Miriam F. Bennett

Changes in the blood of newts,Notophthalmus viridescens, following the administration of hydrocortisone

SummaryAdult newts,Notophthalmus viridescens, were injected with suspensions of hydrocortisone acetate (experimentais) or with distilled water (controls). Forty-eight and 72 hours after treatment, blood smears were prepared, and differential counts of leucocytes were made for the experimental and control animals. At 48 hours, the distributions of neutrophils, eosinophils, basophils, monocytes and lymphocytes were much the same in the two groups of newts (Table 1). However, by 72 hours after injection, increases in neutrophils and decreases in lymphocytes were obvious in the animals which had received hydrocortisone. Such changes were not seen in the controls (Table 2). The changes in the distribution of the white cells seen 72 hours after treatment are very similar to those known to occur in mammals treated with adrenal steroids and to those described earlier in two species of frogs injected with hydrocortisone. Details of some differences in the responses of the amphibians are discussed.

Osmotic Stress, ACTH and the White Blood Cell Picture in Newts, Notophthalmus viridescens*

SummaryAdult newts,Notophthalmus viridescens, were given single injections of 0.04 I.U. of bovine ACTH or were immersed in 2% NaCl for 2 hours. In both the corticotrophin-treated and the osmotically-stressed newts, increases in neutrophils and decreases in lymphocytes were obvious and significant. Neither condition was observed in the controls (Tables 1 and 2). The changes seen in the peripheral blood of the experimentalNotophthalmns were very much like those reported earlier for animals of the same species which had received injections of the adrenal steroid, hydrocortisone. Using these lines of evidence, it is argued that neutrophilia and lymphopenia in amphibians could result from a stress → anterior pituitary → steroidogenic tissue-system of reactions which has been proved to effect similar changes in the blood of stressed mammals.

The diurnal cycle and a difference in reaction times in earthworms

Summary1.The time necessary for the withdrawal of the anterior end of the body from an oval spot of light was found for dark-adapted earthworms, Lumbricus terrestris L., during test periods which started at 12:00 or 19:00 hours.2.For 309 trials begun at 19:00, the average reaction time was 7.13 seconds and for the 308 begun at 12:00, it was 9.93 seconds.3.Here is another example of the effect of a diurnal cycle on a response typical of this species, and it is discussed in regard to other indicators of biological rhythmicity in earthworms.ZusammenfassungWird das Vorderende von Lumbricus terrestris belichtet, so zieht es der Regenwurm nach einer gewissen Zeit (Reaktionszeit) zurück. Diese Reaktionszeit wurde für dunkeladaptierte Regenwürmer um 12.00 Uhr und um 19.00 Uhr gemessen. Mittags beträgt die Reaktionszeit im Mittel 9,93 sec (308 Versuche), abends 7,13 sec (309 Versuche; p< 0,001). Die Reaktionszeit unterliegt also tagesperiodischen Schwankungen, die im Zusammenhang mit anderen vom Regenwurm bekannten Erscheinungen biologischer Rhythmik diskutiert werden.

The diurnal cycle and locomotion in earthworms

Summary1.The time necessary for crawling 10 cm up an incline of 45° was found for earthworms, Lumbricus terrestris L., during test periods starting at 700, 1200 and 1900.2.For 446 trials run in the morning, the average time was 17.19 seconds. For 475 tests done at midday, the average was 21.52 seconds, and for 475 trials run at 1900, it was 16.49 seconds. The differences between the averages for 700 and 1200 and for 1200 and 1900 are significant (p<0.001).3.These results and differences in light-reaction times at 1200 and 1900 are compared.Zusammenfassung1.Die Zeit, die Regenwürmer (Lumbricus terrestris L.) benötigen, um auf einer schiefen (45°) Ebene 10 cm aufwärts zu kriechen, wird um 700, 1200 und 1900 Uhr gemessen.2.Um 700 Uhr beträgt diese Zeit im Mittel 17,19 sec (446 Versuche), um 1200 Uhr 21,52 sec (475 Versuche) und um 1900 Uhr 16,49 sec (475 Versuche). Der Unterschied zwischen 700 und 1200 und der zwischen 1200 und 1900 ist statistisch gesichert (p<0,001).3.Diese Ergebnisse werden mit der Lichtreaktionszeit von Lumbricus verglichen.

Geomagnetic effects on a circadian difference in reaction times in earthworms

ZusammenfassungDie Wirkung des erdmagnetisohen Feldes auf die Lichtreaktion von Lumbricus terrestris wurde untersucht (Herbst 1968). Als Test wurde die Reaktion auf einen Lichtreiz verwendet. Ein Teil der Würmer wurde im natürlichen erdmagnetisehen Feld, ein anderer Teil in einem auf Null kompensierten Feld gehalten. Die Reaktionszeiten auf den Lichtreiz wurden bei beiden Gruppen um 12.00 und um 20.00 Uhr gemessen. Die Reaktionszeiten im natürlichen erdmagnetischen Feld waren abends signifikant (p=0,005) kürzer (7,2 sec) als mittags (8,9 sec). Im Feld, das nahezu auf Null kompensiert war, waren die Reaktionszeiten abends und mittags gleich (8,8 bzw. 8,7 sec). Der Erdmagnetismus hat also einen Einfluß auf die circadiane Differenz der Reaktionszeiten bei Lumbricus.SummaryThe effect of geomagnetic force on the light-withdrawal reflex of earthworms, Lumbricus terrestris, L., was investigated during the autumn of 1968. The reactions of worms kept in the earths magnetic field were timed beginning at 12:00 and at 20:00, E.S.T. on each of 63 days; the same was done for worms maintained in a field whose intensity was essentially zero. The worms in the earths field withdrew from light significantly faster at night then at midday. No significant difference between the mean reaction times at 12:00 and those of the evening were found for the animals which lived and were tested in the greatly reduced magnetic field. Therefore, geomagnetism does have some effect on the circadian difference in reaction rates in this species.

The brain and rhythmicity in earthworms

Summary1.Light-withdrawal reactions and locomotion were timed in earthworms, Lumbricus terrestris,L., from which the supraesophageal ganglia had been removed. These tests were made during periods starting at 12.00 and 19.00, E.S.T.2.For 367 tests which commenced at noon, locomotion through 10 cm averaged 21.1 seconds and for 359 tests made in the evening, the average was 20.3 seconds. Withdrawal time at 12.00 (443 tests) averaged 24.1 seconds, and for 443 tests of the evening, the average was 24.2 seconds.3.Comparison of these results with those published earlier proves a major role of the brain in the mediation of indicators of rhythmicity in these worms.Zusammenfassung1.Die Lichtreaktionszeit von Lumbricus ohne Gehirn und die Zeit, die diese Würmer benötigen, um 10 cm zu kriechen, wird um 12.00 und 19.00 Uhr gemessen.2.Um 12.00 Uhr beträgt die Lichtreaktionszeit im Mittel 24,1 sec (443 Versuche) und um 19.00 Uhr 24,2 sec (443 Versuche). Um 10 cm zu kriechen, benötigen die operierten Tiere um 12.00 Uhr im Mittel 21,1 sec (367 Versuche) und um 19.00 Uhr 20,3 sec (359 Versuche). Normale Regenwürmer sind schneller um 12.00 als 19.00 Uhr (Bennett und Reinschmidt, 1965a and 1965b).3.Diese Ergebnisse beweisen die Wichtigkeit des Gehirns für biologische Rhythmen bei Lumbricus.

The phasing of the cycle of motor activity in the fiddler crab, Uca pugnax

Summary and Conclusions1.The spontaneous locomotor activity of groups of fiddler crabs which were collected from two different beaches where comparable tidal events differ by four hours was recorded under constant laboratory conditions during two different periods in the summer of 1959.2.During the first 24 hours in the laboratory, the phases of the cycles of activity of tidal or lunar-day frequency were correlated with tidal phases which obtain in the original habitats of the crabs.3.Gradually the interval of time between peaks of activity for the two groups of animals shortened, and by the seventh or eighth day of observation, the peaks were essentially synchronous, and correlated with the times of zenith and nadir of the moon. These relationships continued through the remainder of the periods of observation.4.These results show that although the phases of such cycles can be set in adaptive relationships with actual tidal events in the organisms natural environment, the cycles are correlated primarily with lunar events.5.It is suggested that further study and comparison of the indicators of lunar rhythmicity, color change and locomotor activity, in this species, may be especially helpful in the working out of the mechanisms by which phases of such cycles are set and regulated.ZusammenfassungWährend zweier Perioden im Sommer 1959 wurde die Laufaktivität von Winkerkrabben (Uca pugnax), die von Chappaquoit Beach (Massachusetts) und von Lagoon Pond, Marthas Vineyard (Massachusetts) gesammelt wurden, im Laboratorium (Marine Biological Laboratory, Woods Hole) unter konstanten Licht- und Temperaturbedingungen registriert. Chappaquoit, Lagoon Pond und Woods Hole liegen innerhalb eines Radius von etwa sechs Meilen; die Zeiten von Ebbe und Flut sind jedoch an diesen Stellen sehr unterschiedlich: Zwischen Chappaquoit und Lagoon Pond beträgt der Unterschied 4 Std, zwischen Chappaquoit und Woods Hole nur 1,5 Std.In ihrer natürlichen Umgebung am Strand läuft und frißt Uca vor der Zeit des Niedrigwassers. Am 1. Tag der Untersuchung im Laboratorium unter konstanten Bedingungen entsprachen die Phasen der Laufaktivität der beiden Gruppen den Phasen der Gezeiten an dem entsprechenden Biotop: Die Phasen der Tiere von Lagoon Pond lagen also später als die der Tiere von Chappaquoit.Allmählich wurde der Unterschied zwischen den Phasenlagen der beiden Gruppen kürzer; am 7. oder 8. Tag stimmten sie überein und fielen mit den Phasen des Mondumlaufes (Zenit oder Nadir) zusammen.Demnach werden in Anpassung an die Umwelt unter natürlichen Bedingungen (unter dem Einfluß von Ebbe und Flut) die Aktivitätsphasen durch von den Gezeiten stammende Faktoren reguliert; primär wird der Aktivitätszyklus jedoch von den Faktoren des Mondumlaufes bestimmt.Der Unterschied zwischen dem Rhythmus des Farbwechsels von Uca und dem Aktivitätsrhythmus wird diskutiert.

Persistent seasonal variations in the diurnal cycle of earthworms

SummaryAn annual cycle, based on the differences between the speed of locomotion around midday and in the evening, was found for earthworms,Lumbricus terrestris L., maintained in the laboratory under constant conditions of light and temperature, and studied during parts of 1965, 1966, 1967 and 1968. During each month, the worms were faster in the evening than at noon, but this difference varied in degree through the year (Fig. 1). In addition, during part of the year, the differences between midday and evening were much greater for a 15-day period which centered on full moon than for a block of 15 days centered on new moon. Therefore, seasonal changes in lunar correlations were also indicated. These rhythms have been compared with others of lunar and annual frequencies, and their possible biological significance has been discussed.ZusammenfassungIn den Jahren 1965 bis 1968 wurde das lokomotorische Verhalten von Regenwürmern (Lumbricus terrestris L.), die bei konstanter Beleuchtung und Temperatur unter Laboratoriumsbedingungen gehalten wurden, untersucht; und zwar wurde mittags (12.00 Uhr) und abends (19.00 Uhr) die Zeit gemessen, die die Tiere benötigen, um 10 cm zu kriechen. Die Auswertung der Versuche zeigte, daß die Würmer abends immer schneller waren als mittags. Die Differenz der beiden Kriechgeschwindigkeiten schwankte jahresperiodisch (Fig. 1). Außerdem ergaben sich Hinweise dafür, daß die Mondphase von Bedeutung ist: Im Frühjahr und im Winter war der Unterschied zwischen der mittäglichen und der abendlichen Kriechgeschwindigkeit in der Woche vor und nach Vollmond viel größer als in den beiden Wochen um Neumond. Die Rhythmen der Lokomotionsgeschwindigkeit werden mit anderen Jahres- und lunarperiodischen Erscheinungen verglichen; ihre mögliche biologische Bedeutung wird diskutiert.

Isolation of the brain and rhythmicity in earthworms

Zusammenfassung1.Bei Lumbricus terrestris L. wurden die Nerven zwischen den Gehirnganglien und den Unterschlundganglien durchschnitten. Die Lichtreaktionszeit und die Kriechzeit von diesen Würmern wurden um 12.00 und 19.00 Uhr gemessen.2.Um 12.00 Uhr beträgt die Liohtreaktionszeit im Mittel 9,9 sec, um 19.00 Uhr 10,3 sec. Um 12.00 Uhr beträgt die Kriechzeit im Mittel 10,6 sec und um 19.00 Uhr 11,1 sec.3.Normale Regenwürmer sind schneller um 19.00 Uhr als 12.00 Uhr (Bennett und Reinschmidt, 1965a und 1965b). Aber Lumbricus ohne Gehirn (Bennett und Willis, 1966) wie solche mit durchtrennten Connectiven verlieren diese zwei biologischen Rhythmen.Summary1.In earthworms, Lumbricus terrestris L., the connectives between the supraesophageal and the subesophageal ganglia were severed. For these worms, locomotion and light-withdrawal were timed during periods starting at 12:00 and 19:00, E.S.T.2.The average time taken to crawl 10 cm at 12:00 was 10.6 seconds and at 19:00, it was 11.1 seconds. The average withdrawal time at midday was 9.9 seconds and at 19:00, it was 10.3 seconds.3.Therefore, the variations between midday and evening performances of normal worms (Bennett and Reinschmidt, 1965a and 1965b) were abolished by cutting the connectives as they were by the removal of the brain (Bennett and Willis, 1966).

Bilateral symmetry in the mediation of circadian differences in earthworms

SummaryThe rates of locomotion and light-withdrawal of earthworms, Lumbricus terrestris L., in which one circumpharyngeal connective had been severed were compared with those of normal worms during test-periods which started at 12:00 and 20:00, E.S.T. Normal worms withdrew from light and crawled faster during the evening hours than at midday. The animals in which the connective had been cut performed at essentially the same rates during the noon and evening periods. Data presented in the table show the similarity between the results of this investigation and those of earlier studies on brainless worms and on Lumbricus in which both circumpharyngeal connectives were cut (Bennett, 1967). The new findings support the earlier conclusion that an intact anterior central nervous system is necessary for the mediation of circadian differences in earthworms, and indicate that the regulating mechanism of the temporal differences is one which demands the participation of neural units of both sides of the anterior central nervous system.