Frank A. Brown

MAGNETIC RESPONSE OF AN ORGANISM AND ITS SOLAR RELATIONSHIPS

1. The direction, and mean amount, of turning in snails initially directed southward into a constant symmetrical, illuminated field displays a lunar-day rhythm with minimum turning about the time of moon-rise, and maximum turning at lunar nadir. There is also a lunar-day cycle of standard deviation of snail pathways, with a minimum about moon-rise and a maximum near moon-set.2. The response of snails to an experimentally augmented magnetic field also exhibits a lunar-day rhythm with maximum turning to the left at lunar nadir.3. The specific character of the lunar-day rhythm of the response to the experimental magnetic fields gives further support for the view that magnetic field is normally involved in snail orientation.4. The mean daily response of snails to experimental magnetic fields, expressed as differences from the response of controls in the earths natural field, displays a semi-monthly rhythm. Maximum right-turning in response to a magnetic increase of 10-fold over that of the earth occurs one t...

Separation of two mutually antagonistic chromatophorotropins from the tritocerebral commissure of Crago.

Summary The tritocerebral commissure of the shrimp, Crago, has been chemically fractionated to separate 2 mutually antagonistic chromatophorotropins influencing body-coloration, a general darkening one (CDH) and a body-lightening one (CBLH).

Sinus Gland Extirpation in the Crayfish Without Eyestalk Removal

In view of the increasing volume of literature pertaining to endocrine activities of the crustacean sinus gland, it is unfortunate that the only simple and sure method of removal of these glands from the body has involved the removal of the total eyestalk. The eyestalk constituting the most important light receptor of the organism, contains, in addition to the sinus gland, several important nerve ganglia, the x-organ, and other possible endocrine sources. For this reason the usual removal of so much additional tissue with the glands leaves the interpretation of the results of eyestalk removal somewhat uncertain, to say the least. Furthermore, such a function as control of retinal pigment migration, which is believed by a number of endo-crinologists to be normally under the control of the sinus gland, has not yet been confirmed by such a crucial experiment as gland extirpation since this latter has also always involved removal of the effector mechanism as well. Nearly every recent investigator in crustacean endocrinology has at one time or another attempted to remove the sinus gland while leaving the rest of the stalk intact. The only published attempt to date 1 dealt with the highly transparent shrimp, Palaemonetes. The technic developed in this case was not sufficiently satisfactory to be used as a routine laboratory method, and furthermore could not be used successfully upon the great majority of crustaceans whose exoskeletons were relatively opaque. The simple technic described below has been devised to extirpate the sinus glands from crayfishes without eyestalk removal, and, in fact, with little apparent disturbance to the remaining functions of the stalk including vision. The operation can be performed rapidly, and after a little practice, bilateral extirpation of the glands in an animal can be accomplished in less than 5 minutes.

Phase Shifting an Exogenous Variation in Hamster Activity by Uniform Daily Rotation

It has been recently pointed out 1 that the explanation of the long intractable biological clock phenomenon probably lies with-in the domain of interaction between organisms and rhythmic subtle geophysical fields. It was proposed that the rhythmic environmental field provides the well-known essentially temperature and chemical-factor independence of the temporal foundation for the rhythmically recurring, adaptive, genetic and environmentally modified, biological patterns. The patterns, in addition, include a useful feature of phase lability between the organismic and geophysical cycles. The foregoing hypothesis suggested that associations were effected within the living system between influences of subtle geophysical fluctuations such as the electromagnetic, on the one hand, and fluctuations in such overt ones as light, temperature, sound, and chemical factors, on the other 2 . The subtle field variations were postulated not to elicit adaptive responses except as they might perhaps serve as token or predictive “stimuli” for biologically significant environmental events. Overt-factor variations, of course, include numerous ones having direct survival value for organisms. Many recent studies have disclosed that living systems are extraordinarily responsive to electromagnetic fields of closely the strength of the natural ambient ones 3 , 4 , 5 , 6 indeed organisms may display decreasing specific responsivenesses to fields both weaker and stronger. With the natural fluctuations within these fields activity rates of some organisms have been shown to be able to correlate either positively or negatively, indicating that these organisms have the ability to alter sign of response. Study of bean water uptake has indicated that this sign, whether + or —, may be determined or biased by other very weak ambient electromagnetic parameters, even ones of biological origin 7 .