AND ITS EFFECTS UPON ANIMAL LIFE. 23 



Til experiment No. :V,\, witli :i series of six rabbits confined for foi'ty-two days, 

 tile [)ro[iortion of earhonic acid in tlie last two jars, for the greater part (^f the 

 time, was between 4 and 7 per cent, and tiiat of oxygen between 12 and 1(5 per cent. 

 None of tlie animals died or were seriously ill. Those in the first three and in the 

 fifth jar gained in weight, those in the fourth and sixth lost slightly in weight. 



The results of blood-corpuscle counts made for five of these animals at the close 

 of the experiment, and again thirty-eight days afterward, show an average increase 

 during this period of 158,600 red, and 5,400 white corpuscles pei' cubic millimetre, 

 an amount which has little significance. Microcytes were found in the blood of the 

 animals immediately after the ex[ieriiiieiit,but none were found thirty-eight days later. 



The organs of a number of the animals that died in these experiments were pre- 

 served in alcohol and examined microscopically. The changes noted post mortem 

 were those of profound venous congestion of all the internal organs. The lungs 

 were frequently so charged with venous blood that the portions preserved for 

 microscopic examination failed to float in water. The right side of the heart was 

 usually dilated with a large firm venous clot, the left ventricle was in most instances 

 contracted. The liver, on incision, bled freely, as did also the kidneys and sj^ileen, 

 the blood being quite dark and venous. All the ca[iillaries were unusually promi- 

 nent, being filled with venous blood; this was particularly noticeable in the small 

 intestine, and in the membranes of the l)rain. 



Microscopic examination of the organs presented a picture coinciding with the 

 gross post-nioi'tem appearances. In the lungs the capillaries were found to be dis- 

 tended with blood, occluding in many cases the lumen of the alveoli aiul air cells, 

 and presenting a typical picture of passive hypera^mia. In the liver, kidneys, and 

 spleen, as well as in the intestines, the capillaries were likewise overloaded with 

 blood. Pathological changes wei'e but rarely noted, and some of these, such as 

 slight proliferation of connective-tissue elements between the tubules of the kidney, 

 and, in rarer instances, in the inter-lobular spaces of the liver, are such as are occa- 

 sionally found in animals which have not been subjected to such conditions, and 

 may, therefore, have existed in the animals at the beginning of the experiment. All 

 the changes which were constantly present may properly be attributed to the action 

 of the carbonic acid and the low percentage of oxygen in the atmosphei'e, interfering 

 with the circulation and aeration of the blood. The lesions reported by Brown- 

 Sequard and d'Arsonval as characteristic in such cases were not seen. No focal 

 necroses or peculiar uniform degenerative changes wei'e found. The results of these 

 experiments, therefore, do not agree with those reported by Brown-Sequard and 

 d'Arsonval — and furnish no evidence of the existence of an oi-ganic poison in the 

 air expired by animals. 



