3874 MICROSCOPY. 
He believes the “vegetable spores” of Salisbury and the “ele- 
mentary corpuscles” of Zimmermann are fragments of the larger 
colorless blood corpuscles. For embedding tissues preparatory to 
cutting sections of them, he pins them into the’ centre of little 
boxes extemporized out of white paper, and pours the melted em- 
bedding material around them ; seeming to prefer for this purpose 
the medium suggested by Dr. J. G. Hunt, which consists of 
common transparent soap cut into small pieces and melted ina 
water-bath with the aid of alcohol, this. being a cleanly and trans- 
parent material which can be kept in a bottle and easily melted 
(by placing the bottle in warm water) and poured out when nec- 
essary. The only serious mistake in the book is the measurement 
of the image, in estimating magnifying power, at the distance of 
the stage instead of at ten inches; an erroneous procedure repeat 
edly pointed out by us in other cases, and in this case beautifully 
illustrated by the direction on the same page to measure it, whey 
using the camera lucida, at the distance of ten inches, which of 
course would give the same results in exactly those instruments 
whose stage happened to be ten inches from the observer's eye: 
On the whole, beginners in histology should thank Dr. Tyson for 
a neat, handy, and timely work whose usefulness is far in advance 
of its size. 
MORPHOLOGY or THE SAPROLEGNIEI.— This doubtful i 
that seems now finally deposited in the alge, has now considerable 
economic interest from the destructive effects produced upon fis 
eggs in the hatching trays, supposed to be caused by Achlya pr i 
lifera. The following summary is translated from advance shee pi 
of “ Contributions to the morphology and systematic relation 
the Saprolegniei ;” by N. Pringsheim. (Jahrbuch fur wissenscha 
licher Botanik, ix, Bd. 2tr. Heft.) a 
The results of my investigations on the Saprolegniel mM 
condensed as follows: <4 ae 
1. In all the Saprolegniei the male organs. of generation m 
velop from the well known antheridia, that are formed neat 
grow toward the oogonia. ‘ 
2. Those in which antheridia or their equivalents are "a 
are not, as has been supposed, distinct species, with modifi pud 
gans, but parthenogenetic forms, whose sporangia ripen and bus 
without fertilization. 
ay be 
