The pineal fed and control animals of both sexes are of nearly the same bodyweight regardless of careful treatment, although only a slight decrease in body weight can be seen in the case of the experimental group. On comparing the results of this pineal feeding experiment, the writer's results coincide with those of HOPKINS, entirely different from those of MC. CORD and of DANA-BERKLEY. The growth records of pineal fed animals, reported by DANA-BERKLEY as well as by MC. CORD are not important because they failed to say in the account of their experiments whether the animals were selected from the same litters. Sexual precocity was noted by MC. CORD, but this easily explained by the fact that the somatic growth normally is accompanied by a corresponding development of the reproductive organs.
In this investigations ovaries and testes of the pineal fed animals appear very slight under weight as compared with the controls.
Very serious error might easily creep into the conclusion from an investigation which includes animals from several different litters. To draw conclusions from such investigations is always dangerous. In the writer's experiment the pineal substance was given in amounts considerably larger than those fed to guinea-pigs by MC. DORD and others. During the ten weeks observation there seemed no evidence to indicate that toxic effects or gastrointestinal disturbances were produced by high doses medication. As pointed out above, in the present investigation care was taken to select the animals from the same litter and the experimental and control animals were kept and fed under the same conditions.
Pineal feeding produces no constant or apparent effect upon the growthrate of the body or organs of guinea-pigs, beyond differences probably within the normal limits of variation, although only slight retardation in the growth of testes and ovaries is noted in favour of the pineal fed animals.
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