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of a drop, lie concludes that the otto was mixed with at least one-third of foreign 
oil. If the otto is adulterated with spermaceti, this substance separates and 
floats on the surface of the solution, or remains suspended in the liquid as a 
scaly crystalline mass. The above test is founded on the circumstance that pure 
otto of roses forms, with strong sulphuric acid, a resinous substance, which is 
completely soluble in absolute alcohol ; while the substance formed with 
other oils is only partially soluble. Guibourt has observed that the odour of 
pure otto is not affected by mixture with strong sulphuric acid, but if other 
oils are present a disagreeable odour is developed — Zeitscht. fur Analyt. 
Chem., No. 4, p. 479. 
The Chemistry of the Development of Silkworms. — An interesting note on 
this subject has been presented to the French Academy by Pelouze. His 
experiments related chiefly to respiration, and have enabled him to draw the 
following conclusions : — 1. The development of the larvae is accomplished by 
the transport and assimilation of part of the nitrogenized matter of the 
mulberry leaves. As the chemical composition and* anatomical structure 
are probably the same throughout this stage of the rearing, in the worm 
just born and in the worm arrived at maturity, the phenomena of nutri- 
tion are equally the same during the various phases of the growth of the 
larvae. 2. The results of the analyses prove a considerable loss of carbon, 
which is found as carbonic acid in the air expired by the insect. The amount of 
carbonic acid shows that in order to fix 100 parts of carbon from the leaves 
the worm consumes from 40 to 50 other parts, which are transformed by 
respiration into carbonic acid. Regnault and Reiset have already remarked 
that the respiration of the silkworm is more active than that of most of the 
animals upon which they experimented. 3. There does not appear to be any 
exhalation or fixation of nitrogen during the development of the silkworm. 
4. The analyses prove a loss of hydrogen that seems to correspond to a loss 
of oxygen, which points to the conclusion that some of the alimentary sub- 
stance disappears in the form of water. — Vide Comptes Bendus, Nov. 20. 
A new body intermediate between Nitric Acid and Ammonia. — In the course 
of a discussion on a paper read at the Birmingham meeting of the British Asso- 
ciation, Section B, by Dr. Calvert, “ On the Action of Acids on some Metals 
.and Alloys,” Dr. Hofmann asked Professor Calvert whether, in his experi- 
ments on the action of acids, and more especially of nitric acid, upon the 
metals, he had met with some of the extraordinary bodies lately observed by 
Dr. Lossen. This young chemist, at one of the late meetings of the Berlin 
Academy, had laid before that body an account of several substances which 
had attracted general attention. It was well known that among the products 
of the action of nitric acid upon certain metals ammonia invariably oc- 
curred. But it appeared that ammonia was only the last product of the 
reaction, and that a whole series of intermediate compounds existed. 
One of these bodies Dr. Lossen had succeeded in isolating. It was a 
compound which, from its composition, might be termed protoxide of 
ammonia, having, in fact, the formula H d NO. This substance, like 
ammonia, combined with acids, producing a series of magnificent salts, 
remarkable for the facility with which they crystallize. The simplest method 
of producing this interesting compound, consisted in submitting nitrate of 
ethyl to the action of metallic zinc in the presence of an acid. It would be 
