356 Jacob Parsons Schaeffer. 
due to pressure caused by neighboring structures. I hope to 
study the subject more extensively in the embryo and child to 
see whether the opening, after all, at times, does not have an 
embryological significance. Thus far I must agree with Giraldes 
that the ostium maxillare accessorium does not appear in the 
embryo and young child. 
The accessory ostium varies much in size. In the series I 
studied the range of measurements was from 1 to 10 mm. long, 
and from one-half to 10 mm. wide. The opening may be round 
or elliptical. 
The appended table selected from a series of 80 specimens 
gives the range in size: 
TABLE E. 
LONG WIDE 
mm. mim. 
1 i 
2 it 
4 4 
6 4 
7 5 
10 10 
THE FRONTO-MAXILLARY RELATIONS. 
It is interesting to note that Nathaniel Highmore (1651) 
recognized the fact that the sinus maxillaris at times receives 
fluid from other sources. In his description of the cavity (see 
previous paragraph) he makes brief mention of this important 
condition. 
Antrum hoc frequentius vacuum, aliquando muco repletum reperitur, 
in quod humores a capite per meatum quendam a cavitate illa in osse 
frontis, et ab osse ethmoeide distillare poterunt. 
Although mentioning that fluid from the cavities in the frontal 
and ethmoid bones occasionally reaches the sinus maxillaris by 
way of the ‘‘meatum,’’ he does not attempt to explain how this 
is brought about. 
Tillaux (40) found when injecting fluid into the sinus fron- 
talis that some of it passed into the sinus maxillaris, instead of 
