Miscellaneous, 511 



humble cultivator. M. Guerin also proposes to act directly by the 

 same process on the egg of the silkworm ; but his experiments on this 

 object were not sufficiently completed to be brought under the notice 

 of the Commission. 



At Sainte-Tulle, the establishment of M. E. Robert, the crop 

 amounted to 381 k. 4h., and did not present any appearance of mus- 

 cardine. Up to this period the establishment had every year been 

 more or less ravaged by the disease. 



At the establishment of M. J. Coutet, which is precisely opposite 

 that of M. E. Robert, one-fourth of the silkworms had been thrown 

 out of the window, and during the few minutes which the Commission 

 spent near the frames, its members collected several of the animals 

 seized by the contagion. The return would be nothing, or very 

 miserable. 



The vast establishment of Madame Robert, situated about 100 paces 

 from that of M. E. Robert, was closed, but the heaps of diseased 

 worms which were found thrown out, sufficiently indicated the state 

 of the crop. Madame Robert, from 22 ounces (.550 gr.) of eggs, has 

 only obtained a return of from 25 to 30 kilogr. of cocoons. The Com- 

 mission was unable to see the other establishments at Sainte-Tulle, 

 but it appears that their state was very similar. 



At Rousset, at the establishment of MM. Eugene Robert and Co., 

 the crops from 1845 to 1850 had diminished, owing to the ravages of 

 the muscardine, from 500 kilogr. of cocoons for 500 gr. of eggs, to 

 106 kilogr. in 1850. The net produce of this year is 456 kilogr. 

 5 hect. — difference 350 kilogr. 5 hect. Other establishments in the 

 neighbourhood in which the process of M. Guerin-Meneville had not 

 been applied presented the same results as those at Sainte-Tulle. 



In presence of these facts the Commission would not hesitate to 

 pronounce the object attained and the plague of epidemic muscardine 

 vanquished, if a wise resei*ve did not render it advisable to multiply 

 experiments before proclaiming this great service rendered to agricul- 

 ture. It expresses a wish therefore that a new inquiry should take 

 place in 1852, and that the commission to be appointed should visit 

 the establishments at Sainte-Tulle and Rousset not only at the period 

 of gathering, but during the whole course of the cultivation. 



In conclusion, the Commission recommends the laborious and use- 

 ful researches of ^I. Guerin-Me'neville to the notice of the Govern- 

 ment. — Revue Zoologique. 



On the Petrifaction of Organized Bodies {especially Shells) in the 

 existing Seas. By M. Marcel de Serres. 



I believe it was first proved by me that, like the seeds of Chara 

 in the lakes of Scotland, shells are even now becoming petrified in 

 the bosom of the Mediterranean. It is only necessary for this pur- 

 pose that the water, whether fresh or salt, should contain a suffi- 

 cient quantity of calcareous salts, to take the place of those which 

 composed, during life, the shells of Mollusca, the solid tubes of An- 

 nelida, the stony habitations of polypes, or lastly woods and seeds. 



Repose does not appear to be necessary for this substitution, for it 

 takes place in the midst of the violent agitations of the sea ; but there 



