and Laboratory Methods. 1709 



or Weigert. Large radulae require 2 to 3 hours of the undiluted stain, the 

 smaller forms 3 to 6 hours of stain diluted with an equal volume of distilled 

 water. Overstains should be reduced with dilute warm caustic potash. 



C. A. K. 



spec, F. Graf v. Die Implantation des Meer- Evidence is accumulating that a variety 

 schweincheneies in der Uteruswand. Zeit- , ,.^. ., , 



schr. f. Morph. u. Anthrop. 3 : 130-182, oi conditions prevail among mammals 



Taf. v-xi, 1901. in the relation of embryo to uterus. 



With ova which attain considerable growth before they become attached to 

 the uterine wall there is no destruction of the uterine epithelium in fixation. 

 In the case of small ova early attached, as in the rat, mouse, guinea pig, and 

 probably also in man, the uterine epithelium is broken down and the egg sinks 

 into the subjacent mucosa. A very important paper by Professor Graf v. Spee, the 

 veteran embryologist, deals with these changes in the guinea pig. The process 

 of implantation of the embryo is accomplished in this animal during the seventh 

 and eighth days after copulation, usually in the second half of the seventh day, 

 and occupies four to eight hours. A full series of ova illustrating all the stages 

 in the process is obtained with difficulty, owing to the uncertainty as to the exact 

 time of fertilization of the egg. A range of about six hours, a period almost equal 

 to that required for implantation, must be allotted for this uncertainty. The 

 embryos are usually found, at this stage, in the antimesometrial angle, or near it, 

 and the whole uterus must be sectioned and examined with a magnification of 

 at least 50 diameters before the one or two ova which it contains can be located. 

 The author compares the action of the egg upon the uterine walls to that of 

 a parasite upon the tissues of its host. The uterine tissues are relatively passive 

 while the egg is apparently the active agent in the process. The egg has reached 

 a late stage of cleavage and exhibits a small cavity at the time of implantation. 

 The cells of the pole, which later is attached to the epithelium of the uterus, 

 send out processes through the zona pellucida, which soon is cast off from the 

 egg. These ultimately fasten to the epithelium, which is unbroken, and whose 

 subjacent connective tissue and blood vessels are in all respects normal. The 

 naked egg exercises a profound influence upon the maternal tissues. The 

 epithelium gives way, apparently without destruction of cells, though nuclei are 

 crowded and cells are displaced. No cell division is found in the epithelium, 

 and its normal condition is renewed after the egg sinks within it. The adjacent 

 connective tissues exhibit phenomena approaching necrosis ; cell division ceases 

 for some distance about the invading egg, the cells degenerate and a fluid gathers 

 about the egg. A well defined sphere of influence can thus be detected in the 

 tissues about the egg. At a later stage an active reaction of the uterus takes 

 place in the development of a granulation zone in the margin of the unaffected 

 tissues, which later has to do with the development of the placenta. 



C. A. K. 



Webster, J. C. Human Placentation. An Ac- Great differences of opinion have long 



count of tfie Changes in the Uterine Mucosa . , , ,, 1 • ^ t j • ^1 • 



and in the attached Foetal Structures during existed on the subject dlSCUSSed m this 



Pregnancy. 120 pp., 14 figs, and 30 plates, work, which is a presentation, in book 



W. T. Keener & Co., Chicago, 1901. $3.75- f^^in, of Dr. Webster's Studies of the 



relations of fcetal and maternal tissues in the placenta. The work is compre- 

 hensive in scope, the discussion is succinct and abundantly illustrated. From 

 comparative and phyllogenetic standpoints as well as from his own investigations 

 and those of others, the author concludes that all of the epithelium found on the 

 villi of the human chorion is of fcetal origin, thus disposing of the older views of 

 Turner, Balfour, and Ercolani which have found acceptance in most modern text- 

 books of the subject. A full bibliography accompanies the text. c. a. k. 



