PHYSIOLOGY, CHEMISTRY AND PATHOLOGY 27 



dent that, excluding such an unforeseen factor, these animals on the whole 

 made the more ideal subjects for pineal experimentation. Litters are 

 large and the interval between birth and sexual maturity is longer than 

 in guinea pigs. The pineal gland itself is much shorter and less fragile, 

 and can be picked out easily and surely with a pair of small forceps. 

 Aside from the demonstration of the comparative ease of the operation, 

 which indicates that this species is the most desirable for future studies, 

 the results for immediate purposes were inconclusive. 



Dandy's Experiments. Dandy, in 1915, described a new and simple 

 operative technic which obviates much of the trauma, and consequently 

 lessens the mortality. 



The new operation can be done in less than one hour. It differs from 

 earlier operations, in that the pineal is reached from in front through the 

 third ventricle, rather than from behind. In this way the extensive bleed- 

 ing consequent to liberation of the vein of Galen is obviated, side-tracked 

 as it were, and the operation can be performed almost bloodlessly. 



The method is to divide the splenium of the corpus callosum in the midline for 

 a distance of about 2 cm. from its posterior terminus. This exposes the transparent 

 roof of the third ventricle, which is distended by the contained cerebrospinal fluid. A 

 large anemic area is visible in the midline of the roof of the ventricle, between the two 

 small veins of Galen. This is perforated and the opening enlarged backward to the 

 origin of the vena Galena magna by releasing the blades of the forceps. The entire 

 third ventricle is thus brought in full view and under the origin of this vein, in 

 the median quadrigeminal groove, the pineal body is readily seen. It can easily be 

 grasped in the jaws of the cupped biting forceps and completely removed. The accom- 

 panying drawings by Broedel render any description of this operative procedure su- 

 perfluous. (See original publication.) 



Practically no bleeding occurs during the exposure of the gland. A little bleeding 

 follows its removal, but this can easily be controlled by a minute tampon of cotton. 

 With collapsed ventricles the bleeding is outward through the wound and is, therefore, 

 not to be feared. Not infrequently, the aqueduct of Sylvius may be filled with blood. 

 This has never caused any mortality because, before closure, the mold of clotted 

 blood may be readily extracted, the aqueduct of Sylvius being in full view. To insure 

 complete excision a second piece of tissue was invariably removed from the pineal re- 

 gion. With this method of operating there has been practically no mortality. It is 

 however, quite easy to become disoriented, even when following carefully Dandy's 

 procedures. If bleeding and laceration of tissue are avoided, as they can be, and the 

 midline is adhered to, there is little danger of losing one's bearings. 



Dandy made use of this method in removing the pineal gland from a 

 series of dogs, mainly young puppies, from ten days to three weeks old. 

 Of these one lived fifteen months after the operation; one died of dis- 

 temper one year after operation; several survived the loss of the pineal 

 three to eight months. Dandy was, however, unable to note any difference 

 in the resistance of the operated and the control animals to the usual 

 diseases. 



When litters of puppies could be obtained, one or more of the animals 

 were kept as controls. Little importance, however, should be attached to 

 such comparisons because of the great variations found in members of 

 the same family. The pineal was also removed in several adult male 

 and female dogs, and three of these lived longer than four months after 

 the operation. 



