292 Proceedings of Royal Society of Edinburgh. [sess. 
I. 
II. 
Oxygen, 
16*21 
16-79 
Carbonic anhydride, 
32-92 
34-24 
Nitrogen, ....... 
1-09 
1-98 
It may be stated that the oxygen and carbonic anhydride in the 
blood of the Invertebrata do not behave according to the law of 
Dalton (the law of partial pressures) in regard to the absorption of 
a mixture of gases by a simple fluid. A portion of each gas 
combines chemically with some constituent or constituents of the 
blood. It was Magnus ( Poggendorjf s Annalen , vol. xl. p. 583) 
who first demonstrated that the carbonic anhydride and oxygen of 
the Vertebrate blood did not obey the law of Dalton; and the same 
is true concerning the gases of the blood of the Invertebrata. 
II. The Mineral Matter in the Blood. — The percentages of saline 
matter contained in the blood of various Invertebrates is given in 
the following table : — 
I. 
II. 
III. 
Average. 
j 
r Helix pomatia, . 
1-065 
1-072 
1-069 
1-068 
O 2 05 
| Helix aspersa, . . . 
Limnceus stagnalis, . 
1-079 
1-080 
1-062 
1-077 
•Sill 
1-200 
1-203 
1-210 
1-204 
(S 
1 Limax flavus , . 
( Limax maximus, 
1-122 
1-119 
1-100 
1-127 
1-115 
1*114 
1-112 
1-120 
.2 i . 1 
( Buccinum undatum , . 
1-699 
1-710 
1-698 
1-702 
i Patella vulgata,'- 
1-706 
1-721 
1-719 
1-715 
si 
1 Anodonta cygnea , 
1-002 ' 
■ 0-998 
1-006 
1-002 
pq 
K Mytilus edulis, . 
1-796 
1-799 
1-810 
1-801 
i| j 
| Sepia oflicinalis, 
2-840 
2-862 
2-851 
2-851 
o ,5 
| Octopus vulgaris , 
3-004 
3*032 
3-020 
3-018 
The author has also submitted to analysis the ashes of the blood 
of several Invertebrate animals. The ashes were obtained by 
incinerating the blood, partially covered, in a platinum dish at a 
very low temperature. By so doing the alkaline metals are not 
volatilised as they are when a high temperature is used. The 
following results represent the averages of three analyses in each 
case : — 
