TERATOLOGY. 



953 



formation, it is certain that it may be said 

 to be an arrest at an earlier period of evolu- 

 tion ; but this is not certain with regard to 

 the vesica fissa. The origin of this can only 

 be explained by an imperfect developement of 

 the urinary bladder from the allantois. It is 

 not improbable, as my drawing of the cloacal 

 formation shows also, that the urinary bladder 

 is formed by two half-parts, which approach 

 each other anteriorly and posteriorly on the 

 mesial line. If this junction does not occur, 

 the different forms of vesica inversa will be 

 formed. Atresia ani is, in the cloacal dis- 

 position, without doubt, an arrest of deve- 

 lopement at an early period of embryoge- 

 nesis ; for previously the anus is closed. And 

 epispadias shows that the penis is formed 

 by two parts, which may remain separated 

 from each other on the superior surface. Con- 

 sequently it appears, that the name of vesica 

 inversa is as improper as that of vesica fissa. 

 But I shall propose no other name, because 

 we know sufficiently the meaning of it. 



5. Cervical Fissure (Fistula colli congenita), 



Recent observations teach us that the ori- 

 ginal branchial fissures may persist in the 

 neck even in adults. Hyrtl mentioned this 

 malformation in a man of twenty, in whom the 

 external cervical opening was small and com- 

 municated with the pharynx close to the epi- 

 glottis. Among 34,000 young men, Riecke 

 found a fistula colli congcnita twice. 



6. Fissure of the Face. 



In order to obtain a correct notion of 

 the different forms under which fissure of 

 the face may occur, it will be necessary to 

 know the gradual metamorphoses of the face 

 during its developement. Originally there 

 is a common oral and nasal cavity. The place 

 of the nose is occupied by two fissures, which 

 extend from the internal angles of the eyes 

 to the superior margin of the oral cavity. 

 There is at this period not the least indication 

 of a palate, so that the mouth and the nose 

 form one common cavity. In a human fetus 

 of less than an inch in length, Meckel found 

 the first rudiment of a palate, in the form 

 of an arc or a horse-shoe shape. On each 

 side this arc is gradually completed, so as to 

 be at first open at its posterior part, but closed 

 afterwards, and forming a complete trans- 

 verse plate, separating the nasal from the oral 

 cavity. Rathke examined this more in de- 

 tail, in fetuses of the sheep : 



1. He learned that the supermaxillary ca- 

 vity is formed on each side from the lateral 

 walls of the cranium. 



2. That between those two parts grows 

 out of the frontal wall of the skull a third 

 eminence, which forms the basis for the sep- 

 tum of the nose, that is, for the formation of 

 the vomer, of the septum of the ethmoid bone, 

 and of the intermaxillary bones. 



3. That the two parts, quoted under No. ]., 

 are bent inwards, and coalesce with the mesial 

 part. 



4. That the nasal cavity is at first a groove, 



and has originally a form which persists 

 through their whole life in fishes. 



5. That the oral and the na.sal cavity form 

 originally a common cavity. 



6. That the palate is originally a fissure. 

 By arrest of developement in these different 

 stages of embryogenesis, are formed the dif- 

 ferent species of facial fissure. 



a. Complete fissure of the face. The high- 

 est degree of malformation is, when the fissure 

 is extended from the angle of the mouth to 

 the internal angle of the eye, the orbits, the 

 nose, and the mouth forming but one cavity. 

 J. S. Meckel, Van Doeveren, and myself have 

 published examples of this malformation com- 

 plicated with acrania. The fissure sometimes 

 extends only over one lateral part of the face 

 (Leuckart), and in the greatest transition to 

 the natural condition it is but a shallow groove, 

 as is represented in fig. 596. 



A fissure sometimes extends in a transverse 

 direction over the head. C. Meyer observed 

 this twice in new-born sheep. In both the 

 palate had a double fissure, and the normal 

 opening of the month reached as far as the ear, 

 which in one of these lambs presented a trans- 

 verse fissure. 



b. Double labium leporinum. A transition 

 to the normal condition, yet a very imper- 

 fect one, is when the fissure is not extended 

 over the whole surface of the face, but is re- 

 stricted to the upper jaw. The highest de- 

 gree of deformity is double hare-lip with fissured 

 palate (Labium leporinum duplex cum palato 

 fisso). On each side of the upper lip a fis- 

 sure extends from the angles of the mouth 

 to the alte nasi. Between these is a protube- 

 rant tubercle, covered by a separate part of the 

 upper lip, and consequently by the external skin 

 and the gums. The tubercle is connected 

 with the septum of the nose, generally 

 obliquely distorted, and is filled up with the 

 germs of the incisors. By the confusion ot 

 the oral and nasal cavities, the true nasal ori- 

 fices are wanting, the osseous palate is defec- 

 tive, the soft palate and the uvula are fissured, 

 and the vomer united anteriorly with the pro- 

 tuberance, hangs in the midst of the fissure. 

 In a lesser degree of malformation, the alveolar 

 margin of the upper jaw is alone fissured, and 

 in the least degree the palate is complete. 



c. Single hare-lip. This name is adopted 

 for the malformation when it is limited to one 

 lateral part of the face. It may be complicated 

 with fissured palate. The lip is then, on one 

 side, fissured to the nostril, so as to form there 

 an immediate communication between the 

 oral and nasal cavity. The direction of the 

 fissure is seldom accurately in the mesial line. 

 If this occurs, it is the result of defective in- 

 termaxillary bones. The palate offers either a 

 simple or a double fissure. In a less degree 

 of malformation only the alveolar ridge is cleft, 

 and, in the least, the palate is complete. In 

 such a case the fissure of the upper lip is 

 merely a small incision. 



d. Fissure of the palate without a hare-lip. 

 The alveolar margin is in this case quite 

 complete, but the palatine and the supermaxil- 



