4IS Dr. Kidd on the Anatomy 



upon observing them with a magnifying lens, I perceived that 

 they exactly resembled a crystallized rosette of brown pearl- 

 spar. Upon being removed and submitted to the requisite 

 experiments, they proved to be of considerable hardness, 

 sparry in their structure, and insoluble either in boiling water 

 or alcohol ; but they were dissolved with rapid effervescence 

 in diluted muriatic acid. These calculous concretions were 

 probably the result of diseased action in the vesicular glands, 

 round the orifices of the excretory ducts of which they had 

 been dej)osited. 



The blood. — Upon wounding the animal in almost any part 

 of the body, even in cutting off a portion of the caudal an- 

 tenna, there oozes out a very clear thin fluid of a bright honey- 

 yellow colour, having sensibly alkaline properties, and cor 

 agulating either by heat or by the addition of alcohol. A 

 quantity of this fluid, weighing 1*85 grain, being evaporated 

 under an exhausted receiver, in which was placed dry muriate 

 of lime, left a solid residuum of a bright golden yellow colour, 

 which weighed 0*25 grain : this residuum was brittle, and 

 had the general properties of solid albumen. The foregoing 

 characters render it highly probably' that the yellow fluid dis- 

 tributed through the body of the insect resembles in its na- 

 ture the serum of common blood ; and there can be no doubt, 

 arguing physiologically, that this yellow fluid is the blood or 

 nutrient juice of the animal. I wish I could as satisfactorily 

 show the means employed by nature to distribute this fluid 

 through the system of this and other animals of the same 

 class ; for, though I cannot hope to discover what more ex- 

 perienced and skilful anatomists have sought in vain, namely, 

 a heart, and a system of circulating vessels ; yet I cannot sub- 

 scribe to their opinion, that the blood transudes through the 

 coats of the intestines, where of course it must be primarily 

 formed, and thence passes, as through the pores of a sponge, 

 to every j}art of the body. Both Cuvier and M. Marcel 

 de Serres completed a very elaborate set of experiments for 

 the purpose of ascertaining whether the dorsal vessel of in- 

 sects sends out any lateral branches which might serve the 

 purpose of a circulating system, or whether any other distinct 

 circulating sj'Stem exists ; but they have entirely failed in their 

 endeavours :. and I feel assured that where such men have 

 failed, others will not succeed; and yet their consequent sup- 

 position, that the blood is diffused through the general sub- 

 stance of the body, appears to me very highly improbable. 

 It accords not with the general character of those means by 

 which nature usually produces its effects ; there is too little of 

 art and contrivance, if I may use such terms on such an oc- 

 casion. 



