CLASSIFICATION. 45 



some of these also are included in the pathologic division, though most of them 

 are classed as normal with localized anomalies. Moreover, it has been found that 



"A certain number of specimens can not be classified satisfactorily in any of the 

 groups, either normal or pathologic. For example, we have in our collection 4 specimens 

 of cyclopia. One is in an embryo which is perfectly normal, except that it contains a 

 single eye; the second is a stunted embryo which is more or less macerated; the third is 

 a fetus compressus, and the fourth is a double monster. These have been entered in our 

 catalogue as follows: Normal with cyclopia; stunted with cyclopia; fetus compressus 

 with cyclopia; double monster with cyclopia. These varieties naturally include all 

 specimens usually designated as monsters. The double monster mentioned above, 

 curiously enough, becomes recorded as a normal twin embryo with cyclopia, but it is 

 difficult to avoid this contradiction with the method of classification we have adopted." 



The pathologic division, which does not comprise the greater number of 

 specimens, is subdivided into seven classes, largely on the basis of the degree of 

 destruction of the ovum or embryo. This holds unless we are to assume that the 

 chorionic and amniotic vesicles can develop regardless of the presence of a cyemic 

 primordium. Particularly in the first three groups, the degree of destruction of 

 the cyema is the determining factor, for in all of the specimens in these groups it 

 is missing. (1) The first group among the pathologic is composed of small remnants 

 of specimens which usually are found to consist of villi only; most of these are 

 derived from tubal pregnancies. (2) The second group is composed of small 

 specimens which are represented by chorionic vesicles wholly devoid of contents 

 save blood and the disintegration products of the embryo and amnion, blood, 

 coagulum, or magma. (3) In the third group are placed specimens in which, in 

 addition to the chorion, the amnion, in part or in its entirety, is present. These 

 specimens usually are somewhat larger. 



Although the absence of the cyema is the determining factor for the inclusion 

 of a specimen in the first three groups in the pathologic division, its presence, no 

 matter in how modified a form, is the criterion which places the specimen in one 

 of the last four groups of this division. In general, it may be stated that the speci- 

 mens in the last four groups are classified according to the degree of the change 

 which they have undergone. "If the embryo is affected so as to appear as an 

 amorphous nodule, it is placed in group 4; but if a cephalic or caudal extremity 

 still can be recognized, it is placed in group 5." The word affected, as used here 

 by .Mall, does not, however, carry with it the idea of dismemberment by force, 

 for a macerated fragment of a normal embryo manifestly should not be classed 

 here. However greatly the form of an embryo may have been modified, this 

 modification must not have resulted from the mechanical removal of a portion of 

 its substance. It is true that it is often impossible to determine whether a given 

 modification in form has thus arisen. Sometimes, indeed, it is impossible to dis- 

 tinguish, by external examination alone, the stump of a cord or the yolk-sac from 

 a nodular embryo, for in the main the classification of a specimen is determined by 

 inspection alone with or without the aid of low magnification. Some of the speci- 



