517 



and sometimes at their base : in the first case, parts similar to those 

 removed were invariably reproduced in different states of develop- 

 ment, and in the latter, entire new limbs were formed ; in some in- 

 stances, at the second change of the larva, when it passed into the 

 pupa state ; but in two or three instances no reproduction took 

 place. At first view, this difference in the results might appear to 

 favour the opinion that this reproduction of limbs depends on the 

 existence ot parts especially adapted to perform this function, and 

 which, in those experiments that had failed to exhibit the pheno- 

 menon, had been themselves removed. But the author found that 

 in every instance of the mutilations thus practised, the perfect in- 

 sect possessed a coxa, or basilar part of the limb ; and this was the 

 case even in those in which a new organ was not reproduced. From 

 this fact, taken in conjunction with the formation of new entire limbs 

 in the lulidae after the removal of every portion of the previous 

 ones, the author infers that the power of reproduction resides in the 

 whole of the organized tissues. 



The author found that each newly produced limb is, in every 

 case, composed of all its essential parts, namely coxa, femur, tibia, 

 tarsus and claw ; but its development is scarcely ever entirely nor- 

 mal, being either deficient in some of the tarsal joints, or irregular 

 in the development of its armature. 



The following are the general conclusions which the author de- 

 duces from his investigations. Slight wounds in the larvae of insects 

 always heal, except when the viscera have protruded, or excessive 

 hemorrhage has occurred : severe wounds, such as those attending 

 the excision of a limb, also frequently heal. It is when the wound 

 is in the line of action of the principal muscles of the body that pro- 

 trusion of the viscera takes place. For the healing of wounds, the 

 first requisite is the arrest of the hemorrhage ; and this is eff'ected, 

 as in the higher animals, by the coagulation of the blood, and the 

 formation of a clot; and then a complete union of the separated 

 parts takes place beneath the eschar formed by the clot. After this 

 union, the reparation of the injury is commenced by a development, 

 from the injured surface, of parts corresponding to those that had 

 been removed. For the production of a new limb, one change of 

 skin, at least, is necessary. The healing of the wound after the 

 removal of a part, and the subsequent reproduction, although they 

 do not prevent, yet certainly retard the natural changes. Lastly, 

 the author has established the fact, that reproduction of lost parts 

 takes place in metabolic as well as in the ametabolic articulata. 



The paper is accompanied with drawings of reproduced parts. 



5. " On the Changes of Temperature produced by the Rarefaction 

 and Condensation of Air." By James Prescott Joule, Esq. Com- 

 municated by P. M. Roget, M.D., Sec. R.S. 



In order to estimate with greater accuracy than has hitherto been 

 done the quantities of heat evolved or absorbed during the conden- 

 sation or rarefaction of atmospheric air, the author contrived an 

 apparatus where both the condensing pump and the receiver were 



