ACADEMT OF NATURAL SCIENCES. 35 



this chemist, however, not having apparently made so complete a separation of 

 the nickel as Prof. Brush has done. Still it is possible, of course, that differ- 

 ent portions of the mass may differ slightly in composition. 



Dr. Blake read the following paper : 



Infusoria from the Moving Sands in the Neighborhood of 



San Francisco. 



BY JAMES BLAKE, M.D., F.R.C.S. 



The infusoria to which I would call the attention of the Society, were col- 

 lected from the sands in the neighborhood of Point Lobos. These sands form 

 a moving surface, which in dry weather is drifted by the prevailing winds from 

 the shore of the ocean landwards, and are entirely devoid of any signs of vege- 

 tation for some distance from the shore. On walking over these sands when a 

 strong north-west wind was blowing, a wind that does not bring up any fresh 

 sand from the ocean beach at that part of the sand field, I noticed a number of 

 small sized bodies projecting above the surface of the sand as it was being 

 carried onwards by the wind. A closer examination showed that these bodies 

 were formed of particles of sand, agglutinated together by some substance which 

 rendered them almost black, and where dried possessing considerable tenacity. 

 Some of these bodies projected as much as an inch and a half above the surface 

 of the sand, with which however they all remained connected, forming generally 

 small ridges. On examining a portion of this agglutinated sand under the 

 microscope, the water with which I had moistened it was found to be full of 

 infusoria, which commenced moving about as soon as the sand was moistened, 

 although it had been quite dry for some days before being examined. These 

 infusoria probably belong to the genus Monas, but they are so extremely minute 

 that it was impossible to resolve them ; they were, in fact, the smallest living 

 infusoria I had ever examined. With a quarter-inch object glass of Powell and 

 Lelands, they appeared as small globular moving bodies, although occasionally a 

 movement would present one of them with apparently a narrow edge. Nothing 

 much more definite could be made out with the microscope of my friend, Dr. 

 Trask, when using an eighth object glass of Smith and Beck, as they could not 

 be resolved into any form sufficiently definite to classify them. They appeared 

 mostly as globular bodies moving about slowly, and presenting sometimes a 

 longer axis, one end being larger than the other, and offering the appearance as 

 if there was a semi-transparent mass attached to the larger end. The size was 

 estimated at from a fifteenth to the twenty-thousandth of an inch. After a 

 careful examination I was unable to detect any vegetable or organic nucleus 

 which might have served as a nidus for these masses of infusoria. They would 

 seem to become developed in the pure sand, or at least in the sand as it was 

 blown up from the beach, after the salt had been washed out of it by the rain. 

 [I would remark that it had been raining some days before I collected them.] 

 Subsequent researches have shown that these infusoria are very generally 

 diffused through the sands that form our drifting sand-hills around the city ; and 

 on examining some sand taken at a depth of fourteen feet from the surface, 



