DEPARTMENT OF EMBRYOLOGY. 119 



during growth, but that obliteration is not the invariable rule is shown 

 by Dr. A. H. Schultz, who reports its presence in a very old human 

 skull. The widest and most typical canal was found in the skull of a 

 white man 40 years of age and a narrower one in the skull of a white 

 woman 75 years of age. It was noted also in a Filipino 30 years old, 

 but in this case was partially obliterated. In one instance the con- 

 dition was associated with a persistent sutura occipitalis transversa, 

 forming an os Incse verum. The posterior end of the canaHs basilaris 

 was found in 5 fetal and infant skulls, and in one of these was combined 

 with the likewise rare persistence of a canalis cranio-pharyngeus. These 

 two abnormal canals have several features in common : both are rem- 

 nants of embryonic structures which normally disappear during the 

 first half of intrauterine life; both are noted more frequently in children 

 than in adults, and when present are usually partially obliterated. It 

 is highly improbable that the canaHs basilaris can be regarded as an 

 atavism; it is much more likely to be due to an early or rapid ossifica- 

 tion coincident with the tardy disappearance of the chorda dorsalis. 

 More data are necessary, however, before definite conclusions as to its 

 phylogenetic role can be reached. 



Mention may be made here of the experiments of Dr. Schultz to 

 determine the effect of formalin solutions upon the size and weight of 

 fetuses during prolonged periods of preservation. He followed these 

 changes in a series of human fetuses and also, for purposes of compari- 

 son, in a series of pig fetuses. The latter were used to detect any 

 possible influence which the condition of the specimen at the time it is 

 preserved might have upon later changes in formalin. Some of the 

 pigs were preserved in an absolutely fresh state; others (from the same 

 litter) were exposed to the air for 15 hours, and still others were kept 

 in water for 3 days before being preserved. The condition of the 

 specimens in the latter two series simulated respectively the state of a 

 fetus that dies some time before it is aborted and that of a fetus that 

 is not placed in formalin immediately after it is aborted. In neither 

 of these series was there any apparent effect upon the later changes in 

 size, a fact which tends to confirm the conclusion, already drawn from 

 a study of human material, that a fetus in good condition will undergo 

 as much change in formalin as will one in poor condition. The weight, 

 however, increases if the specimen is preserved fresh, as contrasted to 

 a decrease in one preserved in poor condition. After 9 months of 

 preservation the sitting height of the human fetus was found to have 

 decreased on an average of 2.5 per cent, while the length and breadth 

 of the head increased 0.9 and 4.8 per cent respectively. The indi- 

 vidual variations were quite marked. The greatest and most rapid 

 changes occurred in the first few weeks of preservation. The absolute 

 size appears to have no influence upon the relative amount of change in 

 the measurements studied. 



