Miscellaneous. 435 



MISCELLANEOUS. 



TWIN MUSHROOM. 



Mr. Anderson, gardener to the Earl of Stair at Oxenford Castle, 

 exhibited at the last Meeting of the Edinburgh Botanical Society a 

 singular twin mushroom, represented in PI. XVI. C. It would 

 appear as if two mushrooms had united together by the summit of 

 their pileus in the young state, and that one had afterwards grown so 

 vigorously as to detach the other from the soil, and bear it on the tip 

 of its pileus inverted. The substance of the pileus of the two mush- 

 rooms is intimately united, as seen in fig. 2. In the lower mushroom 

 the lamellae are as usual in the lower surface, while in the upper sur- 

 face the pileus being inverted the lamellae appear above. 



Fig. 1. shows the two mushrooms united, with the lamellae on both sides. 

 Fig. 2. shows a section through the two mushrooms. 



On the Circulation of the Blood in Insects. By M. Leon Dufour. 



I shall not refer to all the proofs which I have accumulated to show 

 that the tracheary apparatus of insects is solely an organ of respira- 

 tion, a vascular system intended exclusively for the circulation of air. 

 This subtle fluid penetrates, by an infinity of ramifications, into all the 

 tissues, to communicate to them the benefits of respiration, to °ive 

 the blood with which they are imbued that vivification, that nutritive 

 faculty, in search of which, in the higher animals, the vessels come to 

 a circumscribed respiratory organ, either lungs or gills. I only wish, 

 at present, to discuss the new facts lately brought before the Academy 

 in support of the theory of peritrachean circulation. 



That silkworms which have been fed on leaves powdered with blue 

 or rose-colour, produce blue or rose-coloured cocoons, is an incontest- 

 able fact. Neither do I deny the coloration of the tracheae observed 

 by MM. AlessandriDi and Bassi. But, whilst admitting these facts, 

 since proved by M. Blanchard, I am far from coinciding with him in 

 the consequences which he has deduced from them. The blue blood 

 we are told, fills the abdominal cavities, the lacunce, penetrates the 

 dorsal vessel, and nevertheless neither the muscles nor the viscera are 

 coloured ; they preserve their usual whiteness ! What ! those power- 

 ful locomotive muscles, into which, even with the naked eves, we see 

 tracheae of such large size penetrate, to perform the important func- 

 tions of reparation and nutrition, receive no tinge from that blue blood, 

 which, even according to the hypothesis of peritrachean respiration, 

 must insinuate itself everywhere ! And those digestive viscera, so rich 

 in tracheae of all di tensions, the detection of which does not require 

 a microscope or even a simple lens — those ventricular parietes, through 

 which, even according to this author, the blue nutritive fluid trans- 

 udes — these viscera remain white ! And those serific glands, which 

 in the exercise of their secreting faculty can admit the blue colour 

 (for this is transmitted to these cocoons) — these glands offer no ap- 

 pearance of blue ! 



Because the tracheae appear blue, is it necessary to conclude that 

 this can only be caused by the imprisonment of blue blood between 

 an external membrane and the true coat of the aeriferous duct of 



