Royal Society of Edinburgh. 135 
plied as to abound in every part of the island. Its comparative 
rareness in Britain he attributes to two causes: one, the circumstance 
of the very young toad being, as he believes, destitute of the acrid 
fluid; another, the intolerance of the toad of all ages of severe 
cold, and in consequence, its liability to perish if the winter tem- 
perature be unusually low. 
In a foot-note, he expresses the opinion, founded on one observa- 
tion, that the female toad during the breeding season is without the 
protecting acrid fluid, the male at that time having it in more than 
ordinary abundance, and, from position, whilst the ova are in tran- 
situ, probably defending his mate. 
3. On Gyrolite occurring with Calcite in Apophyllite in the 
Trap of the Bay of Fundy. By Henry How, Professor of 
Chemistry and Natural History, King’s College, Windsor. 
Nova Scotia. 
(This paper appears in the present number of this Journal.) 
4. On Natro-boro-calcite, and another Borate occurring in the 
Gypsum of Nova Scotia. By Henry How, Professor of 
Chemistry and Natural History, King’s College, Windsor, 
N.S. 
(This paper appears in the present number of this Journal.) 
5. On some Derivatives from the Olefines. By Frederick 
Guthrie, Professor of Chemistry and Physics in the Royal 
College, Mauritius. 
This paper is supplementary to, and forms the sequel of, a series 
of papers which have been published in the “‘ Quarterly Journal of 
the Chemical Society of London.” 
In continuing the examination of the behaviour of the olefines 
towards compound halogens, certain compounds previously described 
have been submitted to a test of homogeneity, of which the following 
is the principle :— 
*‘ If a body be partly dissolved in a solvent, and if the dissolved 
part and the undissolved part, or the dissolved part and the whole, or 
the undissolved part and the whole, have the same composition, then 
the body is a simple one.” 
Examined in this manner with regard to the solvent alcohol, the 
bisulphochlorides of ethylen and amylen were shown to be true 
chemical compounds. 
The bisulphochloride of ethylen was submitted to the action of 
