Page:Popular Science Monthly Volume 58.djvu/591

Rh and its form after contraction in the 'tayle which retains those windings and turnings.'

He discovered also the Rotifers, those favorites of the amateur microscopists, made so familiar to the general public in works like Gross's 'Evenings at the Microscope.' He showed their remarkable powers of resuscitation after complete drying. He observed that when water containing these animalcules evaporated they were reduced to fine dust, but became alive again after great lapses of time by the introduction of water.

He made many observations on the microscopic structure of plants. Fig. 9 gives a fair sample of the extent to which he observed the cellular construction of vegetables and anticipated the cell-theory.

While Malpighi's work in that field was more extensive, these sketches from Leeuwenhoek represent very well the character of the work of the period on minute structure of plants.

It remains to say that on the two biological questions of the day he took a decided stand. He was a believer in preformation or predelineation of the embryo in an extreme degree, seeing in fancy the complete outline of both maternal and paternal individuals in the spermatozoa, and going so far as to make sketches of the same. But upon the question of the spontaneous origin of life he took the side that has been so triumphantly demonstrated in this century against the occurrence of spontaneous generation.

We see in these three gifted contemporaries different personal characteristics. Leeuwenhoek, the composed and strong, attaining an age