ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
759 
peptones to assume a granula form. The granules may be soluble or 
insoluble ; they may be stained with acid fuchsiu and picric alcohol ; 
they are not distinguishable from Altmann’s granula. These facts sug- 
gest the question whether Altmann’s granula is not an artificial product 
due to peptone or propeptone in the animal cells. Peptone solution 
injected into empty pith cells, and then fixed with osmic acid or Alt- 
mann’s mixture, gave rise to a strikingly close imitation of vegetable 
cell-structure. 
Preserving Tow-net Material.* — Mr. J. Rattray never adopted pure 
alcohol ab initio for the preservation of tow-net material, but 70 or 80 
per cent, alcohol, with a small addition of pure hydrochloric acid and a 
trace of picric. After washing with strong spirit to remove the acid, 
the specimens were preserved in spirit. Alger’s adaptation of Kleinen- 
berg’s formula was often used, because of its reported high degree of 
penetrability for chitinized structures ; the fixing agent was simply 
added to the sea water, and was succeeded by increasing strengths of 
spirit. Mayer’s picro-hydrochloric method was only employed a few 
times. Corrosive sublimate was extensively used, Lang’s methods being 
simplified and accelerated by adding a little of the solid salt to the sea 
water. In a few cases, following Carnoy, a trace of acetic acid was 
added to the corrosive solution. 
New Compressorium.'f — Prof. H. E. Ziegler has devised a small 
apparatus by means of which a well-regulated, pressure can be applied 
to the object, while at the same time a stream of fresh water or “any 
other liquid can be drawn through it. 
The apparatus (fig. 102) consists of two metal plates, of which* the 
lower serves as object-holder, while the upper carries the cover-glass. 
Fig. 102. 
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In each plate there is an aperture in the centre. On the opening of the 
lower plate a round piece of thick glass is fixed, while below the opening 
of the upper the cover-glass is cemented. The two plates are kept apart 
by a hollow caoutchouc ring, and can be pressed together by three 
pressure-screws. A constant stream of water can be passed through the 
space between the caoutchouc ring and the plates by means of the two 
tubes in the upper plate. The stream of water is regulated by a stop- 
cock. A small U-tube is attached to the exit-tube to prevent any effect 
of suction on the water in the apparatus. 
The brass parts of the apparatus are protected from the injurious 
effect of reagents by lacquer, but it is advisable to have two apparatus, 
one of which should be kept free from reagents. 
* Trans. Linn. Soc. London, Zool., vi. (1894) pp. 4 and 5. 
f Zool. Anzeig., xvii. (1894) pp. 330-2 and 345-7. 
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