ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
553 
(SnC] 2 ). If the tissue contains the slightest trace of phosphorus, it 
becomes stained a coerulean blue colour in consequence of the formation 
of ammonium phospho-molybdate, and of the reduction of this body 
with the formation of sesquioxide of molybdenum. Some botanists have 
raised objections to this test on the ground that the staining is due to 
xanthoproteic acid, or to an excess of molybdate, while others have ex- 
pressed doubts as to the value of the method in testing for phosphorus 
in lecithins, nucleins, glvcero-phosphates, &c. To these objections the 
author replies, and shows that, — (1) Xanthoproteic acid has no influence 
on the phosphorus reaction. (2) On account of the solubility of ammo- 
nium molybdate in water, and the insolubility of phospho-molybdate, the 
preparations can be perfectly freed from the former by washing. (3) The 
green or brown staining which often occurs with chloride of tin solu- 
tion is to be ascribed to excess of the reagent. (4) Ammonium molyb- 
date converts the phosphorus in all compounds into ammonium phospho- 
molybdate. 
The above described method is therefore perfectly trustworthy for 
the microscopical demonstration of phosphorus in all organic tissues. 
Ethereal Oils in Microscopical Technique.* — Mr. H. Jordan has 
found that some examples of oleum cajuputi viride and oleum cajuputi 
album dissolve celloidin. He has remarked that the solvent action is 
unusually frequent after Calleja’s method for staining connective tissue. 
Oleum linaloes stands the test well. 
Fig. 146. 
Convenient Washing Apparatus-! — Mr. E. M. Wilcox describes a 
washing apparatus which is especially adapted for laboratory use (fig. 
146). It consists of a jar or a series of jars, each of which is closed with 
* Zeitschr. f. wiss. Mikr., xvi. (1899) pp. 46-7 J 
t Journ. Applied Microscopy, ii. (1899) p. 396 (1 fig.). 
