TERATOLOGY. 



963 



Fig. 620. 



Tfie superior cervical part of a perocephalous lamb, 

 terminated by the ears which are coalesced with 

 each other. 



Fig. 621. 



The skeleton of the parts represented in fig. 620., 

 with the trachea and the oesophagus. 



a, squamous part, and b, condyloid part of the 

 occipital bone ; c, petrous ; d, squamous, part of 

 the temporal bone ; e, parietal bone ; /, auditory 

 bones. 



evolution, the head, the superior and the infe- 

 rior limbs, were wanting. There existed only a 

 trunk, which contained a tolerably large heart, 

 imperfect lungs, a ma'formed liver, a stomach, 

 and an intestinal canal. 



From this survey of the characteristics 

 which distinguish the acephali, we learn that 

 they are born with two, three, or four other foe- 

 tuses at one birth. Can this quantitative 

 multiplication of the children be the cause of the 

 qualitative malformation of one of them ? 

 This is probable by the great fertility of the 

 mothers of acephali, which also indicates 



that these monsters are produced by an 

 arrest of developement. It is very easy to 

 reduce their external appearance to the early 

 periods of developement, in which the head is 

 not yet distinct from the trunk, and iu which 

 the limbs are not yet protruded. It is worth 

 mentioning that the abdominal cavity, with 

 the kidneys and a part of the intestinal canal, 

 are the most constant organs, which is very 

 interesting with reference to the genesis of 

 the intestinal tract. In the monstrous births 

 of the second, third, and fourth type, there is 

 only a colon, while in those in which a tho- 

 rax is superadded (as in the fifth and sixth 

 types), there is also an intestinum tenue with 

 the caecum. I regard this as a confirmation 

 of the statement, that the formation of the 

 intestinal canal commences at the two ex- 

 tremes, and proceeds from these to the mid- 

 dle part. 



In the same manner the uniformity of cir- 

 cumference of the whole intestinal tube is an 

 arrest of developement at an early period of 

 embryogenesis, to which may also be referred 

 the ctecal beginning, and in many cases even 

 the ca?cal termination of the intestine. The fre- 

 quent deficiency of the liver is the consequence 

 of the absence of the stomach and duode- 

 num, and therefore a sign that the liver is a 

 protrusion of the mucous membrane of the in- 

 testinal tube. The connexion between the con- 

 taining and the contained parts is also very dis- 

 tinctly proved by the acephali. The very gene- 

 ral presence of the lumbar part of the spine 

 determines the existence of kidneys ; that of 

 the pelvis, the existence of the urinary-bladder 

 and of the genital organs. The very imper- 

 fect condition of the thorax is in relation 

 with the absence of the heart. The pre- 

 sence of vessels without a heart demonstrates 

 that the circulation of the blood can be car- 

 ried on by these alone, and that the forma- 

 tion of vessels is quite independent of that of 

 the heart. The profusion of cellular tissue, 

 by which the swollen appearance of the 

 acephali is produced, may be formative sub- 

 stance, which has not been employed in the 

 production of the other parts of the body, and 

 which has therefore grown rather abundant. 

 In this manner many of the peculiarities of the 

 acephali can be reduced to fixed principles. 



VI. Want and defective Formation of the 

 Trunk* 



The highest degree of this kind of mon- 

 strosity is where neither trunk nor limbs are 

 formed. Lycosthenes, Rudolphi, and Nichol- 

 son describe monstrous births, in which the 

 head is the only part formed. 



a. Sometimes only a part of the head is 

 ormed, of which I saw an example in a mon- 

 strous foetus born with a well-formed calf. 

 The tongue was the only well- developed part 

 in it. This shows that in the absence of all 

 the central organs, heart, lungs, skeleton, and 

 brain, there may be a well-constituted skin 



* The word trunk is here used to include the ex- 

 tremities. 



f From o, privativum, and KOD/J.OS truncus. 

 3u 2 



