PHYSIOLOGY OF THE INVERTEBRATA. 135 



blood coagulates normally, although after a longer interval 

 of time, id) Carbon disulphide had no effect for a consid- 

 erable time. Eventually the blood was coagulated (green) 

 but nothing coloured was dissolved out." 



The Action of Heat. — " The blood of the pupa of Sphvaoo 

 Ligustri was heated in a glass tube in a water-bath ; no 

 change was seen till the temperature reached 132° F., when 

 part of the blood became slightly dim. By 141° the whole 

 of the blood was distinctly cloudy, but it was not till 180° 

 that the blood became quite coagulated — solid-looking and 

 opaque, the proteids being yellow with xanthophyll. In the 

 interstices of the clot was a clear yellow fluid. The xantho- 

 phyll in the coagulum was easily extracted by ether or 

 alcohol." 



Dr. L. Predericq* has also investigated the nature of the 

 blood in the Insecta. He experimented upon the blood of 

 the larvae of Oryctes nasicornis (belonging to the Coleoptera). 

 The blood was extracted by making a small slit (with fine 

 scissors) across the skin of the back and the walls of the 

 dorsal vessel ; into this slit a slender glass canula was inserted 

 when the blood of the animal immediately rose in the tube. 

 The blood is a colourless liquid having somewhat the aspect 

 of the lymph of the Mammalia, and holding in suspension a 

 large number of colourless globules which slightly interfere 

 with its transparency. The blood of Oryctes quickly coagu- 

 lates. This coagulation is not arrested by the addition of 

 sodium chloride, magnesium sulphate, &c. But a slightly 

 elevated temperature (54° C.) sufficed to prevent coagula- 

 tion. 



When exposed to the air the blood of this insect becomes 

 a dark brown colour ; but the brown colour has not the same 

 intensity throughout the fluid ; it is of a deeper colour in the 

 vicinity of the mass of globules. Light has no action in 

 changing the colour; the change being due to oxidation. 

 After being coagulated with hot water, the blood of Oryctes 

 * Bulletins de I'Acadimie Boyale de Belgijue, y s&rie, tome i. 



