and Laboratory Methods. 1213 



ever, only as opaque objects. A tabular view is given ' of the stage of develop- 

 ment of the various organs of the body in 132 embryos of successive ages up to 

 ten days. The authors call attention to those features of the development which 

 are subject to individual variation in the chick. The care with which this work 

 has been done makes this book a valuable work of reference in establishing the 

 age of embryos as well as in the selection of embryos for the study of organology. 

 The book is an indispensable aid in every embryological laboratory. A very 

 full bibliography of the subject occupies fifty quarto pages of the book. 



The fixing agents used were sublimate-acetic and chrom-acetic, and the 

 stains borax-carmin (followed in some cases by bleu de Lyon), para-carmin, 

 and haematein. c. a. k. 



Linko, Alex. Ueber den Bau der Augen bei Material was prepared with aceto- 



den Hydromedusen. Mem del' Acad imp. sublimate, Perenyi's fluid, etc., and 



des Sci. St. Petersbourg. CI. Phys. Math. \ ^ ' ' 



10: No. 3, 1-23, pis. 1-2, 1900. Stained with Delafield's haematoxylin 



or alum or borax-carmin. All attempts 

 to use methylen-blue or the Golgi method in any of their modifications were 

 futile. The depigmentation of the eyes was effected neither by Grenacher's 

 method, by chlorin, nor by eau de Javelle. In some species the pigment was par- 

 tially removed by exposure to Perenyi's fluid for 3-4 hours, though this induced 

 some maceration of the tissvies. Eight genera were examined, exhibiting a wide 

 range in structure. In Catahlevia the eye is a simple pigment fleck, composed 

 of pigmented and of visual cells. In Oceania a pigmented area of similar struc- 

 ture is found in a shallow pit. In Staurostotna the eyes are numerous (400) and 

 vary from a simple pigment spot to the beaker-form eye with vitreous body. In 

 Codoniiim the sensory cells are somewhat retracted and their outer ends exhibit 

 thickenings which terminate in sensory "hairs." In Sarsia a vitreous body 

 occurs and the sensory cells terminate in conical end organs. Sarsia is quite 

 sensitive to the stimulus of light. The eyes of Itaropsis are of the inverted 

 type with pigment cells of entodermal origin. c. a. k. 



Bergh, R. S. Beitrage zur Vergleichende His- Various writers have stated that the 



tologie II. Ueber den Bau der Gefiisse bei blood vessels of Annelids are provided 



den Anneliden. Anat. Hefte IS: 1500-623, -,11 r 1 •. i- 1 1 r 



pis 48-i;i iQoo with a layer of longitudmal, and one of 



circular muscle-fibers, with a lining of 

 connective tissue intima, folds of which form the valves. Others have reported 

 that the blood vessels have an endothelial lining. Bergh has found a number of 

 errors in these statements. Lumbriciis was cut open and pinned out with porcu- 

 pine spines in silver nitrate. The silver was reduced by exposure to sunlight or 

 in alcohol slightly acidulated with formic acid. The mixture of formic acid with 

 the silver solution directly produced too excessive blackening and precipitation. 

 Silver preparations were stained in haematoxylin. Blood vessels for sectioning 

 were freed of their blood by slight pressure before fixing in aceto-sublimate. 

 Sections were stained in haematoxylin or by van Gieson-Hansen's haematoxylin- 

 acid fuchsin-picric method, which leaves the muscle fibers yellow, and the 

 connective tissue ground substance a bright red. Bergh was not able to find an 

 endothelial lining in any of the blood vessels, neither could he detect any longi- 



