498 PEOFESSOR BERTRAM C. A. WINDLE. 



11. General. 



Mall (vii.) has issued a most elaborate and valuable report 

 upon a number of early via/forrned embryos, the usefulness of which 

 is much increased by the beautiful series of illustrations with which 

 it is adorned. About fifty pathological specimens are described, 

 all of which are abnormal in one or other of two directions, viz., 

 either the embryo is primarily affected or the chorion. His's nodular 

 forms seem to be the earliest. Mall prefers to call these vesicular, and 

 states that they all represent embryos earlier than the second week, 

 since in none of them have the blood-vessels reached the villi of the 

 chorion. The nature of the magma is considered : it is not fibrous, 

 as may be shown by tests, but may become excessively developed 

 and even granular in abnormal ova. Respecting the cells found 

 so widely scattered through the tissues of abnormal embryos. Mall 

 makes the following interesting remarks : " In nearly all instances 

 there are scattered throughout the magma numerous cells with 

 relatively small nuclei and a considerable quantity of protoplasm, 

 showing all the characteristics of the blood-corpuscles of the embryo. 

 These are the migrating cells of His. In all pathological specimens 

 it is found that the migrating cells penetrate all of the tissues 

 of the embryo ; in fact, all of the tissues and spaces within the 

 chorion. My specimens show all of the intermediate stages between 

 blood-vessels filled with blood, with few migrating cells in the 

 tissues, to empty blood-vessels with the tissues stuff"ed with migrating 

 cells. These stages, together with the common morphological appear- 

 ances of the blood-corpuscles and the migrating cells, force the 

 conclusion that the latter are blood-corpuscles within the tissues. 

 It appears as if the blood-corpuscles of the embryo have great 

 power to migrate within the blood-spaces before the heart is 

 formed. In pathological embryos, when the circulation is retarded 

 or arrested, the corpuscles leave the blood-vessels to form a condition 

 which may be termed inflammation of the embryo. As the blood- 

 cells leave the blood-vessels to wander through the tissues, the blood- 

 vessels continue to grow in diameter as well as in extent, for I 

 have numerous specimens in which the aorta is distended and empty, 

 while in other instances capillary vessels, without blood within them, 

 have grown into the villi of the chorion," 



A number of the specimens described are those in which the 

 chorion continued to grow although the embryo was arrested in 

 development; thus a fonr-weeks chorion may co-exist with a two- 

 weeks embryo in it. A number of specimens of this nature are 

 described. Degeneration of the embryo may take place to such 

 an extent as only to leave the umbilical cord, a condition which 

 the writer first thought was one of cylindrical degeneration of the 

 embryo. Sections, however, cleared this matter up and showed 

 the real nature of the condition. At an early stage, after the 

 formation of the amnion, through some unknown causes, the embryos 



