Genus Phyllospadix 407

the branch, affording at once an even support in the sand or
on the rock, and balance in the water, very complete and ef-:
fective as a mechanical arrangement calculated to resist great
strain.

Zostera, accustomed for the most part to protected waters and
more or less muddy bottom, has numerous weak roots in ir-
regularly placed cushions, and the more fragile leaves exhibit
no especially effective means of bud-protection.

The fibro-vascular bundle-traces (C’) show that the leaf-
trace, and the root-trace in the ‘‘internode’’ behind it arise
from nearly the same plane and simultaneously, the leaf and
roots themselves never being far separated when !mature.
The bundle-trace to the branch has a very different origin,
and at no time appears axillary. In the older parts of the
rhizoma there are three fibro-vascular traces (the vascular
system weakly developed), but the lateral ones are not in a
plane with the branches and roots. At each branching of the
central trace, however, toward the leaf or roots the lateral
traces send in to its support tributary horizontal branches.

The leaves, mostly from sterile branches, are numerous,
slender, smooth, coriaceous, dark-green, from one to two and
one-half millimeters in width, oval in cross-section, and
usually from one to two and one-half meters long. They are
provided with sheaths from ten to thirty centimeters or more
in length, opening at the side and ending in short, rounded
stipules. The numerous small nerves of the sheath are re-
solved above into three, which continue through the length of
the long lamina to near its two-lobed extremity. At intervals
there are simple cross-veinlets. The extremities of the
young and still enclosed leaves are beautiful objects, from
the development of the ruffs of ‘‘fin-cells,’’ transparent, of
various forms, and arising from the leaf a little within the
margins (Fig. K). These persist after the leaf is free in the
water. Similar structures are known in species of a few re-
lated genera.

The slender (one to two millimeters in width) flowering
stems, are from lateral branches, and are concealed and pro-
tected by the more distal leaves of the leaders. They are

408 William Russel Dudley

quite leafy at the base, and rise from one-third to two-thirds
of a meter, to the summit of the upper spathes, and by means
of the extension of the leafy tips of leaves, spathes and
spathe-sheathes, are continued to the height of a meter or
more. In the stem are from three to five nodes with sheath-
ing leaves, one or two of the lower leaf-sheaths usually
empty. The upper are occupied by the clusters or branches
of spathes. The uppermost cluster, however, terminates the
stem, and usually has no sheathing leaf corresponding to
those of the nodes proper, its place being taken by the lower
spathe-sheath. The stems of staminate plants are usually
shorter than those of the pistillate; and instead of two or
three spathes in a cluster, there are usually three or four
shorter ones in the staminate plant. ‘The pistillate inflor-
escence is carefully shown in Plate I, A, and apparently this
arrangement is repeated, in both sexes, in all cases. The ar-
rangement of spathes and spathe-sheaths is the same as in
Zostera, except there is no prolongation to the axis of the
branch bearing them. From their beginnings the buds and
the sexual organs are provided with a remarkable system of
shields. Referring to figures A and C' we shall find retina-
cula, spathe, spathe-sheath, successively embracing the mem-
bers within, and the whole, as well as the other branches
above it, enclosed by the strong sheath of the nodal leaf.

As the various sheaths burst because of the expansion of
the growing parts within, the flat, broad, shredded remnant is
seen, characteristic of the older leaves of Phyllospadix.

The spathe proper and its spadix are sessile on a flattened,
common peduncle, two to three centimeters long. Reference
to the figures D and FE will show the flattened staminate
spadix, the oblique arrangement in two rows of the pairs
of sessile, distinct anther-lobes, (each pair a single ‘‘ two-
celled’’ anther), protected by the broadly ovate, somewhat
falcate, obtuse retinacula or appendages; also the young
pistils in two rows on the pistillate spadix, their retinacula
oblong and obtuse.

But we must here state at length several additional facts
which appear never to have been recorded, and correct a few
important errors.

The Genus Phyllospadix 409

In anthesis the staminate retinacula, firm, chartaceous, over-
lapping laminee, lift, then recurve one by one, only as the in-
dividual anthers mature (Fig. D). They push off in this
process the spathe, and neither ever returns to the original
position, as their protective function of course ceases with the
discharge of the pollen. The cells of the outer epidermis of
an appendage at the line of flexure are longer and thinner
than the adjacent ones, and those of the inner epidermis are
shorter and thicker walled. Presumably an increase of cells
takes place among the latter at anthesis.

The stigmas, only, of the young pistils are extruded at ma-
turity (Fig. A). The spathe and retinacula closely invest
them, until by the growth of the fruit and the curvature of
the old spadix (Fig. E) the whole is carried out of the spathe.
But at no time is there a reflexing of the pistillate retinacula,
although Ruprecht’s figures and some descriptive statements
assert the contrary.

An interesting fact developed is the presence on the pis-
tillate spadix, alternating with the pistils, of pairs of rudi-
mentary anther lobes whose lower part is sufficiently de-
veloped to produce even a few pollens, the upper portion re-
maining an undeveloped cellulose point (Fig. G). No pollen
is apparently discharged, however. If these anthers had
been fully developed we should have precisely the arrange-
ment and appearance of the moncecious spadix of Zostera.

In Zostera, apparently the older genus, there is a curved
ridge connecting the twin anther-lobes in their younger
stages. This is believed by Hofmeister and subsequent ob-
servers to be a ‘‘connective,’’ and as each of the two lobes
has the two pollen-sacs or loculi of the ordinary anther-lobe,
the two lobes together form one quadrilocular anther,
which appears on the Zostera spadix alternating with the
single pistil. The rudimentary anthers on the pistillate
spadix of Phyllospadix are connected throughout their whole
existence with exactly such a curved ridge, shown in figure
G. On the staminate spadix, however, this connection is
scarcely traceable, even when the anther is very young, and
when it is mature the connective seems to have disappeared.

410 William Russel Dudley

That these rudiments have a normal origin is seen in G,
(left hand fig.), a drawing from sections of the young pistils
and anthers where the latter appear to be as well-formed at
this stage as the ovaries. The number of anthers on a well-
developed staminate spadix is usually twenty or twenty-two,
(forty to forty-four lobes), the number on the rudimentary
ones on a similar pistillate spadix is about twenty, the pistils
eighteen or twenty, showing that on the staminate spadix an-
thers have not developed in place of pistils ; on the contrary, I
have not been able to find the least trace of a rudimentary
pistil either on the young or the mature staminate spadix.

From this evidence, the derivation of one genus from the
other seems undoubted ; also it would appear that the stami-
nate spadix, and consequently the dicecious condition of the
genus had taken on a very decided character, and had
probably been brought about in recent geologic times, if we
are to judge by the persistence and character of the rudi-
mentary organs.

In structure, the anthers have been described by Bentham
and Hooker and others as ‘“‘like Zostera.’’ ‘The rudimentary
organs with their connective enable us to prove this assertion,
the pair, as in Zostera,* constituting but a single anther.
Sections of Phyllospadix anthers (Fig. J) also show that
each lobe has two pollen-sacs similar in appearance to those
seen in sections of the anther-lobes of our Pacific coast Zos-
tera. In one respect they differ, however. In Zostera the

* A curious confusion in the description of Zostera anthers appears in
all the standard systematic works in England and America, viz., in
Bentham and Hooker, Gray’s Manual, and Watson’s Bot. of Cal. The
‘anther is described as ‘*‘ one’’ and ‘‘ one-celled’’—a manifest contradic-
tion. If the anthers are single, between pistils, then they are not one-
celled. If they are one-celled, then what we have termed anther-lobes
must be considered as two anthers. Eickler in ‘‘ Bluthendiagramme,”’
and Ascherson in ‘‘ Die Pflanzenfamilien,’’ give a lucid and perfectly
correct diagnosis of the anther. Bentham and Hooker say of Phyllo-
spadix also, ‘‘anthera .... 1-locularis,’’ which may have led Mr.
Morong, even so late as the current year (1893), into the statement,
(Naiadaceze of the U. S.), that Phyllospadix has ‘‘ numerous sessile
stamens in two rows. . . I-celled.”’

The Genus Phyllospadix 4It

wall between the sacs disappears at the dehiscence of the
lobe, after the usual mode in anther-lobes in quadrilocular
anthers, and leaves the lobe “‘1-celled,’’ as the phrase is.
But in all the Phyllospadix examined, the dividing cellulose
wall, after the discharge of the pollen, is left as a firm mem-
brane (Fig. D, a). This gives somewhat greater protection
to the pollen, no doubt, than the more fragile wall found in
Zostera.

While at the Hopkins Seaside Laboratory, I was enabled to
investigate the anther dehiscence and the probable mode of
pollination. This was done by means of the sea-water tanks,
as well as observations along the shores of Monterey Bay.
The alternating low-tides on this coast are known as the
“large”? and ‘‘small’’. The ‘‘large’’ tides at the change of
the moon often leave Phyllospadix uncovered; but at such
times these tides do not occur when the sun is much above the
horizon, so there is little chance of leaves or flowers being
destroyed, as they would be if exposed to the air and sunlight
at the same time. The staminate plants are much less num-
erous than the pistillate. In the localities most favorable for
the Ph. Torreyi flowers, the proportion of staminate to pistil-
late was about one to twelve. In more exposed situations
staminate plants were much rarer, and on much exposed
shores pistils of Ph. Scouleri* often fail to be fertilized, —per-
haps not wholly on account of the scarcity of the staminate
plant, for the violence of the surf no doubt disperses and de-
stroys the pollen toa greater extent than in quieter places.
The staminate plants, according to my experience, occur more
inshore ; the pistillate plants are all about them, extending
also into deeper water.

After the anthers with partially reflexed retinacula have
been exposed to the air fora time in the low early-morning
tide, or have remained in the comparatively quiet shallow
slack-water of the ebb, they will open more readily, with the

*Hooker’s erroneous figure showing an ovoid pistil (Flora Bor.
Amer. IT, t. 186.) may have been based on a specimen with unfertilized
withered ovaries. His ‘‘capitate stigma” is the tip of astyle from which
the stigmas have fallen.

412 William Russel Dudley

accession and quickened movement of the earlier waves of the
flood. ‘The anther opens near its lower obtuse end, rips up-
ward along the depressed median line with a quick movement,
and exposes the numerous pollen filaments, lying parallel and
obliquely placed in each pollen-sac. The masses are white,
silky, and appear somewhat spirally twisted. The slow ad-
vance and recession and the sudden lashing of the swell carry
the long locks of sea-grass with them, throwing the spadices
back and forth, and dragging them ‘roughly on one another
and on the leaves.

The pollens average 1 millimeter in length by .004 to .005
of a millimeter in breadth. They are slightly flattened and
broadened at the extremity (Fig. D., pn.), andsome are enlarged
toward the middle. Each pollen filament when first exposed is
protected by a layer of air, andacluster of them loosened from
the pollen sac springs immediately to the surface of the water,
while the filaments repel one another sufficiently to form at once
a silvery arachnoid film, perhaps a centimeter across. These
are never abundant, but they float hither and thither with the
water, and among the doubling and swinging pistillate plants.
At the lowest stages of the tide the films of pollen could easily
be thrown upon the half-exposed pistillate spadices, and would
adhere to the protruded stigmas, as they were observed to do
in the aquarium. Unquestionably this is one mode of pollin-
ation.

When the pollen has been exposed for hours in the open
sac, it does not necessarily rise to the surface but floats in the
water where it can be more readily carried to the usually
submerged stigmas. Clavand, (Actes d. 1. S. Linn. d. Bor-
deaux, T. II, 1878,) describes this as the mode of transference
in Zostera marina, and mentions no others; but the young
pollens of the Pacific coast Zostera spring to the surface,
exactly as do those of Phyllospadix. I have examined imi-
croscopically both the floating and the submerged poilens of
Phyllospadix, taken in the conditions above described, and
found in both the natural streaming of the protoplasm. Both
would presumably be capable of effecting impregnation at the
time. ‘The protoplasm was observed streaming ina filament

The Genus Phyllospadix 413

taken from an anther three days open, and they may possibly
live a much longer time in the open sea.

The stigmas are described as capillary by most authors ex-
cepting Ascherson. They are ovate lanceolate, acuminate,
thin, irregularly lobed and laciniate.

The nucleus of the single, orthotropous, pendulous seed,
enclosed in a strong double testa, is carinate dorsally, some-
what compressed, and presents, like all the forms related to it,
a largely developed hypocotyl with no surrounding endos-
perm. The hypocotyl has two lateral fleshy lobes folded
toward the cotyledon (Fig. H). The narrow cotyledon, two
millimeters long, is tubular and two-lipped, the posterior lip
two-lobed and shorter. Enveloped by the cotyledon are two
to four alternately shorter flat laminze, obcordate or roundish,
the first leaves of the plumule (H, lower fig.).

In various places we have referred to the bearing of peculiar
morphological features upon the generic characters of Phyl-
lospadix. We now turn to the anatomy of the vegetative
organs.

The rhizoma has marked provisions for clinging to a hard
substratum, but in itself is brittle and weak. The leaves and
stems are correspondingly strong and flexible, the root firm
and resistant.

The rhizoma is almost wholly a mass of parenchyma. Of
the three bundle-traces the middle one only shows a few poorly
developed annular, reticulated or dotted vessels, some weak
libriform cells, and no strong wood-fibres. Sclerenchyma fibres
arewholly wanting. Indeed, the only strengthening tissue in
the rhizoma is collenchyma-like cells appearing in a few
rows in the cortex.

Turning to the figures of the root-sections (R), it will be
seen that the firmness in the root is due to the broad sheath
of epidermal and hypodermal cells with remarkably thickened
walls, the parenchyma of the middle region remaining thin-
walled.

Figure L, shows a transection of the leaf of Ph. Torreyi
near the epidermis; and M, (lower fig.) transections of a por-

A414 William Russel Dudley

tion of the stem of Ph. Scouleri. The stem and the leaf we
have found bear the brunt of the surf; and underneath the
thick chlorophyllous epidermis, destitute of stomates, both
members show large areas of strong sclerenchyma fibres (sc.),
each fibre several millimeters long and of surprising strength.
In the flat leaf of Ph. Scouleri, the entire margin of the leaf
beneath the epidermis is a steely strand of sclerenchyma, and
the remaining tissues are well armored with it. Schwenden-
er’s demonstration in ‘‘ Das Mechanische Princip,’’ that the
sclerenchyma is the prime factor in the strengthening appara-
tus of a plant could find no better illustration. For after the
old leaves are beaten to pieces by the tremendous surf these
fibres long remain at the base. Bold shore specimens can be
recognized in herbaria from the numerous bristle-like strands
of sclerenchyma remaining at the base of the stems.

The longi- and transections under M, of a stem fibro-vascular
bundle, illustrates its simple and feeble structure.

Zostera leaves, even those of our large coast species, show
large lacunze and no sclerenchyma fibres whatever, in the
specimens examined. ‘The stems are relatively no stronger.
These Monterey Bay Zosteras, although in open water are
subjected to no such impact as the plants growing in the surf.
It is only in the rhizoma, where there are scattered strands of
sclerenchyma, that we find a member stronger than in Phyl-
lospadix, the roots being without strengthening elements, as
Sauvaugeau has demonstrated those of Zostera marina to be.

Aside from correcting certain errors this structural study has
brought out two salient facts: First, the genus Phyllospadix,
not yet found fossil, so far as we know, is probably an off-
shoot and apparently a recent one, from the much older genus.
The presence of the now quite useless but still well-marked
rudimentary male organs on the pistillate spadix, which pre-
sent us with an inflorescence identical in plan with that of
Zostera, is offered as evidence of this; while the separation of
the sexes, on male and female plants, indicates a differentia-
tion in advance of the original moncecious arrangement still
adhered to in the last-named genus, and shows the vigor of

The Genus Phyllospadix 415

the later type. Second, the conditions in which the ancestors
of Phyllospadix, on this coast, found themselves, have forced,
in the growth of the genus, the development of an unusually
strong stereome, or system of strengthening cells in stem and
leaf, to which Zostera has no tissue which will bear any com-
parison, anda symmetrically balanced rhizoma with a remark-
able system of shields and sheathing members, designed to
protect the buds and young reproductive organs.

In the morphology and anatomy of a plant, I believe we
may find at least a partial record of the influences of past
environment in the struggle of the organism, not only for
existence, but for upward development ;—z. ¢., for a mode of
living which will make the best use of the resources at its
command. In its present environment, if likely to have been
long continued, we may find still further explanation and cor-
roboration of the structural evidence. In looking for the
causes which lead to the evolution of a new genus we may
profitably consider a similar line of evidence, adding the testi-
mony to be derived from geographical changes and geological
records.

We have already sufficiently explained the present habitat
of Phyllospadix, on stony and rocky shores, and connected its
peculiar structure with the supposed effort on the part of the
organism to meet the conditions (for a plant) of an unusually
stirring existence. But why a brauch of the shallow-water
Zosteras should have ventured on this bold career, and what
the conditions really were during its earlier years, cannot per-
haps be more than imperfectly answered, in the present state
of our knowledge.

Referring again to the distribution of living sea-grasses,
and leaving out of account the two Zosteras of wide distribu-
tion, and the few doubtful species and stations, we find there
are certain geographical centers of development. And we
may suppose these regions to have preserved something in
their conditions, at least not unfavorable to the continuance,
and even favorable to the further development of the old ge-
ologic types. They are grouped as follows :

416 William Russel Dudley

Australian shores, (inc. 1 Malayan form), 15 species.

[Eight of the above extend westwardly along the
Indian Ocean shores to the Red Sea and down the
E. African coast region, where appears one addi-
tional species ]

The Antilles, (including Key West),.. . 5 species.
Paciine; North Amencayia ii ik) i othe haan) see
‘Phe Mediterranea 0.64) G26) ales 2 Mah Dae

Not attempting here to account for the discontinuousness of
these areas, we call attention to the fact that the principal cen-
ter named,—Australia,—is a region where an unusually large
number of the Eocene types of land plants are found living,
preserved no doubt through absence of violent change in con-
ditions. Similarly a conspicuous number of Miocene and
Pleiocene forms are represented in the present Western North
America Flora. ‘These facts in a broad way may have their
significance ; and, as bearing upon the question, we may be
allowed to refer,—in connection with the present uniform
aerial temperature of California, accompanied by a surface ma-
rine temperature which does not vary 10° in the year at the
Golden Gate,t—to the universally accepted belief that a uni-
form sub-tropical or warm, temperate climate existed around
the whole North Temperate and a portion of the Arctic zones
through long periods of the Tertiary, especially of the
Eocene and the Miocene, times contemporary with supposed
geologic remains of the early Zosteree.

But while the old races have been continued on this coast,
there have been causes at work which have brought about the
vigorous and remarkable divergence seen in the varying forms
of our genus and in the robust open-water Zostera of the Pa-
cific coast. This coast is geologically new. Dana asserts that
the Sierras were lifted in the middle of the Mesozoic, preceding
the Cretaceous, experiencing great subsequent elevation ; also
that the coast ranges date their emergence from various peri-

* This table is constructed from stations vouched for in Ascherson’s
various papers, and slightly modified by later information,

+ According to Professor Davidson’s observations on marine tempera-
tures, 1874 to 1883.

The Genus Phyllospadix 417

ods in the Tertiary. Distinguished later authorities maintain
that much of the coast range region is of recent appearance,
and that it has undergone great vertical oscillations during re-
cent times. The remarkably bold shore of California may be
due to the above phase of its geological history. Ten miles
off the coast the ocean shows an average depth of too fathoms.
But from the brink of this narrow submarine terrace, the bot-
tom rapidly descends to 2,000 fathoms or more, the 1,000 fath-
oms line being on the average only 50 miles off shore. Sub-
marine valleys and cafions of great depth, testifying to some
great subsidence, often cut through the usual terrace-barriers,
into the very shore line itself; such is the case at Monterey
Bay. The bottom temperature 1,000 fathoms off the coast is
35° Fahr., or but little above freezing. The winter surface
temperature at the Golden Gate is about 50°, the summer
temperature less than 60°. In the most sheltered parts of
Monterey Bay, near Monterey, the summer temperature is
about 60°, while on the more exposed shores it has been found
at times to be below 50°.

There is no shallow, shelving sea, as along the old and
long worn Atlantic slope of the United states, and few long
bays or shallow estuaries and sounds, whose temperature is
greatly elevated during hot summers or depressed during cold
winters, and which easily mingle their waters with the open
ocean. On the contrary, on a coast rapidly descending to
great and cold depths washed by a current from the north,
are flung with great force waters of an even but low tempera-
ture, lower still, perhaps, in the vicinity of the submarine
valleys. These beat upon the coast and upon the littoral
plants with great force. Not alone in the furious storms of
the rainy season is the whole coast-line subjected to their
powerful action,—even during the long, stormless summers,
the breakers are undoubtedly greater in size and the move-
ment of the water everywhere stronger than on the Atlantic
coast in similar weather.

In these conditions the marine plants of the eastern Pacific
seem to revel. Gigantic fucoids, robust red-algze, strong
pliant Zosterze, all attain a completer physical development,

418 William Russel Dudley

perhaps, than in any other waters. Possessing the favoring
influence of annual uniformity, presumably for an enormous
number of years, the apparent rigors of the sea not improba-
bly have acted as a stimulus to the races strong enough to
enter its theatre of action. Not improbably the plastic or-
ganism of Phyllospadix, subject to forces long continued,
inflexible, and dynamically great, has not only developed a
structural system so resistant and perfect as to welcome these
remarkable conditions, but, like the builders of the coral reef,
it can no longer thrive except in the surf or within the influ-
ence of the titanic movement of the open ocean.

I am told that the marine deposits in the coast ranges have
not been sufficiently studied to enable specialists to outline
clearly the conditions prevailing on the east Pacific shores
through the Tertiary and the Quaternary. No question like
the present one can approach a settlement until the facts ob-
tainable from geological sources are recorded.

On the other hand, it can safely be said that the biological
evidence is likely to favor the hypothesis of a very long period
of uniformity in temperature and in the character of the
ocean shores and currents, if not in the shore lines, along the
whole California coast. It is impossible at present to indicate
-its duration, but it may well have existed from early in the
Quaternary, perhaps even from the confines of the Tertiary,
down to present times.

Pato ALTO, CAL.,
Sept., 1893.

EXPLANATION OF PLATES.

PHYLLOSPADIX, PLATE I.

A :—Stem from pistillate plant (Ph. Torreyi), X %. 4r—Z, bases of radi-
cal leaves ; /, cauline leaf with empty sheath ; /', 72, first and sec-
ond leaves with axillary spadices; the old leaf-sheaths are spread
open. I and II, the first and second flowering clusters, with inter-
node and subtending leaf. III, third flowering cluster, terminating
the stem, with no subtending leaf, its earliest spathe on the same
side as the earliest in IT, thereby securing in the bud, the protection
of /?. sh', spathe-sheath enclosing sf', the lower spathe and spa-
dix. sh, second spathe-sheath, enclosing sf”, the second spathe
and spadix.

B :—Rhizoma, (natural size). +. Z. b., roots, leaf, and branch, numbered
through four successive ‘‘internodes.’? The oldest set of roots
has rhizoids with adhering sand.

C' :—Diagram ; transection of a pistillate stem, in the bud; lettered as
in A. sx, spadix.

C* :—Diagram ; longisection of rhizoma, in the bud ; lettered as in B.

D :—(1) Staminate spadix, at anthesis, (natural size). rz, retinacula or
appendages ; sf, spathe ; a, anther-lobes.
(2) An open anther-lobe, x 3, showing the median membrane.
(3) A few pollens, arranged as seen in pollen-sac.
(4) Apices of three pollens (at right), X 700.

E :—(1) Pistillate spadix (Ph. Scouleri), mature, (natural size). sf,
spathe ; sx, spadix; 7, remains of spathe-sheath, remains of a leaf
seen below. The retinacula, 7m, partly conceal the mature fruits,

(2) Above, /7, a single fruit (Ph. Scouleri), front view, x 2.
(3) Same in section, (at the left), showing the point of attach-
ment, and the pendulous seed.

F :—Young pistil (Ph. Torreyi), with stigmas, X 3.

418 William Russel Dudley

perhaps, than in any other waters. Possessing the favoring
influence of annual uniformity, presumably for an enormous
number of years, the apparent rigors of the sea not improba-
bly have acted asa stimulus to the races strong enough to
enter its theatre of action. Not improbably the plastic or-
ganism of Phyllospadix, subject to forces long continued,
inflexible, and dynamically great, has not only developed a
structural system so resistant and perfect as to welcome these
remarkable conditions, but, like the builders of the coral reef,
it can no longer thrive except in the surf or within the influ-
ence of the titanic movement of the open ocean.

I am told that the marine deposits in the coast ranges have
not been sufficiently studied to enable specialists to outline
clearly the conditions prevailing on the east Pacific shores
through the Tertiary and the Quaternary. No question like
the present one can approach a settlement until the facts ob-
tainable from geological sources are recorded.

On the other hand, it can safely be said that the biological
evidence is likely to favor the hypothesis of a very long period
of uniformity in temperature and in the character of the
ocean shores and currents, if not in the shore lines, along the
whole California coast. It is impossible at present to indicate
“its duration, but it may well have existed from early in the
Quaternary, perhaps even from the confines of the Tertiary,
down to present times.

PaLo ALTO, CAL,.,
Sept., 1893.

CORRECTIONS,
p. 412, read *Clavaud.”’
p. 418, (29th line), read “collenchyma-like, the cells,’’
p. 414, (17th line), read ‘‘illustrate.’’

6e 74 ~ ‘
(26th line), read ‘“Sauvagean.”’

In the ‘‘Explanation of Plates’’, under Plate 1, D, Plate 11, .

(Gomise L. M. and R., divide the figures indicating magnification

by 2.

EXPLANATION OF PLATES.

PHYLLOSPADIX, PLATE I.

A :—Stem from pistillate plant (Ph. Torreyi), X %. wr—Zl, bases of radi-

cal leaves ; /°, cauline leaf with empty sheath ; /', 7?, first and sec-
ond leaves with axillary spadices; the old leaf-sheaths are spread
open. Iand II, the first and second flowering clusters, with inter-
node and subtending leaf. III, third flowering cluster, terminating
the stem, with no subtending leaf, its earliest spathe on the same
side as the earliest in II, thereby securing in the bud, the protection
of 72. sh', spathe-sheath enclosing sf', the lower spathe and spa-
dix. sh?, second spathe-sheath, enclosing sp*, the second spathe
and spadix.

B :—Rhizoma, (natural size). ». /. 6., roots, leaf, and branch, numbered

(el

G

through four successive ‘‘internodes.’’ The oldest set of roots
has rhizoids with adhering sand.

:—Diagram ; transection of a pistillate stem, in the bud; lettered as
in A. sx, spadix.

?:—Diagram ; longisection of rhizoma, in the bud ; lettered as in B.

:—(1) Staminate spadix, at anthesis, (natural size). x7, retinacula or

appendages ; sf, spathe; a, anther-lobes.
(2) An open anther-lobe, X 3, showing the median membrane.
(3) A few pollens, arranged as seen in pollen-sac.
(4) Apices of three pollens (at right), X 700.

:—(1) Pistillate spadix (Ph. Scouleri), mature, (natural size). sf,

spathe ; sx, spadix ; /, remains of spathe-sheath, remains of a leaf
seen below. The retinacula, 77, partly conceal the mature fruits.
(2) Above, /7, a single fruit (Ph. Scouleri), front view, X 2.
(3) Same in section, (at the left), showing the point of attach-
ment, and the pendulous seed.

:—Young pistil (Ph. Torreyi), with stigmas, X 3.

PHYLLOSPADIX, PLATE II.

:—The rudimentary male organs (Ph. Torreyi).

(1) On the right, spadix, sa, with one partly mature pistil, circu-
lar scars where two have been removed, and above, several small
ovaries, ov., each with retinaculum, 77. Pairs of rudimentary an-
ther-lobes (joined by the curved connective), alternate with pistils,
X 3:

(2) On the left, a section of very young pistillate spadix, X 120;
ov., ovary; @, anther lobes; vz, retinacula. The elevation under
the anther-lobes is the connective ridge.

420 William Russel Dudley

H :—(1)Embryo of mature seed (Ph. Scouleri), x 5.
(2) The same in longisection ; Ayp., winged hypocotyl; cof., cot-
yledon, inside the first leaves of young plant.

J :—Diagram ; transection of young anthers on staminate spadix (Ph.
Torreyi), showing wall between pollen sacs.

K :—‘‘ Fin-cells’’ near the margin and tip of a very young leaf, X 120.

I,:—Transection of leaf (Ph. Torreyi), showing epidermis; areas of
sclerenchyma cells, sc, and parenchyma, X 600.
M :—Stem (Ph. Torreyi), X 600.

(1) f-v-6, fibro vascular bundle in transection, surrounded by an
endodermis.

(2) Longisection of same, showing annular spiral vessels, soft
bast, and parenchyma.

(3) Below, a transection of stem near the epidermis, the large
areas of sclerenchyma, Sc.

(4) Single sclerenchyma fibre, sc., surface view.

R :—Transection of root (Ph. Torreyi), near epidermis, ef; sheath of
strong, thick-walled hypodermal cells below, X 600.

1D OJ DEL a se-

PAVE, Ts

DUDLEY. leICANIND, Wl,

ORME NS

‘LSIN JIWVS SHL WOYS SASYdNVT SYV1 JO UlVd

DVS SHS

dW Id

THE LAKE AND BROOK LAMPREYS OF NEW
YORK, ESPECIALLY THOSE OF CAYUGA AND
SENECA LAKES.

By SIMON HENRY GAGE.

If one glances at a topographical map of the State of New
York, there will be seen in the western half a remarkable
series of long narrow lakes, with a general north and south
direction. These lakes occupy a basin between Lake Ontario
on the north and a ridge that separates this basin from the
Mohawk River on the south-east, and the Susquehanna ‘River
and its tributaries on the south. This elevation _ bor-
dering the lake basin on the east, south and west, and forming
nearly a semicircle, is drained to the north into the lakes, and
into the Susquehanna and Mohawk Rivers onthesouth. The
area of elevation draining into the Mohawk, and thence to
the Hudson River is, however, comparatively slight.

The central and largest of these lakes is Cayuga (PI. 2),
flanked on the west by Seneca, next in size, then come Keuka,
or Crooked, and Canandaigua Lakes. Ontheeast are, in order,
Owasco, Skaneateles, Onondaga and Oneida Lakes. In ad-
dition to these are numerous small lakes or ponds scattered
among the large ones. A further study of the map will show
that all of these lakes have important tributaries especially at
the head. ‘The outlet either flows into one of the larger lakes
or directly into a common outlet. The final destination of all
the superfluous water is Lake Ontario, through the Oswego
River ; and thence through the St. Lawrence River it reaches
the Atlantic Ocean, 700 to 800 miles to the eastward. With
the other great lakes the connection is by the Niagara River,
the falls forming, at the present time, an impassible barrier
against the passage of fishes from Lake Ontario to the other
great lakes.

422 Simon Henry Gage

From these, the present connections, and from the possible
connections with the Susquehanna and Hudson rivers at an
earlier date, it is to be expected that the aquatic fauna of
Cayuga and the other inland lakes would be rich and varied.

By assiduous personal study and observation and the wise
direction of students, Professor Wilder has shown that in the
Cayuga Lake basin there are 21 families, including 4o genera
and 59 species representing the group of fishes.

A further study of the outlets of these lakes, to Lake On-
tario and thence to the ocean, reveals the fact that they are
long and tortuous, and besides possess many rapids and
shallows. ‘These conditions have probably obtained in recent
geological time, a time sufficiently great to lead one to expect
that the lake forms, especially those that had ceased to be
migratory, would have received acertain stamp or impress
from the special and somewhat isolated environment. Further-
more, migratory or anadromous forms, in bodies of water like
these, where they are surrounded by plentiful food, might grad-
ually become less migratory and as the difficulties of reaching the
ocean were increased by changes in the character of the out-
let or the gradual recession of the ocean, they might finally
remain permanently in the fresh inland waters, and like the
other permanent inhabitants be modified by the special en-
vironment.

The more this lake fauna is studied the clearer does the
local coloring, so to speak, appear. Among the lampreys,
the subject of this paper, there appears not only the local im-
press but almost positive evidence that forms, at one time
naturally passing their adult life in the ocean, have become
accustomed to remain permanently in fresh water with corres-
ponding changes in the more impressionable or less important
parts. I say more impressionable, for it is one of the fruits of
modern research, in the light of evolution, that the most
fundamental organic structures, having to do with the mere
existence of an organism without regard to its upward pro-
gress, are more persistent and less changeable than less
ancient and less important organs, that is, less important from
the mere existence standpoint.

The Lake and Brook Lampreys of New York 423

Problems having a philosophical bearing have always been
the most fascinating to the natural philosopher as well as to
the metaphysician. In the study of living organisms this has
been especially true since the doctrine of evolution has so
profoundly influenced thinking men. Naturally therefore,
Professor Wilder, who came to his professorship in Cornell
University—which itself was making a leap in educational
evolution—during the time when evolution and various col-
lateral hypotheses were in the fiercest conflict with all previous
doctrines, theological and otherwise—naturally Professor
Wilder turned with especial interest to the study of the Cayuga
Lake fauna which promised information concerning the effect
of local environment, and change from preceding conditions.
Naturally also he turned with especial interest to the lamprey,
the lowest representative of the vertebrates found in the lake
fauna.

This interest was transmitted to his pupils, and since 1875
the writer of this article has lost no opportunity of studying the
lampreys at all stages of life, and this study has been devoted
to the living animals rather than to the dead organisms, al-
though the understanding of their activities and physiological
functions has been constantly clarified by experiment and an-
atomical study.

Characterized zoologically the lampreys (Petromyzontide)
are fish like vertebrates, with an eel- or snake-like form and
a metamorphosis, comparable to that of frogs andtoads. The
skeleton is wholly cartilaginous and the notochord persistent.
Neither pectoral nor pelvic limbs nor their arches are present
although the dorsal and caudal fins are well developed. The
branchize are extended, and open by seven independent
openings on each side, and in the adult the gills are pouched
(whence the name Marsipobranchii sometimes used). The
nasal sac is single and blind and opens to the exterior by a
raised papilla on the dorsimeson just cephalad of the median,
or pineal, eye and of the paired eyes. Apparently no jaws
are present and the mouth in the adult is suctorial and armed
with horny teeth; but the rudiments of jaws have been shown
by Huxley and others to exist. The tongue is a piston-like
rasp in the adult, absent or rudimentary in the larva.

424 Simon Henry Gage

According to all zoologists the lampreys (Petromyzontidz)
are very low in the zoological scale, and according to many
they are degraded forms. ‘They are found in the temperate
regions of both the northern and southern hemispheres ; and
all, so far as investigated, lay their eggs in fresh water and
pass their larval life there. Some pass their entire life in fresh
water while others go down to the sea, but all finally, on the
attainment of sexual maturity, once more ascend the streams
to their birth-place where the eggs for a new generation are
deposited, thus completing the life cycle.

Both the lake and the brook lamprey agree entirely with
the designation for the Petromyzontidae as given above, and
besides the lake lamprey agrees with the characters given for
the genus Petromyzon, viz.: The supraoral lamina, or maxil-
lary tooth-plate, is contracted and with two cusps placed
close together ; infraoral lamina or maxillary tooth-plate with
six to nine cusps. The discal teeth are in concentric series ;
those on each side of the mouth are bicuspid. (PI VI).

With reference to the specific relationship of the large lake
lamprey there has been considerable diversity of opinion.
Up to the year 1875, the University had only secured small
lampreys caught on fish, none of them exceeding 15 to 20
centimeters. The coloration of these lampreys was white on
the ventral half and nearly uniformly black, or bluish black
along the dorsal half of the body. In the spring of 1875,
however, there was obtained from Cascadilla Creek, near the
University, a specimen nearly twice as large as the ones
usually obtained and with a strikingly different general ap-
pearance, due in part to the greater size and more variegated
coloration, but mostly to a large rope-like ridge extending
along the back from the gills to the dorsal fin. ‘The two dor-
sal fins were continuous, simply having a depression between
them. ‘The specimen was photographed when fresh and is re-
produced in Pl. III, fig. 5. The general appearance, so
strikingly unlike either the small lake lampreys previously
obtained or the specimens of true sea lampreys in the museum,
seemed to indicate that, responding to its special lacustrine
environment this lamprey had assumed characters which

The Lake and Brook Lampreys of New York 425

might be considered generic or at least specific ; and Professor
Wilder suggested to his special class, before which the speci-
men was brought for study and comparison, that if the peculi-
arities noted in this first specimen were found constant and
characteristic of the lake lamprey one might consider it a dis-
tinct species at least and give it the specific designation of
Petromyzon dorsatus, from the dorsal ridge. But believing
that the admonition to ‘‘ prove all things and hold fast that
which is good’’ should be followed in science as well as in
philosophy, publication was reserved until other specimens
could be obtained to show whether the first was typical ora
mere sport or transient variation from the truly typical form.

It fell to the writer, then student assistant to Professor
Wilder, to prosecute the search for other examples of the lake
lamprey and to aid in the final solution of its life history and
systematic relationship, the work being constantly forwarded
by the advice and encouragement of Professor Wilder, as well
as by the freest use of his personal notes and drawings.

In prosecuting the investigation almost no aid was obtained
from the lake fishermen. All they knew about the lampreys
was that they were sometimes caught clinging to other fishes.
One man, however, living near the inlet, brought to the labor-
atory six larve and stated how they were obtained. He also
said that the large ones went up the inlet in the early spring.
By diligent inquiry of people living near the inlet, information
was obtained so that in the spring of 1876 the explorations of
the inlet were successful and the adult ones were found spawn-
ing, and the larvee were found in the sand banks along the
edges of the stream. Of theseven large lake lampreys caught,
five possessed the dorsal ridge so characteristic of the first one
obtained. Upon dissection it was found that the ridged ones
were males and those without the ridge feinales, so that from
this time on it was exceedingly easy to determine the sexes in
fresh specimens by this feature alone. Alcoholic specimens
which had been caught in the breeding season were far less
easily separated into the two sexes by this sign since the body
was badly shrunken in alcohol, and the females so preserved
often appeared to have nearly as large aridge asthe males. In

426 Simon Fenry Gage

1878-1879 specimens were submitted to Prof. D. S. Jordan,
who designated the lake lamprey as Pelromyzon nigricans of
Leseur in the synopsis of the fishes of North America (82),
remarking : ‘‘It is possibly only a variety of P. marinus.’’

During the college year, 1885-86, S. EK. Meek, one of Pro-
fessor Jordan’s students, as fellow in zoology in Cornell Uni-
versity, made a special study of the fishes of the Cayuga Lake
basin ; and from the interest already aroused in the lampreys
of the lake, he joined the writer, during the spring of 1886, in
a critical and extended examination of the lake lampreys.
Nearly 800 specimens were studied, especially as to external
sexual characters and specific relationships. In a joint com-
munication before the American Association for the Advance-
ment of Science (Gage and Meek, ’86) the following points
were presented: (a), ‘‘ The determination of the specific
identity of the large Cayuga Lake lamprey and the sea lam-
prey ; (b), The determination of the constant presence of a
dorsal fold or ridge in the males and of a ventral fin-like fold
in the females of [the Cayuga Lake] Petromyzon marinus, at
the breeding season.”’

Jordan and Fordice (’85), in ‘‘a review of the North Ameri-
can species of Petromyzontide,’’ remark concerning the
Cayuga Lake lamprey. ‘‘ We have examined marine ex-
amples of this species [P. marinus, |] and also numerous speci-
mens in all stages of growth from the larva to the adult form,
collected by Dr. Burt G. Wilder, in Cayuga Lake, at Ithaca,
N. Y. Among these are types of Petromyzon dorsatus Wilder,
which seems to be merely a land-locked form, not permanently
distinct from P. marinus. ‘The characters assumed to dis-
tinguish this form from the true marinus are, however, more
or less inconstant and not of specific value.”’

Even after the extended study of the 800 specimens men-
tioned above, there still remained to be settled the question
whether or not the external sexual characters of the dorsal
ridge in the male and the anal fin-like structure in the female
were constant throughout the year or merely seasonal char-
acters comparable to so many others known in the animal
world. ‘here was also the query whether the American,

The Lake and Brook Lampreys of New York 427

true, anadromous sea lamprey developed the peculiarities
found in the lake lampreys at the spawning season, and ac-
cording to Seeley (’86) also present in the European marine
lamprey during the breeding season.* Until these questions
could be satisfactorily answered there would remain doubt as
to the really constant peculiarities developed in the lake form.
During the winters of 1875 and 1877 large lake lampreys were
obtained of both sexes, and concerning them the notes either
Say ‘‘no ridge’ or ‘‘ ridge very low and broad,”’ so that addi-
tional information must besought. In the autumn and winter
of 1886-87 great inducements were offered to the lake fisher-
men to obtain large lampreys. During that winter and since
then throughout the year, large specimens were obtained and
brought to the University. All of these large specimens
looked alike. There was no dorsal ridge in any of them nor
was there an anal fin or projecting urogenital papilla in any
of them, and the two dorsals were well separated in all (PI.
III, fig. 6). It was only on dissection that the sexes could be
distinguished. Thus it was definitely determined during the
autumn and winter of 1886-87, that it was only during the
spawning season that the special external sexual characters
appeared in the lake lamprey.

In answer to the second query concerning like seasonal pe-
culiarities in the true marine lamprey : alcoholic specimens
obtained at various seasons were examined, but as stated
above, whether or not a ridge was present during life is not
easy to determine from alcoholic specimens. So that while
ridges appeared on some of them, it was found by dissection that
the animals were in some cases males, but quite as often females.
Uncertainty must therefore continue untila considerable num-
ber of fresh specimens could be examined. ‘This was made
possible by the intelligent aid given by Mr. Thomas S.
Holmes, of Lawrence, Mass., who sent specimens of the marine
lamprey which were running up the Merrimac River to spawn.
The specimens were usually sent in the early or middle part

* During the month of August, 1889, the writer saw in the aquarium of
the Trocadaro in Paris several large marine lampreys, some of which pos-
sessed very prominent dorsal ridges.

428 Simon Henry Gage

of June, that is, in the height of the running season. Some
males exhibited a ridge, but many none, so that it was not
possible to distinguish the sexes with certainty by the external
appearance.

In 1893 it was found that a fully mature lake lamprey ob-
tained April ro, that is about fifty days before the time for
spawning, showed none of the seasonal characters, and hence
it seemed likely as the spawning grounds of the true marine
lampreys were so far from the ocean, that some might set out
on their journey to them before any special, external sexual
characters appeared. To determine this, Mr. Holmes was
asked to secure the first lampreys that should be found run-
ring up the Merrimac, and also some at the very close of the
season. This was done during the present year (1893).
Those caught about May 20, were found without either ridge
or anal fin, and the sexes could not be distinguished by any
external feature. On dissection, the sexual products were
found to be still firmly imbedded in the ovary and testis, or
spermary, and in many of them the alimentary canal was
large, showing little or no signs of atrophy, except at the ter-
minal part. On July 8, there were received four specimens.
Only two were seen by Mr. Holmes after these were caught
so that those sent were among the last to ascend the stream.
These showed in an unmistakable manner the external char-
acters so striking in the two sexes of the spawning lake
lamprey, viz., a ridge extending from the gills to the dor-
sal fin in the male and an anal fin-like crest in the female.
In both sexes the sexual products were partly shed into the
abdominal cavity.

Information from the spawning grounds at the head waters
the Merrimac River in New Hampshire, shows that the dorsal
ridge has been noticed by those familiar with the lampreys in
that region.

The dorsal fins in the male-especially, are in some cases
considerably approximated, but in only a few cases have the
marine lampreys shown an appearance of continuity of the
two dorsals.

It thus appears that the peculiarities so striking in the first

The Lake and Brook Lampreys of New York 429

lake lamprey obtained, are present in the males only, and are
seasonal and very temporary. Furthermore, in addition to
the characters mentioned above as common to the sea and the
lake lamprey, the determination that in the true marine lam-
preys similar sexual peculiarities occur at the breeding season,
removes the last element of doubt as to the very close relation-
ship of the lacustrine and marine forms.

With reference to the specific identity of the lake and the
marine lamprey, it seems impossible to doubt that they were
originally identical, and that the lake lamprey in its somewhat
isolated, inland home has become considerably modified. The
most salient and important modifications relate almost wholly
to the adult form so far as is known; for the larvee of the sea
lamprey from the Susquehanna River agree so closely with
those of the lake that if several living or similarly preserved
specimens of about the same size from each locality were
mingled, it would be difficult or quite impossible to again
separate them. This argument may not be of great import-
ance, however, for as it will be shown later, no definite dis-
tinctions between the larvze of the lake and of the brook lam-
prey have yet been discovered. The modifications in the
adult form are: (a), A very much smaller size for the lake
lamprey ; the average length in the breeding season being fre-
quently less than half that of the sea lamprey. The dorsal
ridge is relatively much more prominent in the male lake
lamprey in the breeding season than is that of the sea lamprey,
and the two dorsal fins are more nearly fused; likewise the
urogenital papilla of the male, the notched appearance at the
vent and the anal, fin-like fold in the female are relatively
greater in the lake than in the sea Jamprey. There is more
frequently a larger number (8 to g,) cusps or teeth to the infra-
oral lamina, or the mandibular tooth-plate, in the lake lamprey
than in the sea lamprey ; and finally there is a greater devel-
opment of cutaneous pigment and it is more diffusely arranged
so that the general coloration of the lake lamprey seems more
uniform, and on the whole somewhat darker than with the sea
lamprey. Indeed, the marine lamprey is designated by the
fishermen as the large spotted lamprey.

430 Simon Henry Gage

Whether these differences, which are mostly of degree, are
sufficient to constitute two different species, has been decided
in the negative by Jordan, and also by Meek (’82, ’85, ’88). If
the criterion of natural and spontaneous interbreeding be taken
to settle the question, it must receive a different answer ; for
the lake lamprey, from its size alone would not form a mate to
the marine lamprey. Of course they are not upon the same
spawning grounds, but any one who has watched the spawn-
ing of lampreys, (see below under spawning) would, I feel
sure, agree with me that the difference in size is so great that
even if on the same spawning grounds, they would be mut-
ually incompatible. It is not asserted that it would be im-
possible to fertilize the ova of a marine lamprey with the
zoospermis of a lake lamprey and the reverse, but the criterion
of modern systematists is, not possible inter-fertility under
very artificial conditions or by the intervention of man, but
the natural interbreeding under conditions to which both
forms have been subjected for many generations.*

Now while I firmly believe that within comparatively recent
times, geologically speaking, the lake lamprey was a true
anadromous marine form it seems to me that at present,
judged by the physiological test of interbreeding, it would be
better to consider the lake lamprey a distinct species, and to
designate it either as Petromyzon unicolor DeKay, or P. dor-
satus Wilder, should the Lake Champlain larvae, upon which

* For possible readers of this article who have not followed closely
the progress of views concerning classification and the nature of ‘a
species,” it may not be out of place to add that by biologists (this
term including both morphologists and systematists) it is believed that
“species”? as an entity in nature, has no existence as was formerly
taught, but that the arrangement of closely allied forms into groups or
“species” is largely for convenience. And as some criterion must be
used, the physiological one mentioned above seems to have gained the
greatest favor.

As is shown in another article in this volume (J. H. Comstock’s),
while the practical aim of classification is to subserve convenience, its
true purpose is to show the phylogenetic relationships of organisms, and
the permanence of any system will depend directly upon the approxi-
mation with which this purpose is attained.

The Lake and Brook Lampreys of New York 431

DeKay’s name was based, prove to be the larvee of the marine
lamprey, which is probable (see Jordan and Fordice, ’85, p.
284).

Distribution of the Lake Lamprey.—It is known by personal
observation and collecting, to be abundantly present in Cayuga
and in Seneca Lakes ; and from information obtained concern-
ing the other lakes and from Lake Ontario, it is believed to be
presentinthemalso. Itis hoped that during the next five years
all of these regionscan be visited and all the lakes and water-
courses of the State investigated to determine the presence of
lampreys and their correlation with those now under consider-
ation. It is hoped also to extend the investigation to the
Great Lakes and to bring any lampreys there living into the
field of comparative observation.

Comparison of the Sexes.—As stated above,,except in the
spawning season there are no definite external characters by
which the sexes can be distinguished. ‘The question then
arises as to the necessary steps to make the determination, at
any other time than in the spawning season. ‘The only way,
so far as is known to the writer, is to resort to dissection.
This is the only way also for determining the sex in the lar-
vee. Upon dissection, even in larvee roo milimeters in length,
the sexes may be quite readily distinguished by examining
the gonads, as the ovary and the ova are markedly larger than
the spermary and sperm mother-cells (Pl. VII, fig. 37, 38).
The determination of the sexes in large, adult forms is much
more difficult. The ovary and spermary are alike single foli-
ated or lobulated organs, and the sperm mother-cells project
from the surface of the spermary as do the ova from the ovary,
so that from the gross appearance alone, it is not easy to dis-
tinguish the two generative glands. When examined as
opaque objects, with a lens or with a compound microscope the
same difficulty is experienced, but if treated by any of the
approved histological methods the true nature of the elements
in each case unmistakably appears (Pl. VII, fig. 27 A, 29 A
and 28, 30).

After one has become accustomed to distinguish the sexes
by dissection, the differences observable by the eye or with a

432 Simon Henry Gage

simple magnifier, are, in most cases, sufficient to make the
diagnosis quite certain. In perfectly fresh specimens the
spermary is semi-translucent and has a watery appearance,
‘while the ovary is much more opaque owing to the food yolk
in the ova. In hardened specimens this difference is lost,
however, so that the determination must be made by compar-
ing the size of the gonads, and the relative size of the ova and
the sperm mother-cells. The ovary is always larger at the same
stage of development than the spermary, and usually the ova
are larger than the sperm mother-cells (Pl, VII, fig. 28, 30).
If one has but a single specimen or is not accustomed to deter-
mine the sexes, the safest way is to make a histological ex-
amination.

In plate I, it isseen that the proportions of the sexes are
markedly different, apart from the greater slenderness of the
female. It was hoped that by a careful comparison of certain
definite and easily determined proportions some guide might
be found by which the sexes could be distinguished at all
seasons and independently of the transient sexual characters
at the spawning season. Careful measurements were made of
specimens that had been subjected to the same treatment, in
fixing and hardening so that the variations due to different
reagents should not complicate the problem. Except for the
lake lampreys taken in the breeding season where the sexes
could be distinguished easily, each specimen measured was
sufficiently dissected to determine with absolute certainty the
sex. ‘The results of the measurements in all the different
forms studied, adult and larval, are given in the following

table :

TABLE showing the total length of the lake, the brook, and the sea
lamprey and the larva; also the distance in thousandths of the total
length from the tip of the oral disc or dorsal lip to the base of the
Jirst dorsal fin, and to the vent; also from the vent to the tip of the
tail. For the purpose of comparing the total length in the various
Sorms and the proportions of like parts of the body.

| MALES. FEMALES.
Total length | bole Tip to Vent to}| Total | ae | Tip to Vent to)
an Dorsal) Vent Tip of Length Dorsal) Vent Tip of
Millimeters. Fin. | ‘| Tail |jin MM. Hine | Si) Abel
365 520 753 247 330 515) (|, 760 240
3238 518 TERT 263 310 516 758 242
310 516 735 265 305 541 73 262
345 507 739 261 345 550 768 232
320 506 750 250 335 537 758 242
300 500 733 267 335 537 746 254
328 518 731 269 315 507 761 239
340 514 741 259 305 557 780 220
310 500 725, | 275 300 533 759 250
275 Sor 728 | 272 310 532 758 242
Av. 322 510 737 263 319 | 532.5 | 757.7 | 242.3
THE LAKE LAMPREY OUT OF THE SPAWNING SEASON.
250 540 760 240 350 | 514 757 243
395 524 747 253 410 512 749 241
405 518 740 260 420 547 750 250
365 548 780 220 281 509 730 270
375 546 | 746 | 254 310;| |) 500, | 726 274
378 579 | 740 | 260 240 | 512 739 | 270
270 500 722 278 285 526 736 264
305 524 A277, 263 250 520 740 260
370 492 730 270 350 542 743 257
Av. 346 530 | 744.6 | 255.4) 3218) 520 740 | 260
JUST TRANSFORMED LAKE LAMPREYS. LARVAL LAMPREYS.
140 485 714 286 185 502 730 270
I4I 500 700 300 132 507 719 281
150 500 700 300 125 504 728 272
152 493 700 300 122 524 739 261
155 500 700 300 108 518 740 260
122 491 hil. 287 112 499 714 286
135 481 703 297 129 488 720 280
127 500 700 300 135 496 718 282
143 517 720 280 135 496 718 282
145 510 717 233 127 504 708 292
Av. 141 497.7 | 706.7 | 293.3/|| 131 | 503.8 | 723.4 | 276.6

434 Simon Henry Gage

SEA LAMPREYS FROM LAWRENCE, MASS., IN THE SPAWNING SEASON.

MALES. FEMALES.
Nn Sea = |
Total length aah Tip to ‘Vent to | Total yg Tip to Vent to
Larie Dorsal} Vent Tip of Length Dorsal} Vent Tip of
Millimeters. Fi SAVE prot WOW Hy) Roe 7 ea
Ain. Fin.
575 525 747 253 645 527 752 248 |
670 507 7g 269 680 519 735 265
670 507 731 ASS | GING 516 728 272
630 523 738 262 680 514 735 265
700 521 728 272 790 | 508 734 266
6yo 514 739 261 660 | 530 742 258 |
690 524 731 269 667 539 749 25007)
740 500 736 264 G757)| SISK aaa 267 |
630 523 746 254 715 5035 | gk 259 |
725 538 744 256) oli! 755 529 754 246
Av. 672 518 737 263 702 520 | 740 260
BROOK LAMPREYS IN THE SPAWNING SEASON.
170 470 718 DO2y Wie 5O' | 536 733 267
167 491 718 282 150 502 720 280
152 513 Te 263 160 512 725 275
143 503 708)" 294° e150 513 733 267 |
148 485 709 291 150 520 738 267
156 512 795 295 145 504 724 276
150 500 720 280 150 500 733 267
167 480 ow 269 163 521 724 276
150 486 700 300 155 530 722 278
150 500 701 299 162 512 722 278
Av. 155.3 494 714.5 | 285.5 || 157.5 | 514.7| 727 273

In each case the specimens were measured without selection, conse-
quently the various sizes are represented as in nature. All the speci-
mens measured had been hardened in Muller’s fluid and alcohol, except
a few of the lake lampreys out of the spawning season. Part of those
were hardened in picric-alcohol and alcohol. Only nine of each sex of
the non-spawning ones were in the collection, consequently only nine
could be measured. In all the other cases ten were measured. The
sexes of the just transformed and the larval lampreys were not separated.

An examination of the table for the lake lampreys in the
spawning season will show that the relative proportions of the
male and the female shown in the frontispiece of this article

The Lake and Brook Lampreys of New York 435

hold good for the lake lampreys generally in the spawning sea-
son, and expressed in words the table shows that the differences
are as follows: (1), That the average length of the male and
the female lake lamprey is approximately the same, being a
little greater in the male. (2), The distance of the base of the
first dorsal fin from the tip of the head is considerably greater
in the female than in the male, or in other words the first dor-
sal fin is nearer the head and farther from the tail in the male
than in the female. (3), In like manner the distance from the
tip of the head to the vent is considerably greater in the
female than in the male, that is, the abdominal cavity is con-
siderably more extended in the female than the male, and, (4),
the tail is consequently shorter. This table shows also, as do
the others, the very great individual variation, so that any
conclusion which might be drawn from the averages in the
table might be invalidated in any individual case. It seems
to the writer, therefore that for the determination of species of
lampreys, the proportions of fixed parts of the body are not
of great value.

Upon comparing the averages in the table for the non-
spawning lake lampreys there appears the remarkable fact
that, apart from the average greater total length of the male,
the proportions are exactly reversed from those obtaining in
the spawning season and the dorsal fin in the female is some-
what nearer the head than in the male, the abdomen shorter
and the tail longer.*

In order to increase the range of comparison, tables are
added of the just transformed lake lamprey, larvee, and the
true sea lamprey.

A glance at the averages for the just transformed lamprey
will show that its tail is relatively longer than in the adult,
the abdomen shorter, and the first dorsal fin nearer the head.
The averages given for the larva are more nearly like those of
the non-spawning adult than are those for the just transformed
ones.

* The results obtained in this table were so unexpected that all of the
specimens were re-examined and remeasured to make sure that the
females had not been put inadvertently in the column marked males.

436 Simon Henry Gage

The table for the sea lamprey shows clearly not only aver-
age greater length but also in each case the greater length
of individuals as compared with the lake lamprey. If one
compares the sexes it will be seen that the average female is
longer than the average male, thus reversing the conditions
obtaining with the lake lamprey. The proportions of the
body in the male and the female are more nearly alike than
in lake lampreys, but the variations are in the same direction
as with the male and female of the lake lamprey.

THE BROOK LAMPREY.

Petromyzon branchialis Linneeus, (1758) Ammocoetes branchialis.
Cuvier, (1827). Plate IV.

Until the spring of 1886 the brook lamprey was not known
in North America outside the Mississippi Valley (Jordan ’85).
The reason for its non-discovery here before, is due to the fact
that so far as is known to the writer, it has never been taken
on the fish of the lake, and so far has only been found during
the spawning season and immediately after transforming in the
autumn. Although the spawning grounds of the brook and
the lake lamprey are the same, the time of spawning of the
brook lamprey is earlier than that of the lake lamprey the two
forms never appearing together. This added to the facts that
at the earlier time the water is liable to be high and often tur-
bid, and that the size issmall, the numbers comparatively few
and the coloration inconspicuous, it will be readily seen why
it might escape observation almost any where.

In the spring of 1886, while trying to determine the earliest
appearance of the lake lampreys on the spawning ground,
three male brook lampreys were found by Prof. S. E. Meek
and the writer. ‘They were compared with specimens from
the Mississippi Valley and found to agree, and in our prelim-
inary paper at the American Association for the Advancement
of Science (’86), one of the points made was ‘‘ The discovery
of Ammocoetes branchialis, [the brook lamprey] east of the
Mississippi Valley.’’

By comparing the mouths of the lampreys in plate VI, the
character of the dentition will be seen to differ greatly from

The Lake and Brook Lampreys of New York 437

that of the lake and of the marine lamprey. This difference
in dentition, and perhaps also some other considerations, have
led some zoologists to divide the genus Petromyzon into two,
Petromyzon and Ammocoetes, and in this case the brook lam-
prey is placed in the latter genus.*

In size the brook lamprey varies from 140 to 200 millimeters.
The color is nearly uniformly dark in the dorsal half and
gradually changes almost to white on the ventral surface.
The two dorsal fins are said to be continuous with only a
sharp notch between them. As the description of this form
in America has been based entirely on specimens taken at the
spawning season (Jordan, ’85, p. 294), the two dorsals could
not be described otherwise than as continuous. But, as with
the male lake lamprey, this is a feature of the spawning sea-
son. In just transformed ones taken in October, there is a
considerable interval between the two dorsals, with only an
exceedingly low ridge connecting them, a ridge which in the
fresh specimen is very difficult tomakeout. The figure given
is of a preserved specimen (PI. IV, fig. 13).

The brook lamprey of North America is believed by Jordan
to be the same species as the brook lamprey of Europe (’85,

* It seems unfortunate to the writer that, if the genus Petromyzon
must be divided, some other name could not have been found for the
brook lamprey. When larval lampreys were not known to be the tad-
pole stage, so to speak of the lampreys, but supposed to be entirely dif-
ferent forms, they were put into an independent genus and called Am-
mocoetes. Upon the discovery, by A. Miller (’56), that the animals pre-
viously placed in the genus Ammocoetes, were merely a larval stage of
a lamprey he made the following suggestion, p. 332: ‘‘Somit ist nach-
gewiesen, dass aus den Neunaugen die Querder entstehen, und dass die
Querder zu Neunaugen werden. So sind denn auch die Querder, wo sie
sich im Systeme bliken lassen, wegen Fuhrung des falschen Namens
anzuhalten, und als Unmiindige ihren respectiven Eltern zu unterstellen.
Der Name Ammocoetes kann fortan nur die Larven der Neunaugen be-
zeichen, wie Gyrinus die der Frosche.’’ Milne-Edwards supports this
suggestion and urges that the term be used for the larvae of the Petro-
nyzontidae as the term ‘‘tad-pole, gyrinus,’’ is used for the frog’s young
(Milne-Edwards, ’57, tome 2, p. 246). Thissuggestion has been adopted
by nearly all morphologists, and the word is frequently used as an adjec-
tive, thus ammocoetes stage, ammocoetes form, etc.

438 Simon Henry Gage

p. 294). Of the European brook lamprey, Seeley (’86, p.
427), says that the dorsal fins may or may not be continuous.
He does not give the season when they are continuous and
when not so, but it may be inferred that they would be con-
tinuous in the spawning season and not in others, as with the
American brook lamprey. If the European and North Amer-
ican brook lampreys are really the same species, the distribu-
tion is remarkably wide, something as with the marine lam-
prey ; it is also apparently less susceptible to environment
than the marine lamprey, for it has apparently been practical-
ly unaffected by the special environment of the inland lakes.
Certainly also the conditions prevailing in the Mississippi
Valley must differ greatly from those found in Europe.

SPAWNING AND THE STRUCTURAL MODIFICATIONS
PRECEDING IT.

Structural Modifications.—Besides the change in the gonads
(ovary and spermary) there occur marked external and internal
changes. Among the most striking ot the internal modifica-
tions is the gradual change of the liver from the characteris-
tic hepatic color to a bright green. With some examples in
which the ova had not yet been shed, there were patches of
green intermingled with the ordinary liver color, but in all
the green color appears throughout the entire organ before
the spawning is completed. This green coloration of the
liver appears to be due to the occlusion of the bile ducts and
the retention of the katabolic products of the organ. In other
than the breeding season, green spherules of liquid of exactly
the same color may be found in great abundance in the termi-
nal third of the intestine.

To the unaided eye the change in the liver is simply one of
color, but with the alimentary canal the striking change is the
diminution in size. From a tube 15 to 20 millimeters in diame-
ter in the lake lamprey, it atrophies to one of 4 or 5 millime-
ters or even less (Pl. VII, fig. 27, 29, 31-32). The atrophy
takes place within two weeks, and begins at the terminal ex-
tremity, and extends gradually cephalad until the whole canal

The Lake and Brook Lampreys of New York 439

appears like a thread. As no foodis taken during the spawn-
ing season there is no necessity for digestion, and in the fe-
male there is no room for the intestine when the ova are com-
pletely matured. This is not the cause of the atrophy, how-
ever, for in the male the increase in size of the spermary is
less marked than of the ovary in the female, leaving plenty
of room for the intestine, still it in many cases is as markedly
atrophied as in the other sex.

While the atrophy of the alimentary canal is going on there
are certain hypertrophies taking place, differing somewhat in
the two sexes, and in the two species. In the male of the
lake lamprey there occurs a great increase of the connective
tissue along the dorsimeson. ‘This begins about opposite the
middle branchiopore and extends to the dorsal fins. This
hypertrophy gives rise to a rounded ridge along the back,
thus adding a very striking feature to the spawning male (Pl.
III, fig. 5, Pl. VII, fig. 31). Asan extension of this hyper-
trophy, the two dorsal fins are approximated to complete
fusion in most cases, but apparently no new fin rays are de-
veloped. ‘The increase in the connective tissue along the dor-
simeson in the female is not marked, except that perhaps the
two dorsals appear somewhat approximated. With the female
there is a marked hypertrophy in the tissue around the vent
thus giving rise to a kind of notch, there is also developed a
fin-like fold between the vent and the caudal fin making the
caudal fin appear to extend to the vent as in the larvee of 15
to 20 millimeters in length. In both sexes the urogenital pa-
pilla is always present, but in the breeding season it is ex-
tended in the male so as to project beyond the level of the
body (Pl. III, fig. 6-8).

The abdomen of the female increases markedly in diameter to
accommodate the maturing ova ; also as shown by the preced-
ing tables, there seems to be an actual increase in the length of
the abdomen, thus shortening the tail. With the male, on
the other hand, the abdomen appears to become relatively
shorter and the tail longer.

The coloration of the lamprey is very modest out of the
breeding season, but in the breeding season there is a great

440 Simon Henry Gage

addition of pigment which appears in the cells of the epider-
mis, the pigment of the corium remaining about the same.
This pigment is yellowish and between the darks spots the
color instead of the usual dull gray appears a bright yellow,
in some almost golden, thus giving a very striking and hand-
some appearance. As is common in the lower forms, this
coloration is more marked in one sex than in the other, but it
is acurious and so far inexplicable fact that some years it
is the male that appears in the gorgeous dress while dur-
ing other years it is the female. For example, during the
present year the females of both Cayuga and Seneca lakes
were brighter by far than the males, while in 1886 when
special note was made of it, it was the males that were more
brightly colored.

So far as comparisons are possible the sea lamprey appears
to undergo the same changes preparatory to spawning that
the lake lamprey does. The specimens personally studied
were on their way to the spawning ground and had not
reached the same and the changes were not yet completed,
but the ridge becomes so prominent during spawning that it
has been noticed by fishermen.

With the brook lamprey the changes in the liver are like
those occurring in the lake lamprey. ‘The change in the ali-
mentary canal may not be quite so striking as with the lake
lamprey. Sufficient material out of the breeding season has
not yet been secured to settle that question. Inthe male the
only observed external modifications are the apparent fusion
of the dorsal fins, and the considerable elongation of the uro-
genital papilla. With the female there is the marked anal
notch and an apparent anal fin but it is not connected with
the caudal fin.

The very striking appearance in the female is due to the
swelling in the second dorsal fin thus filling the space between
the two. At the first of the season this is merely an cedema,
which appears light or semi-translucent, but later, in many
cases, it becomes infiltrated with blood and is bright scarlet
(PIV IV, fig, 11-14).

No dorsal ridge is developed in either sex, and apparently
the general coloration of the body is unchanged.

The Lake and Brook Lampreys of New York 441

Nest Building and Spawning.—As spring approaches the
ovary in the mature lampreys increases greatly in size by the
addition of food yolk to the multitudinous ova. With the
male the actual increase in size of the spermary is not so
great, but the ripening sexual products act as a stimulus in
both sexes, urging them to complete the cycle of existence by
seeking again the clear brooks, far from the lakes, where they
themselves began an independent existence several years be-
fore. Apparently they start out independently from the vari-
ous parts of the lake, each one forsaking its prey, and swim-
ming vigorously or stealing a ride by attaching itself to the
bottom of some boat moving in the right direction. On they
go until the current of the inlet gives them the clue, and they
follow it. Frequently also ordinary fishes, bound on the
same errand, throng the streams, and then the lampreys, with
their inherent desire to be taken care of by the labor of others,
fasten to the larger fishes and are carried along up the stream.
It not infrequently occurs that from the natural inclination of
the stream or from some of man’s obstructions, there are
rapids or dams to be surmounted. Nothing daunted the lam-
prey swims up just as far as possible by a tremenduous effort,
grasping a stone or other solid so that he should not be carried
down stream again, rests for a while and then by a powerful
bending and straightening of the serpentine body, a leap is
made in the right direction and what is gained is saved by
again fastening the mouth toa solid object. This goes on
until the obstacle is surmounted if it is not too great. Then
without waiting to think of the victory gained the lamprey
pushes on up the stream sometimes 8-10 kilometers until clear
water and numerous ripples are found. Just above some
ripple, the lamprey begins to make ready a secure place for
the beginning of a new generation.

From the numerous observations on the brook lampreys it
appears that they are somewhat communistic or gregarious,
and join in considerable numbers, sometimes 8 to 10, to make
a common nest, but with the lake lamprey, while four or five
are sometimes in a large nest it more frequently happens that
but a single pair is present. If the situation is especially fav-

442 Simon Henry Gage

orable one may see five to ten nests within a small radius ;
and perhaps the explanation of the very large nests may be
that several pairs commenced to build in such close proximity
that before they had finished, the nests run together thus pro-
ducing a single large nest with two or more pairs. Whenever
the nest is especially large it has an appearance of a' rounded
ditch, across the stream not parallel with it.

If one observes the nest building throughout the season it
will beseen that those found earliest and those farthest up the
stream, contain but one lamprey, and usually the single one
isamale. It would thus appear that away down in the very
stem form of the vertebrate series the male is the house-builder
and takes the lead in preparing for the offspring. The female
is not by any means a sluggard, however, and when she joins
the male, sets to work with all her might to help complete the
nest.

As stated above, the place most commonly selected for a
nest is in moderately swift water just above ripples. Now to
build the nest the animal has neither hands nor feet, only a
mouth, but the mouth is perfectly adapted for grasping by
suction and so the lamprey heads up stream, fastens to astone,
the stone being frequently more than twice as heavy as the
animal itself. Then with powerful backward or sidewise
swimming movements the stone is loosened and dragged down
the stream a distance a little greater than the length of the
animal, here it is deposited and another grasped and carried
down, andsoon. Ifthe stone issmall it may be carried down
by being lifted free from the bottom (Pl. VII, fig. 39). Some-
times a stone will not yield to the most vigorous tugs. In
such a case it would be very pleasant to say that two or more
joined forces. ‘Two may attach to the same stone if it is large
but two have never been seen by the writer to actually join in
moving astone. On the other hand the smaller stones are
removed from around the larger one, and from time to time
the efforts to remove the large one are renewed until finally it
yields to the combined force of the lamprey and the current.

The nests are usually somewhat oval and the diameter
parallel with the stream somewhat greater than the length of

The Lake and Brook Lampreys of New York 443

the lampreys making them. he central part is usually 15 to
20 centimeters deeper than at the edges so that the whole is
nest-like or dish-like in appearance. At the lower edge is
always a pile of stones which were carried down in making
the nest. As the stones from the upper edge and sides of the
nest are loosened the sand is carried down by the stream and
lodges in the deepest part of the nest. After the nest has a
considerable pile of stones at the lower edge and a good layer
of sand in the bottom it is ready to receive the ees vit
ovulation the female secures herself firmly to a large stone at
the side or upper edge of the nest so that the body can extend
out into the nest, then the male fastens to the female, some-
where near the head, he then winds himself half way around
the female, whereupon the two bend their tails downward and
stir up the sand by the most vigorous movements. Simul-
taneously the ova and the milt are forced out in a stream and
mingle in the water, and also mingle with the sand. ‘The
eggs are coated with an adhesive substance which enables
them to adhere to any solid they come in contact with, con-
sequently they stick to the particles of sand that have been
stirred up in the water and, as the eggs are themselves heavier
than water and made still more so by the particles of sand to
which they adhere, they quickly sink to the bottom before the
current can carry them below the nest ; they are also partly
covered by the depositing sand. If many eggs have been ex-
truded, all are not covered and the bottom of the nest may be
quite thickly strewn with them. In nearly all cases some re-
main uncovered. After the pair have ‘‘shaken together”’ as
the ovulation is called, they separate and commence at once to
remove stones from the upper edge and sides of the nest and
pull them down stream as if to enlarge the pile at the lower
edge. This was at first puzzling, for the nest is apparently
completed before the ovulation begins. The explanation soon
became evident, for while immediately after ‘ shaking to-
gether” there might be many uncovered eggs, in a very short
time they all disappeared, being covered by the sand that was
loosened by the removal of the stones and carried down the
stream by the current.

444 Simon Henry Gage

The ovulation is repeated at intervals until the eggs are all
extruded. If during the spawning the lampreys are disturbed
so that one or both leave the nest they soon return. After
thé spawning is completed, however, they leave it for good
and a newly arrived pair may utilize it and thus save them-
selves much labor. ‘This is proved by catching a pair ina
nest and finding the nest occupied by another pair on return-
ing some days later. It is also proved by the fact that from
the same nest, during the middle and latter parts of the
spawning season, one can obtain eggs apparently but just laid
and in the earliest stages of development, and embryos 8 to 10
millimeters in length.

The duration of the spawning season for the brook lamprey
is about two weeks. ‘Thev appear earlier than the lake lam-
preys and all disappear before the lake lampreys arrive. Fre-
quently the lake lampreys utilize the nests of the brook lam-
preys as they do the nests of earlier pairs of their own species,
as described above. The time for the spawning of the brook
lamprey usually begins about the 8th of May and lasts till
about the 20th. The lake lamprey usually appears about the
25th of May and disappears about the first of July, the height
of the spawning time being about the roth of June. ‘The
time varies from year to year and corresponds in general to
the advance of the seasons.

As one watches these humble creatures with their pigmy
brains and observes with what exactitude they recognize that
‘to rule nature one must obey her,’’ there comes to one the
feeling that the germ, at least, of the highest achievement is
present in these our lowly vertebrate allies and that the abyss
separating us from them is not so wide after all. If it is urged
that all this precision and the resulting efficiency is due to
blind instinct then it may be answered that an instinct which
guides its possessor to apply the appropriate means to accom-
plish a desired end, to overcome difficulties not previously en-
countered by the race and guides it to make the most of favor-
ing circumstances whether they be common ones or those
never before utilized, then it must be said that such a guide
is a pretty good thing to have after all, and about as valuable

The Lake and Brook Lampreys of New York 445

to its possessor as something else, although the something
else may have been dignified by the name of reason.

Fate of the Adult Lampreys after Spawning.—As to what
becomes of the lampreys after spawning the opinion of authors
is conflicting. A. Miiller (’56) says concerning it that from
the dead ones found at the close of the spawning season and
from the fact that in the ovary were eggs of only one size,
probably death followed the egg-laying asin case of many in-
sects. Couch (’65), in his work on the fishes of the British
Isles remarks concerning this point (Vol. IV, p. 391-392),
‘‘ As this species of lamprey [the sea lamprey] enters rivers
for the purpose of spawning in the spring, this is the season of
highest perfection ; but immediately after the shedding of the
roe so great a change takes place, that they are not only
weakened and emaciated, but it has been believed that death
is commonly the result. But this last supposition at least is
TOE COeebay ss 1320 Soon after spawning the parent fish re-
turns to the sea.’’ Seeley (’86), says concerning the sea lam-
prey, ‘After spawning the fish isexhausted and goes down to
the sea.’’ Of the river lamprey he says, ‘‘ After spawning
the lampern usually dies ;’’ and of the brook lamprey, ‘‘After
spawning theold fishes probably die.’’ Benecke, (80-81), as
quoted by Goode (’84), remarks upon this point, ‘‘ After the
eggs have been deposited, the lampreys die.’’ The proof in
each case is not proof, but probability, from each author’s
standpoint, the strongest argument being that of A. Muller,—
that the ova in the ovaries are all of the same size.

Unfortunately the fate of the lampreys after spawning has
not been determined by the writer, although special pains
were taken to determine it. Several facts seemed to indicate
that, with both species, most of them return to the lake after
spawning, for in the middle and later part of the season many
lampreys are found going down the stream or attached to
stones below the nesting places. On examination such lam-
preys were always with empty gonads. As to their death on
the spawning grounds, especial care was taken to look for the
dead, but in all the years of investigation not more than 10
dead ones were seen. This does not indicate the number that

446 Simon Henry Gage

might have actually died, however, for birds of prey hovering
over the water would be very liable to catch any that were zz
extremis. Nature has so many ways to dispose of dead bodies
that the number seen even on careful investigation is small,
even though the actual mortality may be great.

In the last part of the season many were affected by sapro-
legnia, especially where the epithelium had been injured by
the attachment of another lamprey. An additional argument
in favor of the death of the lampreys after spawning, is the
condition of the alimentary canal and the liver. ‘There would
need to be almost a new building of the alimentary canal.
And then enforcing the argument from the absence of small
ova in the ovary after spawning it is to be said that even in
the larva the eggs are of considerable size (Pl. VII, fig. 38),
so that if the lampreys that had spawned were to return to the
lake and re-acquire ova a greater development in the ovary
would be required than takes place between late larval life
and sexual maturity ; a development requiring from two and
one-half to three and one-half years in the lake laimprey.

An effort was made to determine the matter experimentally
by transferring lampreys that had spawned to water contain-
ing cat-fish (Amzurus nebulosus), as the lampreys seem partic-
ularly fond of cat-fish. The conditions were very unnatural
as the only available place was a cold spring. The cat-fish
soon died and the lampreys also, without attempting to feed
on the live or dead fish. It seems to the writer that the
experimental method is the only one promising satisfactorily
to settle this vexed question, a question important alike from
the scientific and from the economic stand-points. If a pond
through which the water from the stream in which they spawn
or one connected with the lake were stocked with cat-fish or
suckers (Amzurus or Catostomus), fishes which are frequently
attacked by lampreys, and then if lampreys were placed there
after spawning one could determine the duration of life after
spawning under natural conditions of water and plentiful food.
There is no difficulty whatsoever in keeping lampreys alive
and in good condition out of the spawning season even ina
large aquarium where there are other fishes. Indeed the lam-

The Lake and Brook Lampreys of New York 447

preys are so vigorous and aggressive that, when hungry, they
will attack the ganoid fish, Ama calva, and rasp away the
scales sufficiently to extract blood from the amia. If they
naturally return to the lake and resume their ordinary mode
of life there should not be the slightest difficulty in deter-
mining it under the natural conditions just mentioned. It is
hoped that suitable facilities may be afforded at some future
time to settle definitely this important question and also sev-
eral others that have arisen in the study of the various stages in
the life history of these animals.

DEVELOPMENT OF THE OVUM AND LARVAL LIFE.

The ripe ova are about one millimeter in diameter and
nearly spherical. They are very opaque from the abundance
of opaque food yolk, and each is surrounded by a thin layer
of material which is very adhesive upon exposure to either air
or water, consequently the eggs adhere to whatever solid body
they come in contact. The adhesion is not very permanent,
however, as after a day or two they are easily detached.

Some eggs of the brook lamprey were fertilized and kept
until the larvee were hatched. The segmentation is total and
unequal asin the amphibia, and the development proceeds
with great rapidity ; after eleven days the heart beats are
plainly visible. In 14 days the mouth is shark-like and on
the ventral side, and the blood vessels extend around the
gill slits. In 18 days the eyes are clearly shown, respiration
and the movements of the velum are evident and the mouth
has assumed the larval appearance with. the hooded dorsal lip
so characteristic of the older larvee. ‘The fins are represented
by a continuous fold from a point about opposite the 4th
branchiopore along the dorsimeson and around the tail on the
ventrimeson to the vent. In swimming the larva goes with a
wriggling motion ; it holds itself dorsal side up as do the older
larvee when swimming and like the older ones rests on the
side when quiet. .

As was shown by Calberla (77), the nervous system de-
velops as a solid cord and becomes a hollow tube only later in
the course of development. In this respect the lamprey

448 Simon Henry Gage

agrees with the teleosts and the ganoids, so far as they have
been investigated (Calberla, ’77, Balfour, ’81). Other refer-
ences to the embryology of the lamprey will be found in the
bibliography at the end.

In nature the young larve live in the sand in the bottom of
the nest where the eggs were deposited by the parents. Some-
times the larger ones are found most abundantly in the sand
and gravel under the pile of stones bordering the lower edge
of the nest. This may have given rise to the prevalent notion
that the pile of stones is the real nest. One can obtain the
embryos very easily by shoveling up the sand from the bottom
of anest. If water is then added to wash away the mud, and
the sand is shaken lightly, the eggs or embryos or both appear
on the surface, and are readily detected by the light color of
the eggs or the greenish color of the food yolk in the embryo
of 8 to 1o millimeters. After the larvee are 10 to 15 milli-
meters in length it is far more difficult to secure them as they
are less conspicuous and far more active. Then too, they ex-
hibit already the habits of older larvee and very quickly dis-
appear in the sand.

The exact time the larvee remain in the nest and the stage
of development reached by them before leaving it is not
known with exactitude. Already on July 31st, larvee 30 mm.
long were found while searching for large larvee. A few days
later a thorough exploration was made by my assistant, G. S.
Hopkins, D.Sc. both in the nests and in the sand banks at
the concavity of the stream where the larger larvz are found
throughout the year (Pl. VII, fig. 40). None could be found
in the nests at the bottom of the stream, but in the sand at
the side of the stream many of all sizes were obtained, some
of them being only 16 millimeters in length. Consequently
it is believed that the larvee remain in the nests only about
one month or until they attain a length of 12 to 15 milli-
meters. Whether they voluntarily leave the nest or whether
the rapid current of some sudden rise in the stream, as after a
heavy storm, washes them out of the nest is not known. It
is believed, however, that they leave the nest voluntarily, for,
on account of the conformation of the nest, any moderate in-

The Lake and Brook Lampreys of New York 449

crease in the stream would tend to cover the larvee still
deeper.

Larval Life.—After the larve leave the nest they wander
down the stream until some suitable place composed of sand
and mud is found. ‘This suitable place is most often in the
concavity of the stream where the water flows slowly and
there is not great danger of being washed away by every
freshet. Judging from specimens in the laboratory that were
placed in glass vessels with water, and sand from the native
habitat, each larva has a canal or burrow of its own. This
burrow usually opens on the surface of the sand. In this
burrow the larva remains, changing its position at will and
also making a new burrow with a new surface opening as in-
clination or necessity demands. In those observed in a glass
vessel where there could be no doubt, the canal was curved,
the convexity of the curve being downward (Pl. VIII, fig.
49). ‘The larva was curved correspondingly ; but the dorsal
side was always up as shown in the drawing. Often in mov-
ing to and fro in the canal the tail would be higher than the
head. If disturbed the larva leaves the burrow and worms
itself through the sand with great alacrity. They donot leave
the protection of the sand if they can possibly avoid it. In
their natural home beside the streams, they are usually only a
few centimeters under the surface of the sand and frequently
not more than 15 to 40 centimeters below the water level. In
taking them the sand is shoveled up from the stream and car-
ried out to the shore and placed on the bank or upon some-
thing else so that the water may drain away. As soon as the
sand is pretty well drained, any larvee present wriggle out to
the surface where they can be seen. To obtain the smaller
ones it isnecessary to take somewhat more care and spread the
sand out in a thin layer ; sometimes also it is advantageous to
pour water over it.

The way in which the larvee enter the sand from the water
and the way they move around in the sand was very easily
and satisfactorily demonstrated by placing some of the sand
from the native habitat in a glass dish and partly filling it
with water. The sand was washed to avoid turbidity then a

450 Simon Henry Gage

larva introduced. If the creature is vigorous it almost im-
mediately commences to bury itself, and in the following
manner: It stands almost vertically on its head and then
makes most vigorous swimming movements. At the same
time the head with its hood-like dorsal lip is twisted from side
to side something as one turns the hand in trying to force an
awl into wood or leather. Inashort time the animal will
bury itself to about the extent of its branchial apparatus, that
is until the sand affords a kind of hold for it. The animal
then ceases to go directly downward, but with a serpentine
movement, constantly twisting the head from side to side to
open the sand, it goes more nearly horizontally till the body is
entirely covered. Once in the sand the creature moves around
with great ease, the head and hood-like dorsal lip serving by
their stiffuess and mobility to part the sand. It soon makes a
burrow and the opening to the surface of the sand. In this
burrow it can move to and fro at will. The sand seems to be
packed in some way so that it does not cave in and fill the
canal.

In discussing the habits of the larvee it is frequently stated
that they havea great dislike to light and swim around in the
vessel in which they are placed until exhausted and they die.
From my own experiments the larvee do not seem to have a
great dislike to light, but rather there is a sense of insecurity
when not covered by the sand. Experiments were carried on
for weeks with those in glass vessels to see if, when the bur-
rows were next the glass, and that side turned to the light the
larvee would move away from the light, as they could very
easily do if desired. Sometimes they would make a new bur-
row on the side from the light, but nearly as often the change
would be made from the shaded to the light side. It thus ap-
peared that if the animals were protected by being ina normal
habitat in the sand the restlessness mentioned by authors as
due to light would not be observed. Furthermore one was
kept alive in a small globe, hanging, glass aquarium with other
aquatic animals from Christmas till the following May. In it
there was no sand present and the animal was thus constantly
exposed to the light throughout the day.

The Lake and Brook Lampreys of New York 451

Whenever a larva swims it is always dorsal side up,
but in resting on the top of the sand or on the bottom of a
vessel of water it lies on the side. Apparently the side on
which it rests is a matter of chance as it is sometimes the left
and sometimes the right.

Comparison of the Larva with the Adult.—As one watches
the development of a lamprey’s ovum it is seen that in a
very short time, 10 to 15 days, the embryo assumes characters
markedly like its parent ; but a closer study will show very
marked differences. Instead of a circular, sucking mouth
armed with teeth, the mouth is hooded and the entrance
guarded by a very perfect sieve (Pl. VI, fig. 22), and between
the mouth and gills will be seen a reddish body that moves to
and fro rhythmically and in unison with the movements of the
branchial apparatus.

If the branchial chamber is explored the seven branchial
openings on each side will not be found to open, each into a
separate sac or pouch, but into a large common chamber, a
chamber serving also for an cesophagus. The eyes, too al-
though visible do not reach the surface, but remain quite
deeply imbedded. Many other structural differences occur,
but a sufficient number have been named. In habits the dif-
ference is as striking as the difference of structure ; the parent
is a free-booter, the offspring lives an orderly and isolated life.
It is no wonder that naturalists and fishermen should have
agreed that they were different animals ; that they were dif-
ferent stages of the same animal probably did not enter their
minds.

So strikingly unlike are frogs and their young, the tad-
poles, that it would be deemed almost incredible that one is
the offspring and would assume the appearance of its parent
if the facts were not forced upon every one that is at all ob-
servant. The transformations in insect life, too, are even
more marvelous, but from their frequency are taken as matters
of course. Apparently, a fisherman and naturalist of Strass-
burg Leonhart Boldner in 1666, knew of the metamorphosis
of the lampreys, and that the larvee were larve and not dis-
tinct animals. But this was lost sight of, and the knowledge

452 Simon Henry Gage

of the scientific world dates from the discoveries and the pub-
lication of A. Miller, 1856. (See note on p. 437 above).

Duration of the Larval Period.—The time required for the
larva to prepare itself for adult lifeis not known. It has been
estimated at three to four years. The reasons for assigning
that time are: The larve that may be obtained from the
natural habitat at any season of the year are of such varying
sizes that it is believed that from three to four generations are
represented. The first of September for example, one may
obtain from the same bank or bed, as the fishermen call
it, lampreys in various stages of transformation, larvee
about two-thirds as large as the transforming ones and so on
down to the generation of that year, which are from 15 to 40
millimeters in length. This like the supposed death of the
adults after spawning is one of the questions that must be de-
termined experimentally. As the larve are easily kept for
six months toa year in an aquarium with sand, it would doubt-
less be very easy to keep them from the egg until transfor-
mation, by imitating closely the conditions obtaining in their
native home.

Transformation and Duration of Adult Life.—When the
larvee attain a length of 120 to 160 millimeters for the lake
lamprey or sometimes as great a length as 200 millimeters for
the brook lamprey, they transform to the adult condition.
The brook lamprey does not apparently increase in length
after transformation, for many of the transformed ones at the
spawning season are of less size than the just transformed
ones. ‘There is, however, some increase in the bulk of the
body, and a considerable increase in the gonads. As shown
in plate vii, figures 35 and 36, the ova and the sperm mother-
cells are in about the same stage of development as the lake
lamprey six months beforespawning. It is believed from this
that the brook lamprey attains nearly its full growth before
transforming, and that the free life in the water is only about
six months, that is from the transformation in the autumn,
August and September and perhaps October, till the following
May.

The lake lamprey upon transforming is only about 4 to

The Lake and Brook Lampreys of New York 453

ith the length and probably not one 7th bulk of the spawn-
ing ones. The gonads are small and the ovary and ova are
minute but perfectly recognizable on transforming. The com-
parative size is given on plate vii. ‘The gonad of the male is
very small indeed, and the sperm mother-cells not far ad-
vanced. To attain the size and maturity of the spawning
ones it is believed that two or three years are required. ‘This
conclusion is reached by the size and development of indi-
viduals caught in various months of the year. For example,
while the lake lamprey is spawning, specimens have been
taken from the lake with the intestine large and full of blood
and with ova of about half or one-third the size of the mature
ones. In others of about 200 or 225 millimeters length the
ova are still smaller. The smallest ones are supposed to have
transformed six to eight months previously and those next in
sizea year and a half earlier. The absolute bulk of fishes de-
pends so largely upon the food supply that size of body alone
is not a good test of maturity. The size and stage of develop-
ment of the sexual organs is a safer guide. Following this
guide it seems very probable that it requires either one year
and a half, two years and a half, or three years and a half for
the small, just transformed larva of 150 millimeters to attain a
length of 450 millimeters, or rather that ova of the size shown
in plate vii, figure 34 A, require that time to reach the size and
maturity of the egg shown in 32 A. This question like those
previously mentioned can be definitely settled only by rather
expensive experimentation. That it has an important scien-
tific interest all biologists will agree ; that it also has a very
important economic bearing may beseen also when one reflects
how many food fishes are either destroyed or greatly weak-
ened by the parasitic adult lampreys.

The transformation. of the larva into the adult is usually
described as taking place in a few days. In three or four (en
trois ou quatre jours) according to Bujor (’g1), for the Euro-
pean brook lamprey (P. planeri, or P. branchialis). The time
given by Muller is longer, 10 to 26 days. My own observa-
tions accord more with those of Miller. The first external
signs of transformation is the appearance of the eyes upon the

454 Simon Henry Gage

surface and the development of the sensory papillae in the
characteristic curved line interrupted by the eye (Pl. VIII,
fig. 50). Looked at ina strong light the eyes appear ina
dorsal view like clear spaces; looked at from the side the
black pigment, especially in the dorsal half, is very evident.
The mouth in this stage is precisely the same as the larva to
all appearance and so is the general coloration of the body.
In a somewhat later stage the eyes are still more evident, but
appear dull and as if covered by only a semitranslucent mem-
brane. The mouth has no longer the wide open appearance
of the larva but has become greatly contracted ; the dorsal and
ventral lips are becoming fused and the oral tentacles arrange
themselves as shown in figure 23. The appearance is exactly
as if the papillze or tentacles were to form the basis or found-
ation for the future teeth. Several days (20) later the eyes are
less turbid and the oral tentacles have lost their branched ends
and have become blunt papilla. In one kept in a large glass
vessel with sand and stones, changing the water frequently, the
changes just described were gone through in 25 days. But
it is believed that nearly as many more days are needed to de-
velop the large, clear eyes of the adult form and the enlarged
sucking disc with horny teeth ; so that with those investigated
by me the metamorphosis cannot be said to goon very rapidly,
but rather, very slowly. One of the striking external changes
also is the gradual darkening from a brownish gray to a blue
black, which is so rich and soft that it appears like velvet.
The pineal eye then appears like a snow white, rounded spot.
Later it is partly overshadowed by the thickening epithelium
and looks dull (Pl. VIII, fig. 50). A striking change in atti-
tude also occurs. ‘The animal rests dorsal side up and not on
the left or the right side as with the larva.

Corresponding with the external changes, there are profound
internal changes. The intestine no longer opens into the
bronchus, but a new cesophagus is developed along the dorsal
wall of the bronchus and finally opens cephalad of it very
near the mouth. The gills cease to be in a common chamber
and are divided, each one forming a pouch which opens to
the exterior by the branchiopore as in the larva and into the

The Lake and Brook Lampreys of New York 455

common bronchus by a small opening about the size of the
external opening. The velum gradually atrophies and soon
almost disappears. It is stated by Bujor that in the metamor-
phosis, the tissues return to an embryonic condition and then
are reformed into the tissues of the adult. ‘‘Les différ-
ents tissus des organes larvaires se régénérent complétement
pendant la métamorphose,’’ (Bujor, ’91, pp. 77, 88). Es-
pecial care was taken in investigating the transformation to
determine something of the activity of the animals and their
mode of life. The first transforming ones were obtained the
last of August. The last just transformed ones from the na-
tive habitat were obtained the middle of October. Aquaria
were prepared with sand and gravel, thus imitating as closely as
possible the natural conditions. Into these aquaria the trans-
forming animals were placed as they were received and each
aquarium carefully labeled with the date and the stage of de-
velopment. Allofthe animals that were in good condition very
soon disappeared in the sand. Those with a fully developed
sucking mouth surrounded by the oral fringe of papillee (Pl.
VII, fig. 19-21), also buried themselves. Some of these were
so far advanced that the horny tips to the teeth were already
visible with a lens. It is therefore believed that the animals,
in nature, remain under the protection of their early home
until they are fully armed and ready to get their food in the
usual adult fashion.

The activity of the animals seemed not at all lessened. In
a vessel of water they swam with the same vigor as untrans-
forming larvee and frequently like them made vertical leaps of
Io to 20 centimeters to escape from the dish. The respiration
seemed in no way interfered with. So far as certain struct-
ures are concerned, at least, there seemed no tendency to re-
turn to anembryonic condition. The ova, for example, in 100
millimeter larvae have the unmistakable characters of the ova

in young adults. None of these characters are lost dur-
ing transformation. Certain profound changes take place,

that is certain, but these changes appear to the writer rather
the additions to or rearrangement of tissues common alike to
the larva and the adult, new structures also appear and purely

456 Simon Henry Gage

larval organs like the velum atrophy. So far as the liver and
its duct are concerned it is almost universally stated that in
the European brook lamprey the bile duct loses its connection
with the intestine upon transformation. ‘This is the con-
dition in the lake lamprey and in many examples, at least of
the sea lamprey. It is only upon the atrophy of the intestine

at the breeding season that the-bite-cret—ts-0ttitrded__Lhey
the liver assumes an emerald green color as stated above (p.

438). From the numerous observations made by the writer
on transforming lake lampreys and sea lampreys from the
Susquehanna River, there is not a period of quiescence com-
parable to the pupa stage of insects ; such a pericd would be
expected with so great a histolysis and subsequent histo-
genesis as described by Bujor (’91) for the European form of
the brook lamprey.

In collecting the transforming lampreys the same method is
employed as described above for the untransforming larvee.
It is well, however, to have a dip net with a long handle, for
the transforming ones more readily leave the sand when it is
disturbed by the shovel, and attempt to swim away in the
stream. With the dip net these may frequently be caught.

Up to the present time there has been no way discovered of
distinguishing the larvee of the lake and of the brook lamprey.
As the two species occupy the same spawning ground and
sometimes spawn in the same nest great care is necessary in
order not to confuse the two. After the larvee leave the nest
they apparently go to the same sand bed. ‘There are certain
peculiarities about the one figured in plate iv that might lead
one to diagnose it as the larva of a brook lamprey. Here
again, only a carefully conducted experiment would give
definite and reliable information.

If one can keep the transforming ones alive until the dental
papilla appear on the oral disc the distinction is as clearly
marked in the two species as in the adult, for there is the
same definiteness of arrangement, and the same arrangement
of dental papillae in the young as in the horny teeth of the
adult. The general appearance of the brook and the lake
lamprey is also as strikingly unlike at this stage asin any sub-
sequent one.

The Lake and Brook Lampreys of New York 457

ECONOMICS.

From the human stand-point, beneficial or injurious, as ap-
plied to an animal or plant relates solely to the supposed ad-
vantage or disadvantage to the human race that it subserves.
No doubt from the economical stand-point of the animal or
plant, judge and prisoner would change places. In this eco-
nomical consideration two questions arise: First, in what
way does this animal or plant subserve man insupplying food
or clothing and secondly, does it destroy, for its own use, food
or clothing that might otherwise be utilized by man.

To answer these two simple questions it is only necessary
to find out the food of an animal, and also the animals for
which it in turn serves as food.

Food and Uses of the Larva.—The food of the larva consists
of microscopic organisms separated in some way from the
constant stream of water drawn into the combined cesophageal
and branchial chamber. It thus appears that in its larval life
the lamprey is not injurious to man by destroving food that
he wishes, directly or indirectly, to utilize for his own benefit.
On the other hand, from the tenacity with which the larvee
retain life they have been found excellent bait for all kinds of
ordinary carnivorous fishes. The fishermen along the Cayuga
and Seneca Lake inlets make considerable use of the larvze
for bait ; this form of bait has not up to the present been much
used in the lake fisheries, as apparently its excellence is un-
known. At Owego, on the Susquehanna River, however,
quite a business is carried on in supplying larval lampreys to
fishermen of all kinds, and many are shipped to distant points.

As no distinction is yet known between the larvz of the
brook and of the lake or sea lamprey, all larvee may be classed
as non-injurious and as positively beneficial by serving for
bait, and thus in aiding man to obtain food fishes.

Economics of the Adults.—Unlike the larva the adult lam-
prey is largely or wholly parasitic, and in obtaining its food
destroys or injures the fishes used by man as food. It is
stated by Gunther (’53, p. 133), that the food of the lamprey
(P. marinus and P. fluviatilis) consists of worms and insects,

458 Simon Henry Gage

and fishes to which it attaches itself. He is followed by
nearly all authors, more especially in describing the food of
the brook and river lampreys. From personal observations,
the food of the brook lamprey of the lake region has not been
determined, as none have been taken out of the breeding
season except those which were transforming. From their
small size (150-200 millimeters) and the probable shortness of
adult life, the injury to the larger food fishes in any case must
be considered slight. This is especially true of the region
under consideration, for in addition to the smallness in size
and probable shortness of life, they are fewin number. While
it is not at all difficult to get 200 to 400 lake lampreys from
the Cayuga Lake inlet during one spawning season, one must
work quite persistently to obtain 75 to 100 brook lampreys.

With reference to the usefulness of the brook lamprey in
New York, it may be put down as nil. In England, accord-
ing to Couch (’65) and Seeley (’86), the adult river lamprey
which is very closely allied to the brook lamprey, or speci-
fically identical with it (Schneider, ’79, Shipley ’87), was
formerly much used in the cod and turbot and other deep sea
fisheries. It is stated by Seeley that the lamprey fishery be-
ginsin August and continues till March, and that in that time
as mally as 450,000 have been taken and used as bait in one
year.

With reference to the lake lamprey, the conditions are quite
different from those described for the brook lamprey. In the
first place the lake lamprey exists in large numbers, and lives
a parasitic life from one and a half to three and a half years.
Of all the specimens obtained out of the breeding season,
either the digesting part of the alimentary canal was empty
or it contained blood. No partly digested worms or insects or
small fish or fish flesh were ever found, although diligent
search was made; consequently it is believed that the lake
lamprey is wholly parasitic during its adult life and lives on
the blood sucked from other fishes. From the structure of
the mouth and the opening to the cesophagus in the adult, one
might also infer that liquid food was used and that this was
obtained by suction as with a leech.

The Lake and Brook Lampreys of New York 459

From observations on the lampreys in flat sided, glass jars, and
by experiments in allowing them to fasten to the hand, the pro-
cess of attachment appears to be as follows: The oral disc is
quite widely expanded and pressed suddenly against whatever
the lamprey wishes to fasten to. Almost instantly the mouth
is somewhat arched and any water that may be present drawn
into the bronchus. ‘The circum-oral fringe of papillae with
the continuous fold of mucosa bordering the fringe, serves to
fill any irregularities and make the contact, air and water
tight, so that upon lessening the pressure within the mouth
the adhesion becomes very perfect. So perfect isit, that sucha
hard scaled and vigorous fish as the ganoid, Amza calva, can
rarely prevent the attachment and adhesion although the most
violent efforts are made. If they are attached to stones of
moderate size, the stone is frequently brought out with the
lamprey if the animal is jerked up suddenly. In letting go
its hold all that is necessary for the lamprey is to fill the disc
with water from the respiratory bronchus, whereupon suction
ceases and the animal is free. In feeding, the sharp teeth
pressed against the skin of the animal to which it is attached,
naturally calls the blood to the place. This hyperzemia is
caused even more by the suction. At the same time the piston-
like tongue with its powerful muscles and the saw-like teeth
soon rasps a hole through the skin. The blood is then sucked
from the fish and swallowed. The whole operation is some-
thing like the extraction of blood by a leech. The lamprey
may remain upon a fish so-long as it supplies sufficient nutri-
ment. Sometimes the fish becomes exceedingly pale and
weak so that it floats near the surface. In such a case, the
fishermen know immediately that there is a lamprey attached
to the fish, and, with a dip net, usually have no great trouble
in catching both. ‘The birds of prey also make this their op-
portunity and frequently carry off the floating fish, the lamprey
sometimes remaining attached until it has been carried a con-
siderable distance into the air.

According to one intelligent fisherman, who has spent near-
ly fifty years by the lake, some of the fishes, when a lamprey
attacks them, will rise to the surface and turn over on the

460 Simon Henry Gage

side so that the lamprey’s head and branchial apparatus are
out of water. By this means the lamprey is partly suffocated
and lets go its hold, thus freeing the fish.

That the injury to the food fishes is very great may be in-
ferred from the fact that sometimes out of 15 cat fish caught
on a set line in one night, 10-12 have great raw sores where a
lamprey has attacked them. In the spring, too, when the
suckers (Ca/ostomus) run up to spawn, very many of them
carry a lamprey, and naturally by the great drain of blood
that it causes, the fish must be weakened, so that obstacles on
the way to the spawning ground are less liable to be sur-
mounted than as if the fish were in full vigor.

As stated above, during a single season over a thousand
lampreys were caught in the Cayuga Lake inlet. If these
had spent from two to three years infesting the fishes of the
lake they probably did more to reduce the number of avail-
able food fishes than the fishermen. :

In 1891, on account of the lack of rain and the clearness of
the water in the streams at the spawning time, conditions
were very favorable for determining the number of nests in the
Cayuga Lake inlet. This was done for about to kilometers,
and 400 nests found. If each nest had been inhabited by
a single pair, then 800 lampreys visited the inlet for spawing
during that spring; but in 1886 over 1000 were known to
have been caught from the inlet, and furthermore by direct
observation some of the nests are utilized by at least two
pairs of lampreys, so that probably the 4oo nests represented
a visit of rooo to 1200 lampreys and perhaps more. The
males are usually somewhat in excess so that probably there
were from four to six hundred females. The number of eggs
in the ovary of a lamprey of moderate size was estimated in
the usual way by weighing a small piece and counting the eggs
in it and then weighing the whole ovary. The eggs
present in the whole ovary is then estimated by a simple
proportion. In the case mentioned, the ovary was found to
contain 65,000 ova. (A sea lamprey from the Merrimac
River was found, by the same method, to contain 236,000
ova). If each of the females that were on the spawning

The Lake and Brook Lampreys of New York 461

grounds that year deposited 65,000 ova there would have
been laid 65000 X 400—26,000,000. Many of the ova fail of
fertilization and many also fail to develop even if fertilized so
that of the possible twenty-six million young lampreys from
the spawn of a season, possibly not over 4 or 5 thousand
reach the sand beds ; and from the further decimation of these
the numbers in the lake remain approximately uniform as
with other animals in nature.

Ridding the Lakes of Lampreys.—From the foregoing ac-
count of the life history of the lamprey it will be seen that it
has a single very weak point, viz., leaving the lake and
running up the tributaries to spawn. ‘This seems to be the
only weak point at which the lamprey can be attacked with a
hope of exterminating it. This point is rendered still weaker
from the fact that in Cayuga Lake, and in Seneca Lake, so far
as explored, the lampreys run up the inlet at the head of the
lake only, and do not spawn in the tributaries entering the
lake at intervals on each side. Some of the lateral tributaries
seem well adapted for the lamprey’s spawning grounds ; these
streams are used by other fishes, but the most careful ex-
ploration under favorable circumstances gave no sign of the
lampreys. Also, as will be seen by examining the map (PI.
II), the large creek (Fall Creek) entering the head of Cayuga
Lake by a separate entrance, has never been known to con-
tain lampreys. Careful personal search was made for several
seasons and inquiry made of those familiar with the creek,
but none were ever found or heard of. This may be due to
the nearness of the falls in the course of the stream. The
creeks joining the inlet (Cascadilla.and Six Mile creeks) con-
tain them. Formerly they were very abundant in both, but
the water is not now so plentiful and then both extend for a
considerable distance through the city. At present it is the
main stream that is most frequented and employed by the
lampreys for spawning. The lampreys must be destroyed
before spawning if they are to be exterminated. Nothing
would be easier than to do this. A dam with a fish-way, the
fish-way leading into an isolated enclosure where the
lampreys could be easily removed and disposed of, or a weir

462 Simon Henry Gage

of some kind could be constructed at slight expense. If this
could be continued for three to four years in all the lakes and
in the Oswego River, the race could be extinguished and the
lake wholly freed from their devastations. So vulnerable
is this point in the lampreys defenses, that even in great
rivers, where dams exist, the fish-ways could be utilized
to free the river of lampreys as well as to allow the more
valuable food fishes to run up and spawn. ‘To be sure, in the
Merrimac and Connecticut rivers the lampreys have been
largely utilized for food, but if one considers the damage
these monstrous parasites must do to the ocean fishes it will
be seen that too dear a price is paid for the food they
furnish. It seems to the writer that from every economical
standpoint it would be advantageous to rid the world entirely
of the lampreys. It would certainly be greatly to the ad-
vantage of the fisheries of the State of New York if all were
destroyed. Naturally, however, the student of biology must
mourn the loss of a form so interesting and so instructive.

RESPIRATION AND THE RESPIRATORY MECHANISM IN THE
LARVA AND IN THE ADULT.

In the lampreys, the respiration is wholly aquatic. They
do not come to the surface and take in air as do many fishes.
As the dissolved oxygen is only 6 cubic centimeters in 1,000¢. c.
of water, while in the air there are 209 c.c. of oxygen in 1,000
c.c. of air, it follows that an animal like the lamprey with a
purely aquatic respiration must either be very sluggish, ora
very perfect respiratory mechanism must be present in order
that it may obtain the needed oxygen from the meager supply
in the water. Inthe lamprey there is a very perfect respira-
tory mechanism. If one considers also the ease and com-
pleteness with which the carbon dioxid is eliminated in
aquatic respiration, and the fact that with the lamprey, from
its habits, only occasionally are great exertion and rapid
movement necessary, as in searching for prey and in spawn-
ing, with the attendant nest building, it will be seen that the
lamprey is very well off for an animal with aquatic respira-

The Lake and Brook Lampreys of New York 463

tion. It may be further stated that when the lamprey has
gorged itself with blood, the first marked change appearing
in the blood taken as food is the reduction of the oxy-hemo-
globin to hemoglobin. Without doubt the oxygen stored in
the hemoglobin by the respiratory activity of its prey is used
for respiratory purposes by the lamprey. As pointed out by
Bert (’70) and others, any thin and highly vascular membrane
may serve as a respiratory membrane. The alimentary canal
of the lamprey answers admirably these conditions, and on
opening the gorged intestine of a lamprey just taken from a
fish, one can trace with the eye alone the gradual transforma-
tion of the oxygenated blood through gradually darkening
shades until the blood is almost black. Examined with the
micro-spectroscope, the transformation can be followed with
great definiteness and by agitating the black blood with air it
reddens and the two characteristic bands of oxy-hemoglobin
reappear. No doubt this use of the oxygen obtained by
another fish is of considerable importance to the lamprey, and
there is realized by it very perfectly the obtaining of ordinary
and gaseous food at the same time.

With the larva, the motions are very energetic for a short
time, then the animal lies on its side panting, as it were, the
respirations are so rapid. In nature, however, only very
rarely is great exertion necessary, as in burying itself in sand
after voluntarily or accidentally becoming free in the water,
also by moving through thesand fora more favorable locality.
Almost the only other muscular activity consists, not in mov-
ing the whole body, but in pumping water into and out of the
broncho-cesophageal chamber for the combined purpose of
respiration and obtaining food.

Respiratory Mechanism and Movements in the Larva.—lf a
larval lamprey is placed in a glass vessel with coarse sand and
a plentiful supply of water it will very soon make a suitable
burrow or canal in which to live. Very frequently the bur-
row will be made in part next to the glass, in which case one
may observe with great definiteness all the respiratory move-
ments, especially ifa magnifier is used. It is seen that in re-
pose the respirations are not far from 100 per minute, sometimes

464 Simon Henry Gage

less, often many more. If the head is exposed and there are
any particles in the water a constant stream is seen to flow into
the mouth. Only when the respirations are very slow is the
stream into the mouth intermittent.

As the burrow is ordinarily open, as shown in Pl. VIII, Fig.
49, some particles of corn starch dropped into it diffuse in the
water and one can then see the direction of the stream from
the particles of starch. Starch is the most satisfactory sub-
stance used with the larval lampreys as they are not irritated
by it. In fact it is taken into the alimentary canal. In case
the water contains minute filaments these will often be drawn
by the stream to the mouth, but the sieve or net work formed
by the oral tentacles catches them and prevents their entrance
into the respiratory chamber. Whenever the oral sieve be-
comes at all clogged by adhering particles, the current is re-
versed and the offending débris washed off most energetically.
If attention is directed to the branchiopores or gill openings,
it is seen that, with every constriction, streams of water shoot
out obliquely caudad. The valves over the branchiopores
(Pl. VIII, Fig. 52, v/.) project outward, but as soon as the
branchial apparatus expands for inspiration the valve closes
the branchiopore so that water does not enter it, and thus all
the water entering the gill cavities must enter through the
mouth. It is seen also that while the stream into the mouth is
practically continuous, its exit through the branchiopores is
intermittent.

If a larva is placed in a dish of water it swims around
somewhat aimlessly but rapidly for a time, but finally rests on
its side. ‘The side on which it lies seems to be a matter of
indifference, and is therefore sometimes the right and some-
times the left. If the water in the vessel is not too deep, the
current made by the jets of water from the branchiopores is
easily demonstrated by putting bits of wood or cork on the
water over the gill-openings. They follow the current almost
directly caudad along the whole length of the larva. If the
position of the larva is noted, and then it is observed again
after 15 or 20 minutes it is seen that it has moved cephalad or
forward due to the recoil or reaction of the jets of water forced

a

The Lake and Brook Lampreys of New York 465

from the gills. The forward movement is not so great, how-
ever, as might be expected from the strength of the backward
current, and the slight retardation due to the friction of the
bottom of the vessel. ‘While the animal is lying on its side,
the current into the mouth is clearly seen by dropping a little
starch into the water. The currents can also be very satisfac-
torily studied by placing the animal in a test-tube or narrow
jar with water and a little corn starch.

Whenever the head of the larval lamprey can be seen in a
good light, an arched, reddish, moving body is visible through
the translucent body wall between the opening of the mouth
and first gill. This is in rhythmical motion toward and away
from the mouth. It is the velwm, composed of two symme-
trically placed, arched curtains which perform the double
function of valve to prevent the water from going out through
the mouth when the branchial apparatus is constricted, and
also of moving by its own musculature something as the dia-
phragm of a mammal and thus alternately increasing and di-
minishing the size of the branchial cavity. If the movement
is carefully watched and compared with the alternate con-
striction and expansion of the branchial apparatus, it is seen
that the expansion of the branchial apparatus and the ce-
phalic or forward movement of the velum coincide, both thus
acting to increase the size of the branchial chamber and there-
fore to draw water into the branchial cavity, that is, both are
imspirators. On the other hand, in expiration the velum is
drawn caudad at the same time that the branchial chamber is
constricted and thus a double diminution of the capacity of
the branchial chamber results and the expiration is complete.
This caudal movement of the velum has also tended to draw
water into the space between the velum and the sieve like
tentacles. This water is drawn into the branchial chamber
immediately upon the expansion of the branchial chamber and
the forward movement of the velum. Owing to the valves
over the branchiopores, the branchial chamber can only be
filled through the mouth, and a current jis drawn into the
mouth both in expiration by the caudally moving velum, and
in inspiration by the expanding branchial chamber, hence it

466 Simon Henry Gage

follows that the current going in at the mouth must be con-
stant, unless the respiratory muvements are exceedingly slow.
The reason why the cephalically moving velum does not force
the water out of the mouth in narrowing the space between
the sieve and the velum is that, as the velum moves forward,
it leaves an equal space behind it and thus aspiration is pro-
duced in the branchial chamber, and as there is nothing to
support the thin mesal edges of the velar folds, they move
laterally and thus make a free passage for the water to the
branchial chamber, so that the action of the velum alone tends
constantly to aspirate the water into the mouth. When the
velum is aided by the expanding branchial chamber in in-
spiration, an increased aspiration is insured and so much the
more is there a constant inflowing current.

By careful experiment on transforming larvee it was found
that they continued to take a constant current into the mouth
even after they were able to attach themselves to the sides of
the vessel containing them by the almost completely devel-
oped sucking disc. Those experimented upon buried them-
selves in the sand and gravel whenever they were given op-
portunity ; it is believed therefore, that until the young lamp-
rey is entirely transformed and swims freely in the water or
becomes attached to a fish, water is inspired through the
mouth as well as through the branchiopores, but, in expiration,
it passes out only through the branchiopores, except when the
branchial apparatus is being cleared of particles taken in with
the respiratory currents. The action of the velum may be
most perfectly shown by thoroughly etherizing a larva and
then carefully removing the ventral body wall between the
velum and tentacles so that the velum may be very clearly
seen. If now the animal is set up endwise in water one can
study very satisfactorily the action of the velar folds. By ad-
ding ether occasionally one can control the rapidity of the re-
spiratory movements so that they may be slow enough for
careful study. For some purposes one may advantageously
remove the entire head cephalad of the velum.

On a frontal section at the level of the branchiopores like
the one shown in Pl. VIII, fig. 52, one can very readily see

The Lake and Brook Lampreys of New York 467

the course of the water in its passage through the branchial
apparatus.

With larve in confinement, whenever the water is in-
sufficiently aerated, the head and sometimes the whole
branchial apparatus is projected from the burrow into the
water. If the water is changed they disappear in a short
time. If the water is not changed or aerated in some way the
larva will leave its burrow entirely and make violent efforts to
escape from the vessel. If one watches the indications he
soon learns about how often to change the water ; in any case
he knows that the water must be aerated or changed -when-
ever the larve give this sign of beginning suffocation.

Respiratory Mechanism in the Adult. — On the change from
the larval to the adult form, the food changes from minute
organisms filtered from the water to blood sucked from other
fishes, and the mode of inspiration must necessarily change ;
for when the lamprey is attached for the purpose of obtain-
ing food or for any other object, there is no possibility of
inspiring water through the mouth. When unattached, how-
ever, water may still be taken into the branchial cavity
through the mouth. For a considerable time during trans-
formation and even when the tongue and the mouth have
nearly assumed the mature condition, if one watches the
particles in the water it is seen that there is still an almost
constant stream flowing into the mouth. Later, however,
although water may enter the mouth in respiration, it does so
rarely, but on the contrary both inspiratory and expiratory
streams must pass in and out of the branchial chamber
through the branchiopores.

As shown in figure 52 of Pl. VIII, the branchiz of the
larva appear to project freely into a common branchial cham-
ber, although there are seven openings on each side from this
chamber. In the adult, on the other hand, there are seven
gill pouches on each side, each pouch being independent ex-
cept for a small opening into the greatly constricted bron-
chus ; and, as stated above, the respiratory streams are both
in and out of each branchiopore so that if the bronchus were
entirely occluded and part of the gill pouches obliterated,

468 Simon Henry Gage

as sometimes happens, the respiration of the animal could
still be carried on. In other words having 14 practically in-
dependent gill pouches renders the liability to suffocation far
less than if a single entrance or exit served for the entire
respiratory supply.

Since in the adult, the inspiratory stream must enter the
same opening from which the expiratory stream emerges,
there must be a different arrangement of valves from that ob-
taining in the larva, where the branchiopores serve only for
the exit of the water. The single valve of the larva is
present in the adult, but it is not wide enough to cover the
entire branchiopore as in the larva; usually it covers only
about the cephalic half (Pl. VIII, fig. 55).

Inspiration is effected largely in both adult and larva by
the elasticity of the cartilaginous branchial basket-work, and
expiration through the constriction of the branchial ap-
paratus by muscular action, thus standing in marked con-
trast to the respiratory actions of mammals where the thoracic
cage must be expanded by active muscular contraction for in-
spiration, while expiration is largely effected by the elasticity of
the respiratory apparatus.

In the case of the lamprey one might think at first that no
valves are necessary in respiration, for if the branchial pouches
are open to the surrounding medium through the branchio-
pores any enlargement of the branchial space would cause the
water to enter, and conversely, any constriction would empty
the branchial sacs. ‘This view is correct, but this mode of
simply drawing water into a sac and expelling it has not ap-
parently answered the requirements of the lamprey, and there —
is present the thin valve (the ectal valve) which covers the en-
tire branchiopore in the larva (fig. 52-55), and in addition a
double valve (ental valve) (fig. 55), which is formed by the
growth and modification of the middle gill lamella of the
caudal half of the branchial sac. This lamella, near the
branchiopore, bifurcates and soon loses its secondary laminze
and each part extends laterad as a firm but flexible membrane
attached to the caudal wall of the branchial sac, one to the
dorsal the other to the ventral edge of the branchiopore and

The Lake and Brook Lampreys of New York 469

also somewhat to the dorsal and ventral parts of the ectal
valve. ‘The other or the cephalic edge of each valve is free.

The action of the valves is as follows: In inspiration, the
two parts of the inner or ental valve turn away from each
other and are pressed toward the cephalic wall of the branchio-
pore across the channel at the edge of the branchial sac, and
the ectal or transverse valve folds over the ental one. By the
expansion of the branchial apparatus, the entrance to the gill
sac has been rendered more direct and the inflowing stream
flows directly into the sac (Fig. 53). In expiration, the
water flows through the branchial lamellee, while around the
edges, z. e., at the dorso- and ventro-lateral edges of the gill
sac there is formed a canal or gutter by the shortening of the
gill lamellae. The free ends of the lamelle are also mem-
branous and curved and aid in making a very complete and
smooth canal. ‘The ental valves at the entrance to the
branchiopore cross this canal and serve as a guide to the in-
spiratory stream, not allowing the water to get into the canal
around the edges of the gill sac, but directing it into the gill
sac itself (Fig. 53). In expiration, however, with the change
in obliquity and the constriction of the gill sac, the water
passes between the branchial lamellze into the canal and meet-
ing the ental valve rotates the two folds of the valve toward
each other and against the caudal wall of the branchiopore,
thus removing the obstruction in the canal and really extend-
ing it by means of the arched valves (Pl. VIII, Fig. 54, 55).
From this arrangement it is seen that two distinct objects are
attained, the water not only bathes the gills but passes be-
tween the lamellez, it is then concentrated in a canal with
smooth sides where the friction is at a minimum ; and in its
exit from the branchial sac in expiration, the valves prevent
the used water from making acircle in the gills, and more im-
portant, they form a very oblique channel which directs the
expiratory stream caudad, thus insuring the animal against
using the same water over and over. In inspiration, on the
other hand, from the direction of the opening, the water enters
at nearly aright angle to the axis of the animal, and thus
fresh or unrespired water is constantly supplied to the gills.
(See figures 51-55, Pl. VIII).

470 Simon Henry Gage

While the branchial pouches are, as stated above, practi-
cally independent, nevertheless they do communicate through
the common bronchus, and occasionally a particle entering
the branchiopore of one side may be seen to emerge from the
opposite branchiopore (Bert, ’67). If one observes the respira-
tion of a lamprey resting upon its side in very shallow water
so that the branchiopores are near the surface, the oblique
streams from the branchiopores are very readily seen. If the
nostril is near the surface of the water a stream is seen to
emerge from it at every expiration. Hence as the nasal sac
is closed caudally, a stream must be drawn in at every inspi-
ration and expelled at every expiration. This movement
simply accompanies respiration and is not for respiratory, but
rather for olfactory purposes. That there is no connection
between the stream forced from the nostril and the respiratory
water may be easily proved by raising the head slightly above
the water. After the first expiration no further jets of water
are sent from the nostril until the head is again submerged,
thus showing that the water enters and emerges from the
same opening.

All the respiratory movements may be artificially imitated
on a lamprey soon after death, if the branchial apparatus
remains expanded. ‘To insure this the lamprey may be cura-
rized ; the branchial apparatus being unconstricted by the
paralyzed muscles, expands by its own elasticity, and the
animal will die in the inspiratory phase. If now the branchial
apparatus is grasped by the hand the expiration may be im-
itated by constricting the apparatus and the streams from the
branchiopores and from the nostril demonstrated. Upon re-
laxing the grasp the branchial apparatus re-expands and re-
fills the gill pouches. By proceeding slowly, one can see
with the greatest accuracy the movement of the branchioporic
valves, and what is obscure, from the rapidity of action in the
living state, becomes clear and intelligible.

THE BLOOD AND ITS FIBRIN, HEMAGLOBIN AND CORPUSCLES.

Asin the higher vertebrates, the blood of the lamprey in
all stages, except the very early embryonic ones is red in color

The Lake and Brook Lampreys of New York 471

and contains both red and white corpuscles. This blood coag-
ulates very quickly, and the fibrin is composed of exceedingly
fine and also coarser filaments. If preparations of lamprey
and human fibrin filaments are compared (Pl. VIII, fig. 44,
45), it will be seen that in both there are centers from which
these filaments seem to radiate, and that in the lamprey, while
there are coarse filaments, the ultimate net-work is almost in-
conceivably fine and that in order to define it well, homo-
geneous immersion objectives are necessary. On the other
hand the net work of filaments in human and other mamma-
lian fibrin is coarse. ‘This condition has been found in all the
mammalian fibrin examined, while the fine network seems to
be characteristic of the cold-blooded animals.

The time required for coagulation in the lamprey is short,
shorter than for mammalian blood but not nearly so short as for
amphibian blood (Gage ’go).

The hemaglobin of the lamprey is exceedingly difficult to
obtain in crystalline form. ‘The only successful efforts so far
have been by using a considerable quantity of blood and add-
ing at the edge of the cover a small amount of a 10 per cent.
aqueous solution of pyrogallic acid. The cover is then sealed
and put in the light inacool place. After several days, in suc-
cessful preparations, crystals appear in beautiful rosettes with
frond-like rays radiating from the center.

The Red and White Blood Corpuscles.—It is to the solid
constituents of the blood that the greatest interest attaches,
and especially to the red-corpuscles ; for ‘‘as the red blood-
corpuscles of the camelide form an exception in the great
mammalian group in being oval instead of circular in outline,
_and, according to Gulliver in not forming distinct rouleaux,
or rolls, so the red corpuscles of the lamprey eels form an ex-
ception in the great non-mammalian group of vertebrates
(birds, reptiles, and fishes) in being 6z-concave and circular,
instead of oval and 67-convex, like those of all other animals
in this great group. ‘The corpuscles also agree with those of
mammals in forming distinct rouleaux. ‘This is most marked
in the brook lamprey and the larva. In the 9 mm. embryo
the corpuscles were often seen in rolls of three or four in the

472 Simon Henry Gage

circulating blood (Pl. VIII, fig. 42, E. F.). Rouleaux have
also been observed in the vessels of a living dog’s mesentery.
A nucleus is present in all the corpuscles, but as it is small and
placed in the thickest part of the corpuscle, it is not apparent
in the perfectly fresh ones, except faintly in some of those of
the 9 mm.embryo. ‘The corpuscles when fresh appear, there-
fore, almost exactly like those of man.’’ So complete is the
resemblance, that skilled observers have frequently been con-
fused, and pronounced fresh preparations of lamprey’s blood
to be mammalian. As seen in the table, however, the num-
ber of the white corpuscles is proportionally very much greater
than in mammalian blood, and the white corpuscles are almost
always smaller than the red ones, thus standing in these two
particulars in marked contrast with mammalian blood. Fur-
thermore ‘‘no element of uncertainty should arise with respect
to them in legal medicine, for (a), the presence of a nucleus
may be readily demonstrated, as it is made apparent by dry-
ing, by acetic acid, and by the reagents most used in exam-
ining blood for medico-legal purposes ; (4), except in the em-
bryo 9-10 mm. long, the corpuscles are nearly twice as large
as those of man. (Compare the accompanying table of meas-
urements). Hence the red blood corpuscles of lamprey eels, in
spite of their bi-concave form and circular outline, really offer
no more difficulty in medical jurisprudence than do the cor-
puscles of any other of the non-mammalian vertebrates.*

“The circular outline of the red blood-corpuscles in both
adult and larval lampreys was discovered by R. Wagner and
the fact published in 1838 (’38). ‘The bi-concave character is
remarked upon by Wagner, Kolliker, and others, but I have
seen no reference to the fact that the corpuscles form distinct
rouleaux like those of mammals. ‘This feature, as in mam-
mals, is lost soon after death.

‘Although the bi-concave character of the corpuscles of
lampreys is as easily demonstrated as in the corpuscles of

* While it is true that the red corpuscles of mammalian embryos and
the developing corpuscles in the adult are nucleated, the size and uni-
formly nucleated condition of the corpuscles of the lamprey would
sufficiently characterize them.

The Lake and Brook Lampreys of New York 473

mammals, it is stated by Gulliver and Gunther that they are
flat or bi-convex, and Gegenbauer in his Comparative Anatomy,
states that the red blood-corpuscles of birds, reptiles, amphibia,
and fishes are bi-convex, no exception being made for the lam-
preys. Parker in his translation of Wiedersheim’s Compara-
tive Anatomy of the Vertebrates, says: ‘In case of the red
corpuscles, the nucleus persists, and the whole cell is bi-con-
vex in all vertebrates below mammals.’ In 1887 wide circula-
tion was given to a statement by Shipley (87), and Thomp-
son (’87), that the red blood-corpuscles of larval lampreys
were oval in outline, like the rest of the non-mammalian ver-
tebrates.”’

And Thompson further adds : ‘‘ The noteworthy point now
is, that myxine possesses red corpuscles similar to those, not
of the adult, but of the larval lamprey, which in many ways
it resembles otherwise.’’ On consulting the original article
by Shipley (’87), the statement is found to be: * The blood
corpuscles are of only one kind, large oval disc-like structures,
with a well-marked nucleus.’’ The size of the embryo is
not given, but it was in the stage before the white blood-cor-
puscles appear. As all observers have noted the tendency of
the red corpuscles to become deformed, one can readily under-
stand that, if the form were observed in sections, from mutual
compression the corpuscles would not remain of circular form.
If Dr. Shipley examined these corpuscles in the serum of the
larva and in the living condition, and they were found oval
instead of circular, the fact would be exceedingly interesting
and perhaps suggestive. One would hardly expect to find
embryonic blood-corpuscles oval, for even in animals in which
the red corpuscles of the adult possess an extreme elliptical
form the embryonic ones are either circular or approximately
so (Kolliker ’84. Milne-Edwards).

‘That the red blood-corpuscles of both the adult and larval
lampreys are circular, bi-concave, nucleated discs, as here de-
scribed and figured, was repeatedly demonstrated in larvee
from g to 142 mm. long, and in numerous adults. In every
specimen examined all the corpuscles not irregular were cir-
cular in outline. ‘To make sure that this appearance was not

474 Simon fenry Gage

due to reagents, the corpuscles were examined in the serum of
the blood, without the addition of any reagent whatever, and
to avoid any possible error on account of the small amount of
blood in the 9 mm. embryo, the circulating blood was exam-
ined. All the examinations were made with a 2 mm. apo-
chromatic objective and an ocular x 12’’ (Gage ’88).

Table showing the diameter and thickness of the red and of the white
blood-corpuscles of the lamprey in the adult and larval condition ;
also the relative number of red and white corpuscles, and the num-
ber of red corpuscles in a cubic millimeter of blood.

reineeieset aie 6 ae ¢ |No. of red cor-
F Y | Rati : :
ee Thick: | 9G & [white to rea) Puscies in a
Maxi-| Mini- | Aver- | r Ses corpuscles. | jnitlimeter.
mum,.|} mum.| age. vaio)

Lake lam- Male, 1 : 20) Male, 391,333
prey (June),|16.16/)10.1 “4j14.2 “| 5.05|1:2.8 |Fem., 1:15|Fem. 334,666
Lake lam-
prey (Oct.),|16.25|10.62/4/13.9 #4) 5.0 “4/1: 2.78|Male, 1:17|Male,513,280
Brook lam-
prey (May),|I5.15/10.1 “|13. | 5.02¢/1:2.59| 1:95 500, coo
Larval lam-
prey, 142 1:24
mm. long, |15.65/)12.12//13.4 4) 3.48u|1:3.8 Wee 712,950
Embryolam-
prey, 9mm. Not deter-
long, 8. ml 7. 4/7.448u| 1.96u/1:3.8 i) 2 1) mined.
Larval lam- White.
prey, 58
mm. long, 5.56
Lake lam-
prey (Apr.), 7.8 bu

The blood for measurement and counting was taken from
the heart of an animal just killed or from a pithing wound,
and mounted without the addition of any liquid. The cover-
glass was supported by a hair and sealed with castor oil.
Only undistorted corpuscles were measured. The averages
were obtained from twenty-five measurements in each case.
All measurements were made with a ;); or 7; homogeneous
objective, and a Jackson ocular micrometer, the valuation of
which was determined by using a Rogers’ standard stage mi-
crometer.

The Lake and Brook Lampreys of New York 475

In a larva 73 mm. long, the average diameter was 12.44"—
that is, 0.96 smaller than in the larva of 142 min. given in
the table. Gulliver (62-75, p. 845) states that there is little
difference between the blood-corpuscles of Petromyzon planert,
P. fluviatilis, and Ammocetes branchialis [the larval form] ;
that one description may serve for all three of them ; and gives
the following measurements: Diameter of the red poraueeles
11.9 #; thickness, 4.09 #; diameter of nucleus, 3.96 w. Kol-
liker gives 11.3 as the size, not mentioning the species or
the age. Welcker (’63), gives 15 » as the average size of the
red corpuscles of Petromyzon marinus, with a maximum of
16 wand a minimum of 13.4 #. Thickness of the corpuscles,
3. For the larva the average is 11.7 », with a maximum of
12.4 #and a minimum of 10.9 ». Thompson (’ 87), gives the |
size of the red corpuscles of Petromyzon marinus as 13 » to
14 p. Welcker gives the number of red corpuscles in a cubic
millimetre of the blood of P. marinus as 133,000.

In my own studies, which have extended through several
years and have considered specimens at various seasons, the
statements of Gulliver are not wholly verified. On the other
hand, as shown in the table, the red corpuscles increase in size
with the increase in size of the whole animal. This is most
marked in larval life. After nearly reaching their full growth as
larvze the increase of the red corpuscles to the fully adult condi-
tion is only about one micron (1 »), while between the 9 mm.
and the 73 mm. larva there is a difference of 5 m. but only
about 1 p. between the 73 mm. larva and the one 142 mm.
long. This fact of the growth in size of the corpuscles
with the growth in the size of the body is again in marked
contrast with what is known of the mammalian red corpuscles,
which in the new born and the fully matured differ very little
in size.

The relative number of red and white corpuscles has been
determined at various seasons of the year, and while the num-
ber of white ones is greater in some specimens than in others,
the season does not seem to affect this ratio very markedly.
In general, the lake lamprey has a greater relative number of
white ones than the brook lamprey, and in the Jarva they are
more numerous than in the adult. In no case was there seen

476 Simon Henry Gage

the proportion given by Thompson, z. e., three or four white
ones to one red one. In my own observations the red ones
were always in excess of the white ones. (See table above).

The amceboid movements of the white ones are striking and
vigorous in both larva and adult, but as arule the motion does
not begin immediately after the preparation is made, It is
usually at its greatest about half an hour after the blood is
obtained.

SUMMARY AND GENERAL CONCLUSION.

1. Two species of lampreys inhabit the chain of lakes in
' western New York.

2. One, the brook lamprey (Petromyzon or Ammocetes
branchialis) is small in size, few in numbers and short-lived,
in the adult stage. It is not known in North America outside
the Mississippi Valley except in the Cayuga Lake basin. It
is probably widely distributed, but from its small numbers and
inconspicuous coloring, it has been overlooked (Plate IV, pp.
436, 452).

3. The other, the lake lamprey Petromyzon unicolor or dor-
satus), is of large size, isin great numbers and lives a para-
sitic life in the lakes for a period of two to three and one-half
years, and perhaps longer (Plate I, III, pp. 431, 445, 452).

4. The lake lamprey from the structure and arrangement of
its teeth is hardly to be distinguished from the true anadro-
mous sea lamprey, but judged by the physiological test of nat-
ural interbreeding it must be considered as specifically dis-
tinct (Plate VI, p..426).

5. Both species have a larval stage and a metamorphosis at
the end of from two to four years. Thus agreeing with the
Petromyzontidze wherever thoroughly studied (Plate III, IV,
VI, VIII, pp. 449, 452).

6. The proportions of parts of the body with the two sexes
of the lake lamprey, are very unlike and mutually interchange
between the ordinary non-breeding and the breeding season.
(See Table and p. 431).

7. In both species there are striking atrophies and hyper-
trophies at the spawning season (Plate III, IV, VII, p. 438).

8. Both species construct similar nests for the deposit and

ee

The Lake and Brook Lamprevs of New York — 477

protection of the ova. The larve hatch in these nests, re-
main there till they are about 12 to 15 millimeters in length,
then they seek a sand bank in the concavity of the stream.
‘In this bank they remain until fully transformed and supplied
with horny teeth. They then leave the sandy covering and
lead a roving, parasitic life in the open waters of the lake
(Plate VII, VIII, pp. 441, 449).

g. In its larval life the lamprey is not injurious to man, but
aids him by serving as bait for food fishes (p. 457).

10. During adult life the lamprey is highly injurious, as it
preys upon food fishes. The lake lamprey is the more in-
jurious from its larger size, greater numbers and longer para-
sitic life (pp. 445, 457).

11. The lakes could be easily freed from lampreys, by catch-
ing and destroying them when they are on their way to the
spawning grounds up the lake inlets (p. 461).

12. The respiratory mechanism of the lamprey is very per-
fect at all stages. From the perfection and arrangement of
the branchiai valves, the expired water is not re-inspired
Relate Vit. pp: 463; 467):

13. The blood-corpuscles are of two kinds, white and red as
in most other vertebrates.

14. The white blood-corpuscles are relatively more numer-
ous than in mammalian blood; they are mostly smaller than
the red blood-corpuscles and exhibit active amceboid move-
ments (Plate V.LEl.p? 471):

15. The red blood-corpuscles are bi-concave, circular discs
as with mammalian blood-corpuscles, and like the mamma-
lian red blood-corpuscles those of the lamprey arrange them-
selves in rolls or rouleaux, (Plate VIII, p. 472).

It is assumed throughout this paper that the lake lamprey is
a land-locked species which is a recent offshoot from the true
anadromous sealamprey. But forthe very striking similarity,
a similarity amounting almost to specific identity with the sea
lamprey, one might be strongly inclined to the belief that the
lake lamprey is an original product of the lake waters and
has only a remote relationship with the sea lamprey through
some primitive and common ancestor. On the other hand
it might be urged that as there is free communication between

478 Stmou Henry Gage

the lakes and the ocean through the St. Lawrence River,
there is no occasion to consider the lake lamprey as a land-
locked form at all.*

While it is true that the natural obstacles are not such as
to prevent the immature lampreys from passing to the ocean
and then returning when mature to deposit their spawn, the
distance inland is greater than undoubted sea lampreys have
ever been known to pass; certainly none have ever been
found in Cayuga and Seneca lakes by the writer, and from
information obtainable from others none have been seen in
any of the lakes or in Lake Ontario.t

The final and definite proof that the lake lampreys remain
permanently in the lakes and do not go to the ocean at any
time, has been abundantly obtained during the past 18 years
by the capture of examples of the adult form of all sizes in
the waters of the Jake during every month of the year, while
the true anadromous forms are found in the inland waters
they are known to inhabit, only when very small and when
spawning.

As to a reasonable hypothesis for the presence of these ios-
lated or land-locked lampreys : It is recognized by all modern
geologists and physical geographers that the present contour
of the country and the details of the topography of the greater
and lesser lake basins with their water courses and ridges are,
geologically speaking, only of recent date. By glancing
again at the small topographical map (Pl. II) it can readily
be seen that during the glacial epoch when the basins of the
St. Lawrence and of the lakes were filled with ice, the water
from the melting ice accumulated and finally passed the
low elevation south of the lake basin and found its way to the
Susquehanna River. Later, as the ice sheet receded, the out-
let was through the Mohawk into the Hudson River. Finally

* The common eel (Anguilla rostrata) is also abundant in the lakes,
As it has been determined by recent investigations that the common
eel goes to the ocean or to brackish water to spawn and the young re-
turn to fresh water to mature, it will be seen that the passage to and
from the ocean is not insuperable.

+ I wish to express my indebtedness to the State Game and Fish Pro-
tectors who so fully and courteously answered the questions concerning
the lampreys of their respective districts.

ae

The Lake and Brook Lampreys of New York 479

as the ice melted the superfluous water of all the lakes gradu-
ally found an exit through the St. Lawrence basin as it had
done in pre-glacial times.

The application of these geological or topographical
changes would have the following bearing upon the special
subject of this paper. At the present time in the Susquehan-
na River, only a few miles to the south of Cayuga Lake, the
large sea lampreys are found in the summer or spawning
season and the transforming ones in the autumn, and larvze
during the entire year, thus showing that even at the present
day the large sea lamprey uses the Susquehanna for a spawn-
ing ground. The same is true of the Hudson River.

Now it is believed that while the lakes poured their super-
fluous waters southward into the Susquehanna River that the
large sea lampreys frequented the lake and its tributaries and
found suitable spawning grounds. As the glacier receded
and the streams draining the lake into the Susquehanna
became shallower and more difficult to ascend and descend,
the lakes were less and less and finally no more visited by
the spawning lampreys; and some of the newly transformed
ones, finding abundant food in the common fishes which
swarmed in the waters, remained and matured in the lakes,
and spawned in its tributaries thus completing the entire life-
cycle in fresh water.

It is also possible that as the water courses to the Susque-
hanna decreased and those to the Mohawk and Hudson in-
creased, the lampreys entered and lett the lake through those
streams, but ultimately the same result would follow and the
forms become isolated in the lakes.

If it is granted that the presence of the lake lampreys can be
satisfactorily accounted for in the way described, it is not dif-
ficult to conceive of the diminiution in size and perhaps also
of the other modifications, as the great increase of the dorsal
ridge in the male ; for it is within human observation that sea
animals that have been artificially or naturally isolated from
the ocean gradually decrease in size, and that special features
may become accentuated or intensified.

ITHACA, N. Y.
September, 1893.

BIBLIOGRAPHY.

The literature relating to the Marsipobranchii is so extensive that no
attempt has been made to give a complete list; it includes some late
papers bearing on the subject of this investigation, and a few important
works in which the bibliography is especially complete. For references
see also: Engelmann and Carus, Bibliotheca Zoologica III, (1860) pp.
1030-1031.

Papers and works are arranged alphabetically according to authors,
and the last two figures of the year of publication are given at the left.

*50. AGassiz, L. On the Petromyzontidee and their embryonic de-
velopment and place in the natural history system. Edinb. New
Philos. Jour., XLIX, pp. 242-246.

’8X. BALFour, F. M. A treatise on comparative embryology. 8°, two
vols. London.

’88. BEARD, J. The teeth of myxinoid fishes. Nature XXXVII, p.
499. Also the nature of the teeth of the marsipobranch fishes,
Zool. Jahrb. Spengel. Abth. f. Anat. III, 4 Heft, pp. 727-752. Also
the parietal eye of the cyclostome fishes. Quart. Jour. Micr. Sci.
XXIX, pp. 55-73-

Notes on lampreys and hags. Anat. Anz., VIII, pp. 59-60.

Ova as well as sperm mother-cells in the testis of a brook lamprey.

’*80-’8x. BENECKE, B. Fische, Fischerei und Fischzuclit in Ost- und
West-preussen. Mit zahlreichen Abbildungen. 8°, pp. 514. Ko-
nigsberg.

°@7. BERT, P. Note sur quelques points de la physiologie de la
lamproie. Ann. des Sci. Nat., V Ser. t. vii, pp. 39-40. Notes on the
respiration of the lamprey.

93

70. Lecons sur la physiologie comparée de la respiration, pro-

fessées au muséum d’histoire naturelle. 8°, Paris.

°88 Boum, A. A. Uber Reifung und Befruchtung des Eies von Pe-
tromyzon planert. Arch. f. mikr. Anat., XXXII, pp. 613-670.
Gives a history of the development of the ovary and ova.

’gI. Buyor, P. Contribution a l'étude de la métamorphose de 1 Am-
mocetes branchialis en Petromyzon Planeri. Revue Biologique
du Nord de la France, III, 97 pages. The main thesis of this
paper is that during the metamorphosis from the larval to the adult
condition the tissues return to an embryonic condition and that the
adult tissues are re-formations from a practically embryonic state.

’97. CALBERLA, E. Zur Entwicklung des Medullarrohres und der
Chords dorsalis der Teleostier und der Petromyzonten. Morph.
Jahrb. III, pp. 226-270.

°@5. Coucnu, J. A history of the fishes of the British Islands. Four
volumes. Lampreys in Vol. IV, pp. 383-401.

’°86. CUNNINGHAM, J. T. Dr. Dohrn’s inquiries into the evolution
of organs in the Chordata. Quart. Jour. Micr. Sci., XX VII, pp. 265-
284. Discusses the ten papers of Dohrn ‘‘Urgeschichte des Wirbel-
thier-korpers’’ published from 1882 to 1885, in which the mor-
phology of the Marsipobranchii is considered at considerable
length.

The Lake and Brook Lampreys of New York 481

‘976. Ewart, J. C. Note on the abdominal pores and urogenital
sinus of the lamprey. Jour. Anat. and Phys., X, pp. 488-493.

On vascular peri-branchial spaces in the lamprey. Same,
XII, pp. 232-236.

‘975. FURBRINGER, P. Untersuchungen zur vergleichenden Anatomie
der Muskulatur des Kopfskelets der Cyclostomen. Jenaische Zeit-
schrift, IX, 93 pages.

'84. GaGE, S. H. On the application of photography to the produc-
tion of natural ae figures. Science, III, pp. 443-444.

86. — and S. MEEK. The lampreys of Cayuga Lake. Proc.
Amer. Assoc. rs Sci., XX XV, p. 269. Abstract, giving findings
up to that date.

88. The form and size of the red blood corpuscles of the adult
and larval lamprey eels of Cayuga Lake. Proc. Amer. Soc. Mic-
roscopists, X, pp. 77-83. Also the red blood corpuscles of lamprey
eels in relation to jurisprudence. N. Y. Med. Jour., XLVIII, pp.
149-150. In these papers it is shown that the red corpuscles form
in rolls and that they increase in size with the growth of the
animal. An annotated bibliography of twenty papers and works
acconipanies the first.

‘90. Comparison of the fibrin filaments of blood and lymph in
mammalia and amphibia, with methods of preparation. Assoc.
Amer. Anatomists, history, constitution, membership, and the titles
and the abstracts of papers for the years 1888-1890, pp. 25-26.

Notes on the physiology and structural changes in Cayuga
Lake lampreys. Proc. Amer. Assoc. Adv. Sci., XL, p. 322.

92. The comparative physiology of respiration. Proc. Amer.
Assoc. Adv. Sci., XLI, pp. 183-196; Amer. Naturalist, XXVI, pp.
817-832 ; Nature, XLVI, pp. 598- 601. Comparison of zerial and
aquatic respiration and special consideration of combined aquatic
and zerial respiration.

’84. GoopDE, G. BRown. The fisheries and fishery industries of the
United States. Prepared through the co-operation of the commis-
sioner of fisheries and the superintendent of the tenth census, by
George Brown Goode, assistant director of the U. S. National
Museum and a staff of 20 associates. Section I, Natural history of
useful acquatic animals, Washington, Government printing office,
pp. 677-651. An excellent account of the state of knowledge at
that time. In the same volume, pp. 630-656, is a complete account
of the natural history of the common eel (Anguilla).

’g99. GOTTE, A. Entwickelungsgeschichte des Flussneunauges (Pe-
tromyzon fluviatilis). Erster Theil. 4°, p.95. Hamburg u. Leipzig.

°53. GUNTHER, A. Die Fische des Neckars untersucht und _be-
schrieben. Pp. 133-136, on lampreys. It is stated that their food
consists of ‘‘worms, insects, etc.’’

Catalogue of the fishes in the British Museum, Vol. VIII.
Pp. 499-509 devoted to the Petromyzontide. It is stated that the
larvee are without teeth and “with a continuous vertical fin.’’

So. The study of fishes; also, Ichthyology in the Encyc.
Brit. Vol. XII.

’67. GRENACHER, H. Beitrage zur nahern Kentniss der Musculatur
der Cyclostomen und Leptocardier. Zeit. wiss. Zool., XVII, pp.
577-597-

78.

<)> @

70.

482 Simon Henry Gage

'@2-'75. GULLIVER, G. On the red blood-corpuscles of vertebrates.
Proceedings Zoological Society, 1862, p. 99; 1870, p. 844; 1875,
p- 474. Gives an excellent account of the blood-corpuscles in all
groups of vertebrates (1870, p. 844).

’g2. Hatra, S. On the formation of the germinal layers in Petromy-
zon. ‘The Journal of the College of Science, Imperial University of
Japan. V, pp. 129-147.

*g2. HERTWIG-MARK. Text-book of the embryology of man and
mammals. 8°, pp. 670. London and New York.

’46. HEwson, W. Works of, edited by Gulliver. pp. lvi+360. Lon-
don, printed for the Sydenham society.

’gi. Howes, G. B. On the affinities, interrelationships and systematic
position of the Marispobranchii. Proc. and Trans. of the Liver-
pool Biological Society, VI, pp. 122-147. An excellent summary
of the latest views on the morphology and relationships of the
marsipobranchs with table indicating structural and phylogenetic
relationships.

976. Huxley, T. H. On the nature of the cranio-facial apparatus of
Petromyzon. Jour. Anat. and Phys., X, pp. 412-429. Howes (’91)
says of this paper: ‘‘ All recent enquiry into the morphology of the
cranio-facial apparatus of the Marsipobranchs finds its focus in
Huxley’s monograph in which the presence of true jaws was first
demonstrated and the complex apparatus of the Petromyzontidze
was brought into harmony with that of the higher gnathostomata.”’

"46. Jones, W. The blood corpuscle in its different phases of develop-
meit in the animal series. Phil. Trans., 1846, pp. 63-101. On p.
66 he says the red corpuscles of the lamprey are circular at all
stages of development.

’82. JORDAN, D. S. and GILBERT, C. H. Synopsis of the fishes of
North America. Bulletin of the U. S. National Museum, No. 16,
pp. 1018. Good references to systematic literature.

and ForpbICcCE, M. W. A review of the North Ameri-
can Species of Petromyzontidee, with an additional note on
the Lampreys of Cayuga Lake, by S. E. Meek. Reprint, pp. 279-
296. (Place and periodical in which published not indicated on
reprint), On p. 284 the authors say of the lake lamprey: ‘‘ The
characters assumed to distinguish this form: from the true marinus
are, however, more or less inconstant and not of specific value.’’
Very full references to systematic literature.

°87. JuLIN, C. Recherches sur l’anatomie de l’ammoccetes. Bulletin
scientifique du department du nord. 2dser., X, 42 pp.

’'9O. K2NSCHE, C.C. Beitrage zur Kentniss der Metamorphose des
Ammocetes branchialis in Petromyzon. Schneider’s Zoologische
Beitrage. Band II, Heft II, pp. 219-250. ‘The author believes that
the oral tentacles disappear, except the ventral median one which is
transformed into the adult tongue.

°84. KOLLIKER, A. Grundriss der Entwickelungsgeschichte. 8°, pp.
viiit+454. Leipzig. On p. 63 it is stated that the red blood cor-
puscles of the chick are, in the course of development, at first cir-
cular.

’9O. KupFFER, C. Die Entwickelung von fetromyzon Planert.
Arch. f, mikr Anat., XXXV, pp. 469-558.

85.

The Lake and Brook Lampreys of New York 483

'$2. LEeGouIS, P. S. Recherchessur le pancréas des cyclostomes et sur
le foie dénué de canal excréteur du Petromyzon marinus. Compt.
Rend. Acad. des Sci. Paris, XCV, pp. 305-308.

'73. LANGERHANS, P. Untersuchungen uber Petromyzon planert. 8°,
114 pages. Freiburg. The histology of many of the organs is
given.

’g5. Maver. Analecten fiir vergleichende Anatomie, I Theil, p. 60.
This has not been seen, but it isreferred to by Schneider and others
for observations upon respiration and the respiratory organs.

’$8. MEEK, S. E. Notes on the fishes of Cayuga Lake basin. Annals
of the New York Acad. of Sci., IV, pp. 297-316. See also Gage and
Meek above (’86).

'S9. —— Note on Ammocetes branchialis. Amer. Nat. XXIII, pp.
640-642.

’57~58. MILNE-EDWARDS. Lecons sur la physiologie et l’anatomie
de l’homme et des animaux. 8°, 14 vols., Paris 1857-1880. Very
excellent bibliography in volume 2, (1857) pp. 246-247, 256-257 and
in volume 3 (1858) p. 370.

’7x. MILNER, J. W. Report of the fisheries of the Great Lakes; the
result of inquiries prosecuted in 1871-1872. In the report of the
United States Fish Commissioner for 1872-1873. In discussing the
sturgeon fishery Mr. Milner says they frequently have raw sores
upon them due to the lampreys. He thinks the lampreys eat the
slime of the sturgeon.

’g2. Minot, C.S. Human Embryology. 8°, pp. 815. New York.

56. Mier, A. Ueber die Entwickelung der Neunaugen; ein vorlau-
figer Bericht. Archiv f. Anatomie, Physiologie und wissentschaft-
liche Medicin (Miiller’s Archiv)., 1856, pp. 323-339. First scienti-
fic account of the transformation of larval lampreys into adult Pe-
tromyzon. Up to this time the larvee had been placed in a separate
geuus (Ammocetes branchialis). But little has been added to
Miiller’s account of the more obvious changes from the egg to the
adult lamprey. He reported the presence of an 8th branchiopore in
the embryo (‘‘ Am Halse befinden sich 8 Visceralspalten, deren vor-
derste, schon durch ihre Richtung verschieden, sich bald wieder
schliesst’’'. The discovery of an 8th gill opening in the embryo
is ascribed to Huxley by Shipley (’87, p. 349).

43. MULLER, J. Untersuchungen tiber die Eingeweide der Fische.
Abhl. d. kgl. Akad. der Wissensch. zu Berlin, 1843, pp. 109-170.
Announces (p. 119) that the red blood corpuscles are elliptical in
Myxine.

’gO. NESTLER, K. Beitrége zur Anatomie und Entwickelungsges-
chichte von Petromyzon Planeri. Zool. Anz., XIII, pp. II-12;
Arch. f. Naturgeschichte, 1890; Ann. Mag. Nat. Hist. ser. 6, Vol. v,
pp. 262-263. He believes that the cesophagus of the adult develops
from a solid cord along the ventral side of the dorsal aorta in the
larva. Compare Schneider, (’79, p. 94).

’So0. NussBAUM, M. Zur Differenzirung des Geschlechts in Thierreich.
Arch. f. mikr. Anat. XVIII, pp. 1-121. As eggs of Petromyzon are
all at the same stage of development, the author thinks the lam-
preys die after spawning (p. 47) thus agreeing with A. Muller (’56,
Pp: 334).

484 Simon Henry Gage

’OI. OWEN, R. Comparative Anatomy and Physiology of vertebrates.
8°, 3 vols., London, 1861-1868. Vol. I., 1861.

’82-83. PARKER, W.K. On theskeleton of the marsipobranch fishes,
part 2, Petromyzon. Proc. Roy. Soc., 1882, pp. 439-443; 1883, pp.
I-3; Philos. Trans. Roy. Soc. part 2, 1883, pp. 373-457.

’84. PARKER, T.J. A course of instruction in Zootomy, Vertebrata.
8°, pp. 397- London and New York. Good account of the anatomy
of the adult lamprey.

’88. ROLLESTON, G. Forms of animal life, a manual of comparative
anatomy with descriptions of selected types. Second edition, re-
vised and enlarged by H. W. Jackson. pp. xxxii +937. Oxford.
‘“At the metamorphosis the tubular structure [of the liver] is lost ;
fat appears in the cells; the gall-bladder, and bile duct are ab-
SOLDERS Hos, . 1's The pancreas is perhaps represented in the lampreys
by an acinous gland opening into the widened commencement of
the mid-gut on the left side’’ (p. 435).

°7Q. SCHNEIDER, A. Beitrage zur vergleichenden Anatomie und Ent-
wicklungsgeschichte der Wirbelthiere. 4°, pp. 164. Berlin. Dis-
cusses the habits, structure and transformations of lampreys.

’8X. ScoTT, W.B. Beitrage zur Entwickelungsgeschichte der Petromy-
zonten. Morph. Jahrb., VII, pp. ro1-172.

’87. —— Development of Petromyzon. Jour. Morph., I. pp. 253-
310. The myel is rounded in the embryo, flattens before adult life.

’86. SEELEY, H.G. The fresh water fishes of Europe ; history of their
genera, species, structure, habits and distribution. 8°, pp. 444; Lon-
don, Paris, New York and Melbourne.

’87. SHIPLEY,.A. E. On some points in the development of Petromy-
zon fluviatilis. Quar. Jour. Micr. Sci., XXVII, pp. 325-370. On
p- 343 hesays that in the embryo there is but one form of blood-
corpuscle and that this is ‘‘ large, oval and disc like.’’

’87. THOMPSON, D’ARCY, W. On the blood corpuscles of the Cyclos-
tomata. Ann. and Mag. Nat. Hist., Ser. V, Vol. XX, pp. 231-233 ;
Anat. Anz., II, pp. 630-632.

’38. WAGNER, R. Beitrage zur vergleichenden Physiologie, Vol. II,
1838. Nachtrage zur vergleich. Physiol. des Blutes, p. 13. First
announcement that the red blood corpuscles of larval and adult
lampreys are circular and biconcave.

’@3. WELCKER, H. Grosse Zahl, Volum, Oberflache und Farbe der

Blutkorperchen bei Menschen und bei Thiere. Zeit. f. ratl. Med.,
3d Reihe, XX, pp. 257-307.

EXPLANATION OF THE PLATES.

Plates I, III, IV, and V are from photographs of fresh or preserved
specimens. The specimens in most cases were immersed in water or
alcohol, and photographed with a vertical camera. Plates VI, VII, and
VIII were drawn by Mrs. Gage from photographs or from the object by
the aid of a camera lucida.

PRADH I. RIGS I-25

A pair of lake lampreys about 33 centimeters long, from the same
nest ; obtained June 9, 1893. At the head of the article.

Fic. 1. Male lake lamprey showing dorsal ridge and the approxima-
tion of the two dorsal fins. This specimen weighed Ior grams.

Fic. 2. Female lake lamprey. The dorsal fins are not connected, and
no dorsal ridge is present, but the anal notch is marked. This female
had almost completed spawning, and hence appears slender. Compare
with the sea lamprey full of eggs (Fig. 17, Pl. V).

The stone to which the specimen is attached weighed 199 grams, the
specimen only 72 grams. While this pair were in the nest and under
observation the female was seen to drag this stone down the stream for
a considerable distance.

PLATE II. FIG. 3-4.

Map of the head of Cayuga Lake, showing the surrounding country
and the streams flowing into the lake. (From W. R. Dudley’s Cayuga
Flora.) The squares on the map are kilometers and the zero point is
the University Signal Station (U. S. S.) point of reference, a point on
the University campus, whose latitude and longitude have been deter-
mined with great accuracy by the Department of Civil Engineering.
Fig. 4, in the upper right hand corner, is a topographical map of the
lake basin designed especially to show the lakes and their outlet through
the Oswego River, the water-shed around the basin is indicated by 1n-
terrupted lines, and also the water courses draining the elevation sur-
rounding the lake basin. It is to be noted that the Susquehanna River
with its tributaries is the most important of these.

There is an important ridge between Lake Ontario and the interior
lake basin, and this elevation is drained by numerous small streams
flowing northward into Lake Ontario. It is to be especially noticed
also that this elevation is broken through by the Oswego River.

L. Wake; R. River; Cud. Canandaigua Lake; Crkd. Crooked or
Keuka Lake; Owsc. Owasco Lake; Sft/s. Skaneateles Lake; Ond.
Onondaga Lake. Several small lakes have been omitted. x

PLATE II. FIG. 5-10.
Figures to represent the relations of the two dorsal fins in the male

lake lamprey in and out of the spawning season, the female in the
spawning season, and two larvee of very different sizes.

486 Simon Henry Gage

Fic. 5. (About 4d natural size). The first lake lamprey obtained.
The branchial apparatus is in the inspiratory phase, and therefore wide-
ly expanded. The dorsal ridge, so characteristic of the male lake lam-
prey, is more than usually prominent in this specimen ; the fusion of
the two dorsal fins is also shown.

Fic. 6. (4 natural size). Part of a male lake lamprey caught in De-
cember, to show the decided interval between the two dorsal fins; also
to show the non-appearance of the genital papilla out of the breeding
season. The myotomes are also very clearly indicated.

Fic. 7. (¢ natural size). Segment of a male lake lamprey in the
spawning season, to show that the two dorsal fins appear continuous or
simply notched during this season. The genital papilla is also very
prominent at this period.

Fic. 8. (4 natural size). Caudal end of a female lake lamprey in the
spawning season to show the separation of the dorsal fins even in the
breeding season in the female ; the notched appearance of the vent and
the fin-like fold extending to the caudal fin.

Fic. 9. (Natural size), The caudal half of a larval lamprey 150 milli-
meters in length, to show the separation of the two dorsal fins. The
myotomies are also well shown in part of the length.

Fic. to. (Natural size). A small larval lamprey to show the separa-
tion of the dorsal fins even in specimens of this size. In specimens
only 40 mm. long, there is a notch in the fin showing plainly where the
interval is to be.

PLATE Iv. FIG. 11-15.

Brook Lampreys and a larva just before transformation.

Fic. 11-12. (Natural size). A pair of brook lampreys taken at the
spaw.ting season. Photographed under water with a vertical camera.
The male (Fig. 11), has a somewhat prominent genital papilla. In the
female (Fig. 12), there is present a marked anal fin-like fold, and the
caudal part of the abdomen is full of eggs. In both male and female
there is a notch, but no interval between the two dorsal fins, and in the
female the cephalic part of the second dorsal is edematous. Compare
figure 14.

Fic. 13. (Natural size). The caudal part of a brook lamprey that
had just transformed. The specimen was taken in October, and meas-
ured 200 millimeters in length. The two dorsals are widely separated,
but appear to be connected by a very low ridge.

Fic. 14. (Natural size). An oblique view of the caudal part of a fe-
male brook lamprey especially to show the edematous second dorsal
fin, filling, almost completely, the notch between the two dorsals. Near
the end of the spawning season this edema is frequently infiltrated with
blood so that the females are marked by a bright scarlet spot.

Fic. 15. (Reduced ,;Gth). Larval lamprey, 190 millimeters in length,
to show the size the larvae may reach before transformation. This one
is longer than the adult brook lampreys here figured, but not quite so
long as the one from which figure 13 was taken.

PLATE V. FIG. 16-18.

A pair of sea lampreys, from Lawrence, Mass., running up the Merri-
mac River tospawn. Photographed under water after preservation in
Miiller’s fluid.

— a Oe

The Lake and Brook Lampreys of New York 487

Fic. 16. (About id natural size). A male sea lamprey 575 millime-
ters long at the spawning season. The dorsal ridge is very low and the
two dorsals are separated by a considerable interval. The eyes were
sunken and obscured during the preservation.

Fic. 17. (Somewhat less than }d natural size.) A female sea lamprey
645 millimeters in length at the spawning season. The eggs had not
yet been shed, hence the fullness of the abdomen. Opposite the first
dorsal fin the roundish white mark indicates the place where another
lamprey had attached itself to this one. The incompleteness of the
tail on the ventral margin is due to some accident either before or after
death.

Fic. 18. (Natural size). Ventral view of the head of the male lam-
prey shown entire in figure 16. To show the arrangement of the sen-
sory or nerve papillae (see Fig. 20 and 51, Pl. VI and VIII). The cir-
cumoral fringe or plaiting and the lateral closure of the mouth are also
shown. The oblique direction of the branchiopores is shown, especially
on one side.

PLATE VI. FIG. 19-26.

The mouth and its appendages in the adult, transforming and larval
stages. The figures of the adult mouths are from photographs of the
fresh specimens made during the spawning season. The other figures
are from camera lucida drawings of preserved specimens. The magni-
fication of each is given immediately after the number of the figure.

FIG. 19. (X 2). The ventral aspect of the head of a lake lamprey es-
pecially to show the arrangement and number of the teeth. By com-
paring the teeth of the supra- and infra-oral laminae with those of the
annular cartilage from another specimen (Fig. 24), it will be seen that
there are 9 infra-oral teeth on the annular cartilage, and 8 in Fig. 19.
The range is from 6 to 10, the most common number being 7 or 8. In
rare cases the two supra-oral teeth are fused, thus giving the appear-
ance of a single median tooth.

i. | Hye.

S. O. Sense organs or nerve papillae. For those on the lateral and
dorsal aspect of the body, compare figure 51 of plate viii.

FIG. 20. (X 2). Ventral aspect of the head of a sea lamprey from
Lawrence, Mass., to show the oral disc with its concentric rows of
teeth, the supra- and infra-oral teeth and the teeth of the tongue. Com-
pare figure 25.

S. O. Sensory organs or nerve papillae.

Fic 20, A-E. (X 5). Enlarged papillae from the circumoral fringe,
to show their size and form at different parts of the circumference. In
the lake lamprey the papillae are almost exactly like those here
shown, not differing more than the papillae in different sea lampreys.

A-f&. From the fringe at the meson and the cephalic edge of the
disc.

C-D. Papillae from the side of the disc.

&. Papillae from the meson at the caudal side of the disc.

FIG. 21. (X 3%). Ventral aspect of the head of a brook lamprey to
show the number and arrangement of the teeth. The body opposite the
gills is enlarged, as the photograph was taken during the inspiratory
phase. The whole dentition is seen to be weak as compared with the
lake or sea lamprey. The lingual tooth plate is also markedly different.

E£. Eye.

S. O. Sensory organs or nerve papillae.

488 Simon Henry Gage

A-C. (X 12.) At the left. Papillae from the circumoral fringe of the
brook lamprey. is from the meson at the cephalic edge, # from the
side, and C from the meson at the caudal edge of the disc.

FIG. 22. (X 16). Ventral view of the head of a larval lamprey 135
millimeters long to show the ventral lip, the upper or dorsal hood-like
lip, and the branched tentacles forming a sieve over the entrance to the
mouth. In this figure the tentacles are somewhat unnaturally separated.
During life they are more closely approximated, thus making a fine
strainer to prevent the entrance of coarse particles into the branchial
cavity. By comparing with figure 41 of plate vii, the entire tentacle
will be seen to resemble a cauliflower somewhat.

D.L. Dorsal lip or hood. It embraces the lateral extensions of the
ventral lip.

L. 7. The ventral median tentacle which may be designated the
lingual tentacle as it is supposed to be an important factor in the for-
‘mation of the adult tongue.

V.L. Ventral lip. Its lateral extensions are entad of the dorsal lip.

FIG. 23. (X 16). Ventral view of the head of a transforming larva,
to show the narrowing of the head and mouth at this stage, and also
the arrangement of the tentacles around the oral disc, as if they were
to be transformed into the future teeth. The union of the dorsal and
ventral lips to form the circular, oral disc is also shown.

D.L.and V. LZ. The dorsal and ventral lips in the process of fusing.

L. T. The tongue which appears to be derived largely from the me-
dian lingual tentacle. Compare figure 22.

Fic. 24. (X 3). Annular cartilage of a lake lamprey, to show the
form of the cartilage and the position of the supra- and infra-oral teeth.

/. Foramen opening into the interior of the cartilage. ‘There is
something of an angle at the point of entrance of the foramina
and the general appearance is strikingly like the jaws of a shark.

Z. Z. Infra oral or mandibular teeth. ‘here were nine in this speci-
men, eight in the one represented in figure 19.

S. £. Supra-oral lamina or maxillary teeth.

Fic. 25. (X 2%). Annular cartilage and part of the tongue with the
lingual teeth of a sea lamprey. The tooth plates are removed from the
annular cartilage, thus bringing into view the supporting eminences of
cartilage for each tooth.

/. _Foramen near the middle of the annular cartilage.

Z, L. Infra-oral or mandibular tooth supports.

“L. T. Lateral lingual teeth. There are thirteen on the right and but
ten on the left. Ordinarily the lateral variation is not so marked.

S. Z. Supra-oral or maxillary tooth supports.

7. Part of the tongue.

V.£Z. Ventral lingual lamina. Compare the ventral lingual tooth-
plate in figures 19-20, and 21.

Fic. 26. (X 7). Annular cartilage of the brook lamprey.

f. Foramen leading to the interior of the cartilage. “Compare the
same in figures 24, 25.

Z. L.. Infra-oral lamina supported by the ventral half of the annular
cartilage.

S.Z. Supra-oral lamina or maxillary tooth-plate supported by the
dorsal half of the annular cartilage. This plate is in marked contrast
to those of the lake and sea lamprey, where the maxillary teeth are very
close together. Brook lampreys are occasionally found with one or
more intermediate teeth ou the supra-oral lamina. (Jordan, ’82, ’85.)

The Lake and Brook Lampreys of New York 489

PLATE VII. FIG. 27-4I.

A series of transections near the middle of the body to show the
changes in the gonads (ovary and spermary) at various stages of growth ;
atrophy of the intestine in the breeding season ; nest building, and the
oral tentacles and velar fold of a larva. The scale is indicated after the
number of each figure.

Structures appearing in all the transections,all abbreviations on Fig. 27.

A. Aorta.

C. V. Cardinal veins.

G. Gonad. The reproductive gland (ovary in the female, spermary
in the male.) G. On each section. The ovary and testis are single,
foliated orgaus in the lamprey, and are supported by a fold of peritone-
um, Mesogonad, frequently called mesorchium in the male, mesoarium
in the female.

I. Intestine. JZ. On all sections.

IM. L. Intermuscular ligaments between the myotomes.

kK. Kidney and ureter.

M. Y. Myel, or spinal cord.

M. A. Mesenteric artery.

M.G. Meso Gonad. The duplicature of peritoneum supporting the
ovary (mesoarium) or spermary (mesorchium).

M. P. Muscle plates cut transversely. J. P. on Fig. 27, and 36.
Each myotome is made up of a multitude of muscle-plates or lamellae,
each in a delicate connective tissue-sac. Only the empty sacs are
shown in the figures.

M. T. Myotome or myomere. These overlap like tiles, so that in
a transection of the body the cut ends of several appear. The over-
lapping myotomes are connected by the intermuscular ligaments (///.
L

M. V. Mesenteric vein. The mesenteric vein and artery are in the
typhlosole.

NV. Nucleus. On Fig. 29 A.

NC. Notochord.

T. Typhlosole, or spiral intestinal valve ; letter on Fig. 27 and 37.
The tissue of the typhlosole appears to be largely lymphoid in charac-
ter. In the figures of the larva, the typhlosole is shown clearly to be a
linear invagination of the intestine, thus forming a ridge. Commenc-
ing somewhat cephalad of the base of the left dorsal fin, the typhlosole
or spiral valve extends cephalad as a right-spiral, and caudad as a left-
spiral.

FIG. 27. (X 2%). Tramnsection of an adult male lake lamprey taken
in December, to show the size and appearance of the spermary about
six months before the spawning season. The intestine also shows the
size and general structure in the feeding specimens.

Fic. 27, A. (X53 and 700). A. Sperm mother-cell showing the multi-
tude of sperm-cells within it. 4, C. Individual sperm-cells magnified
702 diameters, to show their structure and appearance. In BZ, from an
osmic acid preparation, two black spherules are shown in the darker
part. JD, A red blood-corpuscle with its eccentric nucleus, at the same
magnification as B, C, to show the relative size of sperm-cells and red
blood-corpuscles.

Fic. 28. (X 20). Figure of the edge of a lamella or lobule of the

spermary, from the same specimen as figure 27, to show the appearance
of the sperm mother-cells by reflected light. By comparing with figure

490 Simon Henry Gage

30 one can readily see the difficulty in distinguishing spermary and
ovary. When properly prepared and viewed as transparent objects,
however, the difference between the sperm mother-cells and the ova is
most striking.

FIG. 29. (X 2%). Transection of a female lake lamprey taken in
Deceniber, 7. é., about six months before spawning. To show the size
of the ovary and of the intestine ; compare description of Fig. 27 and
28.

Fic. 29 A. (X 53). Asingle ovum from the ovary of the same speci-
men as figure 29. ‘To show the comparative size and general character
of the ovum, with its eccentric nucleus ; also to compare with a sperm
mother-cell of the same stage of development. Compare Fig. 27 A.

Fic. 30. (X 20). End of alobule of the ovary of the same speci-
men as figure 29. To show the general appearance of the ovary and ova
about six months before spawning. Also the similarity in appearance
of ovary and spermary at this stage of maturity. Compare Fig. 28
with its description.

FIG. 31. (X 2%). Transection of a male lake lamprey in the breed-
ing season, to show the relative size of spermary and intestine, and for
comparison with the spawning female (Fig. 32), and the non-spawning
male (Fig. 27), also the enormous dorsal ridge appearing in the male
lake lamprey during the breeding season.

YD. Dorsal ridge.

Fic. 32. (X 2%). Transection of a female lake lamprey in the
spawning season. Some of the ova are free. Compare with the non-
breeding female (Fig. 29), and the breeding male (Fig. 31). While in
the male the spermary is considerably larger at the breeding season, the
ovary has far more strikingly increased in size.

Fic. 32 A. (X 53). Ovum of the spawning lake lamprey. The nu-
cleus is obscured by the great amount of food-yolk. This figure is of
the same magnification, and is introduced for comparison with figures
29 A, 34 A, 36 A, and 38 A, to show the difference in size of the ovum at
various stages of maturity. It is also at the same maguification as the
sperm-mother cells shown in fignres 27 A, and 35 A.

FIG. 33. (X 6). Transection of a just transformed male lake lam-
prey taken in October, and about 150 millimeters in length. To show
the size of the spermary and of the intestine, and for comparison with
a female at this stage (Fig. 34).

Fic. 34. (Xx 6). Transection of a just transformed female lake lam-
prey, about 150 millimeters long, taken in October. To show the ovary
and intestine, and for comparison with the male at this stage (Fig. 33),
also with the female brook lamprey (Fig. 36).

Fic. 34 A. (X 53). Ovum from the same specimen as figure 34. To
show the size of the ovum at the time of transformation, and for com-
parison with the ovum of a brook lamprey at the same stage (Fig.
36 A), also with a larva (Fig. 38 A).

Fic. 35. (X 6). Transection of a just transformed male brook lam-
prey, about 190 millimeters long, caught in October. To show the in-
testine and the spermary, and for comparison with the just transformed
female brook lamprey and the lake lamprey at the same stage (Fig. 33,
34). It will be noticed that the intestine is relatively smaller than in
the just transformed lake lamprey.

Fic, 35 A. (X 53). Single sperm-mother cell of the just transformed
brook lamprey, from the same specimen as figure 35.

The Lake and Brook Lampreys of New York 491

Fic, 36. (X 6). Transection of a female brook lamprey, about 190
millimeters in length. Just transformed ; caughtin October. Forcom-
parison with the male (Fig. 35), and with the female lake lamprey at
the same stage (Fig. 34). It will be seen that the brook lamprey’s
ovary is much nearer maturity than is that of the just transformed lake
lamprey.

Fic. 36 A. (X 53). Ovum from the ovary of the same specimen as
figure 36. To show the size of the ovum in the just transformed brook
lamprey, aud for comparison with the lake lamprey Gigs 34 A) vt
will be seen that this ovum is even larger than the one from the ovary
of a lake lamprey six months before spawning (Fig. 29 A). From the
appearance of sexual maturity it is believed that the brook lamprey
spawns the spring following its transformation. -

Fic. 37. (X 6). Transection of a larval male lamprey, 140 millime-
ters long ; caught in November. To show the small spermary and the
intestine with a crescent-shaped lumen, due to the intruding typhlosole
or valve ; no secondary folds are present as in the adult.

Fic. 38. (X 6). Transection of a larval female lamprey, 150 millime-
ters long; taken in November. To show the ovary with the ova and
the intestine. It was not cut at the same level as figure 37, hence the
spiral valve or typhlosole occupies a different position.

Fic. 38 A. (X 53). Ovum from the ovary of the same specimen as
figure 38.

Fic. 39. Section of a lake lamprey’s nest with a pair of lampreys.
The nest is sectioned parallel with the stream ; it is represented in the
usual place for a lamprey’s nest, just above ripples.

The female lamprey is represented as moored to a large stone, while
the male is backing down stream carrying a stone of considerable size.
It will be readily seen that disturbance of the stones at the upper edge
of the nest would loosen the sand, and that it would be washed down
stream and thus tend to fill the bottom of the nest, asshown. Mingled
with the sand at the bottom of the nest are seen numerous ova, indi-
cated by white circles.

Fic. 40. Face view of a creek with two lamprey nests just above rip-
ples. In one nest two lampreys are indicated and in the other but one.
In the concavity of the stream, where the water flows somewhat slowly,
there is shown a deposite of sand and mud. It is in such situations that
the larvee live after leaving the nest.

Fic. 41. (x 8). A medisection or median sagittal section of a larval
lamprey, 135 millimeters long. To show the oral tentacles, one side of
the velum, and the relation of the velum to the branchial chainber.
To be compared with the frontal section shown in figure 52, Plate VIII.

B.R. Branchie. They occupy acommonchamber. The B. R. is on
the third gill.

D.L. Dorsal lip orhood. Nearly its entire substance is muscular.

N. Single nasal opening.

N.C. Notochord.

V. ZL. Ventral lip.

VELUM. The right half or fold of the velum. There is a similar
one in the left half of the body. Compare with figure 52 of Plate VIII.

PLATE VIII.

Fic. 42. (X about 1000), Red Blood-Corpuscles of lake, brook and
larval lampreys. (From the New York Medical Journal).

492 Simon Henry Gage

A. Red blood-corpuscles of the lake lamprey. a, face view of a cor-
puscle ; 6, optical section of a corpuscle on edge; c, face view of a cor-
puscle, showing the nucleus after the action of one per cent. acetic
acid ; d, cup-shaped corpuscle.

; wv Red blood-corpuscles of the brook lamprey. a, 0, c, the same as
ees B

C. an blood-corpuscles of a larval lamprey 142, mm. long. a, 0, ¢,
as in 4.

PD. Red blood-corpuscles of a larval or embryo lamprey, 9 mm. long.
a, 6, c, the same as in A.

&. Rouleaux of the corpuscles of the brook lamprey in optical sec-
tion. In the lower corpuscle a nucleus is indicated to show that it is
small and in the thickest part of the corpuscle. It is visible only after
the hemoglobin is partly or wholly renioved from the corpuscle. Inthe
embryo, where the corpuscles are so small, the nucleus is faintly visi-
ble in many corpuscles before the removal of the hemoglobin.

F. Rouleaux of the 142 mm. larva focused on the upper surface. In
both &. and /. the corpuscles are shown of different sizes. Compare
the maximum and minimum diameters in the table of measurements.

FIG. 43. (X about 1000). A single white blood-corpuscle in various
amceboid phases, drawn freehand within two minutes.

Fic. 44. (X about 1000). Fibrin filaments of a larval lamprey. The
filaments seem to radiate from centers, the centers appearing like white
blood-corpuscles. Some of the filaments are moderately coarse, others
exceedingly fine. c. a red blood-corpuscle with eccentric nucleus.

FIG. 45. (X about 1000). Human blood fibrin, to show the coarse-
ness of the filaments and also centers of radiation. c. A red corpuscle
drawn at the same scale.

Fic. 46. (X 700). Zoosperms of a lake lamprey. Three are shown
entire. On each is a bulbous termination of the tail, and in the one at
the right is an enlargement of the tail near the tip.

A. Two heads (X 2750). In the one at the right are shown two
clear highly refractive bodies.

Fic. 47. Zoosperms of the sea lamprey. A single zoosperm drawn
entire and magnified 700 diameters.
A. A head and the bulbous termination of the tail (X 2750.)

Fic. 48. Zoosperms of the brook lamprey. Two entire ones are
shown at a magnification of 700. The tail of the one at the right is
nearly uniform and ends in a point. ‘The one at the left ends by a little
knob as with the lake and sea lamprey.

A. Two heads magnified 2750 diameters.

Fic. 49. (Natural size). A glass vessel containing sand and water
with a larval lamprey in its burrow, to show the position naturally as-
sumed by the larve.

FIG. 50. (X 3). Head of a lake lamprey in the transforming stage to
show the narrowed head and the snow white pineal eye.

I, 2. The first two branchiopores. dc. Posterior dorsal cartilage.

ept. Epiphysis or pineal eye surrounded by a light area.

2. Nostril with the opening directed obliquely cephalad

Fic. 51. Oblique view of the head and branchial region of an adult
lamprey showing the direction of the expiratory currents from the
branchiae and from the nasal sac.

bp. The branchiopores.

z. Nostril pointing obliquely cephalad.

The Lake and Brook Lampreys of New York 493

so. Sensory organs, or nerve papillae. Compare plates V and VI.

FIG. 52. (X44). Frontal section, looking dorsad, of a larval lam-
prey, to show the velum and the course of the respired water.

I, 2, 3. Branchiopores covered with valves extending from the ceph-
alicedge. 6, 6, 6,6, Branchiae seen in section.

Ah. Wood or upper lip.

Z. Oraltentacle. v,v. Velum. The two independent velar folds
are Shown in section.

vl. Valve over the branchiopore. In this one it is open for the pas-
sage of the expiratory stream, which is indicated as passing between
the lamelle of two contiguous gills.

The arrows show the stream entering the mouth through the straining
tentacles, then between the two halves of the velum into the branchial
chamber where it divides, part passing out between the gills of each
side, and through the corresponding branchiopores.

FIG. 53, 54,55. (X44). Three views of the valves at the opening of
the branchiopores that serve to direct the streams of water in inspiration
and in expiration in the adult.

6, 6. Branchize seen in section.

cl. Clavus or peg. Asmall, stiff, pointed body about 2 mm. high,
arising on the caudal margin, and opposite the middle of the branchi-
opore. In expiration the two valves meet at this point, as shown in fig-
ure 55.

ye Binge of papilla on the caudal margin of the branchiopore.
Their relation to the clavus is well shown in fig. 55.

vl. Valves. There are two, one extending dorso-ventrad as
shown entire in fig. 55, and in section in fig. 53, 54. This one corre-
sponds with the single valve of the larva.

The second, is a double valve within the branchiopore. In inspiration
the two parts move up against the cephalic side of the branchiopore and
are covered with the ectal or transverse valve and thus serve to guide
the water directly into the gill sac. In expiration, fig. 54, 55, they rest
against the caudal wall of the branchiopore, and, with the ectal trans-
verse valve, make a tube directed obliquely caudad, thus giving a cor-
responding direction to the expiratory streams of water. See also fig.

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