90 STUDY OF A HUMAN SPINA BIFIDA MONSTER WITH 



Owing to this mass of complicated material and to the widely different nomen- 

 clatures used by the large number of investigators who have worked on the problem, 

 the literature is enormous and rather confused. The classification is still very 

 superficial. In teratology, as in general pathology, the trend has been to supplant 

 classifications based on regional distribution by those having an etiological basis. 

 There exists still in the literature on spina bifida a great deal of the former 

 method. This is due to the fact that until quite recently study has been of external 

 form alone, from which method only a crude regional classification can result. 

 By the application of the more penetrating methods of modern anatomy, 

 embryology, and experimental biology, progress has been made toward etiological 

 classification. 



In 1881 Koch assembled a number of different forms of spina bifida. He 

 pointed out the distinction between the flat-spine form, in which the spinal cord is 

 uncovered (spina bifida aperta), and the cystic or subcutaneous form, in which the 

 soft parts have joined but the bony arches remain ununited. He attributed a 

 later formative period to the subcutaneous than to the open form. In 1S8G von 

 Recklinhausen presented over 30 specimens of spina bifida and focussed attention 

 especially upon the pathological anatomy of the central nervous system and its 

 membranes in the fetal and older forms. By thoroughly analyzing the conditions 

 met with and applying the conception of arrested development, he was able to offer 

 reasonable interpretations for much of the developmental mechanism which up to 

 that time had not been understood. Contemporaneously with these two writers, 

 and since their time, many aspects of the subject have been studied. The surgical 

 treatment of spina bifida has been taken up by many, notably Bayer, Hildebrand. 

 and Muscatello. Other authors have described special types of the abnormality 

 Among these may be mentioned Lewis's paper on iniencephaly. He collected 

 23 cases similar to the one herein described, which show some of the variations 

 presented by this special form. In the literature are to be found fairly numerous 

 descriptions of young specimens with spina bifida. In "A study of the causes 

 underlying the origin of human monsters" (1908), Mall describes 12 from his col- 

 lection and cites several others from the literature. An interesting 8 mm. ferret 

 embryo with localized cervical hydromyelia was described by Good in 1912. 



Experimental studies on the lower animals have formed a very important 

 source of information with regard to the open variety of spina bifida. In Mall's 

 paper a review of the literature on the subject up to 1908 is given. The work of 

 Hertwig and Morgan has attracted especial attention, the former showing that 

 external agents causing delay in the closure of the blastopore can bring about 

 embryological spina bifida. The work of the latter author has been interpreted as 

 pointing toward NaCl as the definite etiological agent, as he was able to produce 

 a delayed closure of the blastopore in frogs' eggs through the use of a 0.6 per cent 

 solution of NaCl. Embryological spina bifida has also been produced occasionally 

 in chicks by overheating and various other methods. Working with frogs' eggs, 

 by ultra-violet-ray exposures Baldwin (1915) obtained a condition of doubled 

 and closed neural canal and sometimes doubled cord. His specimens were usually 



