Mabch 12, 1909] 



SCIENCE 



429 



from the outside into the " shell gland " without 

 resort to such violent methods as to make the 

 conditions entirely abnormal. Further, the for- 

 eign body introduced should approximate to the 

 consistency of the egg, so that the stimulus may 

 be physiological rather than traumatic. 



To realize these conditions the following opera- 

 tion was performed on hens. The oviduct was 

 transected 1 or 2 cm. above the upper end of the 

 "shell gland." The anterior portion of the ovi- 

 duct was then ligated. The intestine was tran- 

 sected just anterior to the cloaca and the eloacal 

 wall repaired by inversion of the stump and a 

 purse string suture. Then the cut end of the 

 intestine was anastomosed to the cut end of the 

 oviduct ( " shell gland " ) . As a result of this 

 operation the feces must necessarily pass through 

 the " shell gland " on the way to the cloaca. In 

 hens on which this operation has been performed 

 a calcareous shell is deposited on the feces during 

 their passage through the shell gland. The results 

 obtained from these experiments are held to war- 

 rant the following conclusions: 



1. The stimulus which sets the shell-secreting 

 glands of the fowl's oviduct into activity is 

 mechanical rather than chemical in nature. 



2. The formation of a shell on the hen's egg is 

 brought about by a strictly local reflex, and is not 

 immediately dependent upon the activity of other 

 portions of the reproductive system (nervous im- 

 pulse of hormone formation ) . 



Experimental Control of Fission in Planaria: 



C. M. Chiu), University of Chicago. 

 The Artificial Production a/nd the Development of 

 One-eyed Monsters: Chaeles R. Stockaed, Cor- 

 nell Medical School. 



The eggs of the fish, Pundulu^ heteroclitus, give 

 rise to a large percentage of cyclopean embryos 

 when subjected during their development to solu- 

 tions of magnesium salts in sea water. These one- 

 eyed embryos hatch and many of them swim in 

 a perfectly normal manner, darting back and 

 forth to avoid objects placed in their field of vision 

 as readily as do two-eyed individuals. 



The cyclopean fish is entirely comparable to the 

 one-eyed human monsters. Both have a median 

 eye more or less double in structure. The nose in 

 the human cyelops is a proboscis-like mass above 

 the eye. The nasal pits in the " magnesium em- 

 bryos " are sometimes united and sometimes sepa- 

 rate, but the mouth hangs ventrally as a pro- 

 boscis-like organ, suggesting in form the nose in 

 mammalian cyclopia. 

 The fish embryos exhibit various degrees of the 



cyclopean defect from eyes unusually close to- 

 gether to approximated eyes, double eyes and 

 finally a single median eye. The different condi- 

 tions are exhibited from the earliest appearance 

 of the optic outpushings and in no case was 

 cyclopia due to a union or fusion of the two eye 

 components after they had originated separately. 



A second type of monster, " monstrum monop- 

 thalmicum asymmetrioum," was also common in 

 the magnesium solutions. These individuals have 

 one perfect eye of the normal pair but the other 

 is either small, poorly represented or entirely 

 absent. This condition is also present from the 

 first appearance of eye structures and is not due 

 to degeneration or arrest of development. 



Both types of monsters often form well-differ- 

 entiated crystalline lenses independently of a 

 stimulus from the optic-cup. 



The experiments conclusively prove that devel- 

 oping eggs may be induced to form cyclopean 

 monsters by external influences which do not 

 mechanically injure certain eye regions. There- 

 fore, cyclopean monsters in nature are probably 

 not due to germinal variations, but are far more 

 likely the result of some unusual external influ- 

 ence during development. 



Gosmohia; a Theory Concerning Certain Types of 

 Monsters: H. H. Wilder, Smith College. 

 The readiness with which the types of double 

 monsters may be arranged in related series has 

 been recognized for some time, and this phase of 

 the subject has been recently revived. To illus- 

 trate this, the main types of the Janus series 

 were presented, beginning with a symmetrical 

 Janus, passing through the different stages of 

 gnathopagus, thoracopagus, etc., and ending with 

 a type of duplicate twins in which the placenta 

 alone is common, the other parts distinct. This 

 leads to the definition of such twins as double 

 monsters in which the common parts are confined 

 to the extra-embryonal structures. These are lost 

 at birth, freeing the components. The diprosopuB 

 group was treated in the same way. Attention 

 was then called to the fact that in symmetrical 

 monsters that are less than unity the doubled or 

 compound parts, eyes, limbs, etc., are indistin- 

 guishable from those that are found in monsters 

 that are on the other side of the normal, i. e., the 

 diplopagi. As a conclusion from this it seems 

 that both classes of monsters are due to the same 

 or a similar cause, and that normal individuals 

 also belong in the same general series. To such 

 individuals, both less and more than unity, in- 

 cluding also normal forms, the term " cosmohia" 



