Discoi'crcd Rock at Sioux I'ulls, S. D. — Todd. 39 
the other case. The length of time which these conditions 
have continued is somewhat uncertain. Certainly not for the 
whole time since the glacial epoch, but probably for centuries. 
Evidently such a test would be more severe than any to which 
it would be subjected in human reciuirements. 
A dark gabbro near the Lake of the Woods is so magnet- 
ized that a magnetic needle, carried in the hand over its sur- 
face a few yards, will swing through 180°, but no such polar- 
ization of this rock could be detected. 
It resembles closely the Addison stone already mentioned, 
in composition, color and lustre when polished. It is not quite 
so dark, has larger grains and the magnetite is a little more 
conspicuous. That is a very durable rock. Enough exploi- 
tation has been done to show that blocks of any size desired 
may be obtained. 
It may confidently be expected that the stone will become 
a favorite when its excellencies are known. 
EVIDENCES OF RHEUMATOID ARTHRITIS IN 
THE LANSING MAN.* 
By Charles A. Parker, Chicago, 111. 
Although the skeleton is incomplete, yet the articular sur- 
faces of all the larger joints as the shoulder, elbow and wrist, 
hip. knee and ankle are sufficiently well preserved to allow of 
definite statements regarding evidences of former disease in 
them. Evidences of rheumatoid arthritis, or arthritis defor- 
mans, are found in the bodies of the lumbar vertebrae, the head 
of the metatarsal bone of the right great toe, and the articular 
surfaces of the femur and tibia of the right knee-joint. 
'^ ri'.rough the kindness of professor Hawortli. the skeleton of the 
'Lansing Man.' now preserved in the museum of the University of Kan- 
sat--. has heen submitted to me for further examination. After consid- 
erable reparation the hones were siilimittcd ot Dr. Parker, through the 
kindness of Dr. Hektoen, for study, and his report upon them is. here 
published in connection with the literature upon this subject which has 
already appeared in these pages. My early statements concerning the 
skeleton were based upon an examination made while the bones were 
yet unmenaed. and largely concealed in the original matrix, which at 
that time it wa' not thought prudtnt to remove. I quite agree with Dr. 
Parker's determination of the sex. S. W. Willistox. 
