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SUPPLEMENT, &c. 



Mr Needham, who was contemporary with 

 Butfon, endeavoured to prove that all seminal 

 animalcules, so called, in place of being really 

 animated beings, are only prodigiously small 

 machines. He will be best understood in his 

 own words, when describing the milt of the 

 Calmar, a species of cuttle-fish, whose seminal 

 animals resemble spiral springs inclosed in 

 a transparent case. " When the small ma- 

 chines," he says," have come to maturity, se- 

 veral of them act as soon as they are exposed 

 to the air. Most of them, however, may be 

 commodiously viewed by the microscope be- 

 fore their action commences ; and even before 

 they act, it is necessary to moisten with a drop 

 of water the superior extremity of the exter- 

 nal case, which then begins to expand, while 

 the two slender ligaments that issue out of the 

 case are twisted and contorted in different 

 ways. At the same time, the screw rises 

 slowly, and the spirals at its superior end ap- 

 proach each other, and act against the top of 

 the case, those which are lower seeming to be 

 continually followed by others that issue from 

 the piston ; I say, that they seem to follow ; be- 

 cause I believe it to be only a deception produced 

 by the motion of the screw." We need not 

 pursue his remarks further, as they would be 

 unintelligible without a diagram. We may, 

 however, add Buffon's remark upon his theory. 



Mr Needham concludes that it is natural to 

 imagine that the total action of this machine 

 is occasioned by the spring of the screw. But 

 unfortunately, he proves by several experi- 

 ments, that the screw is acted upon by a power 

 residing in the spongy part : as soon as the screw 

 is separated from the rest of the machine, it 

 ceases to act, and loses all motion." What 

 then is the sum of Mr Needham's hypothesis ? 

 Simply this : that spermatic animals, like all 

 other living creatures, considered apart from 

 the vital principle, are machines ; but that 

 these machines have within them a motive and 

 active force; or in other words, they are endued 

 with vitality, by which they move and act in- 

 dependently of any external agent. The ques- 

 tion of vitality, is not perilled by the statement 

 that " even before they act, it is necessary to 

 moisten the upper extremity." Sustenance is 

 necessary to all animals ; the organs cannot 

 act without a material on which to act, and 

 the inactivity of the organs is death or a sus- 

 pension of vitality. The fact of apparent death, 

 and repeated revivescence, at the pleasure of 

 the experimentalist, is strikingly witnessed in 

 the case of some Infusoria, that die when 

 the moisture in which they exist evaporates, 

 and revive again so soon as new fluid is ap- 

 plied to them. This phenomenon, it will also 



be remembered, is observable in a class of ani- 

 malcules exhibiting a peristaltic action , and con- 

 sequently identified with animal existences. 



Buffon, as an additional argument against 

 the actual vitality of seminal and other ani- 

 malcules, instances the fact of minute active 

 particles being found in various substances 

 and under circumstances that totally preclude 

 a living principle. These are nothing more 

 than what in the present day are designated 

 the active molecules of matter, those simple 

 inorganized particles of every description of 

 bodies which exhibit a singular and uniform 

 activity, arising, as we have previously sup- 

 posed, from their mutual action upon each 

 other. And though when the seminal animals 

 are crowded together, their motions appear to 

 be almost the same with those of the molecules, 

 we no sooner thin the multitudes of the former, 

 and spread them over a larger space, than we 

 distinctly perceive that their motions are inde- 

 pendent of external causes, and are directed 

 by a principle of volition resident in the indi- 

 viduals. 



Having stated and replied to the principal 

 objections that have been urged against the 

 vitality of seminal animals, we shall briefly 

 advert to the wild speculations which arose out 

 of their discovery. Leeuwenhoeck and many 

 others strenuously contended that these ani- 

 malcules were really miniatures of human 

 kind ; " but what is still more amazing, Da- 

 lenpatius saw one of these animals break 

 through its coat or covering : it was then no 

 more an animalcule, but a real human body, 

 in which he easily distinguished the two arms 

 and legs, the breast and the head." ! The 

 doctrine of evolution, as it is termed, seemed to 

 be established by the discovery of the sperma- 

 tic animalcules : " according to it, all animals 

 have existed from the first creation as perfect, 

 preformed germs, within their ancestors, the 

 succeeding generations being lodged in the 

 preceding ones like nests of boxes, and pro- 

 gressively developed." There is a point where 

 human reasoning must pause : in the present 

 case, we must be content to know that the proli- 

 fic animal fluid contains myriads of living crea- 

 tures whose purpose in the generative economy 

 still remains unknown. What new discoveries 

 may be made concerning them with the vastly 

 improved instruments now in use, it is impos- 

 sible to say ; we may however, venture an 

 opinion that philosophic inquiry cannot be 

 better employed than in eliciting by all the 

 legitimate means which art and science 

 progressively supply, more and more of the 

 mysteries and wonders connected with the 

 continual succession of animated beings. 



